From 9effbb9a6b1b4375f4ae144e6382212cc419171b Mon Sep 17 00:00:00 2001 From: willcrichton Date: Mon, 29 Jul 2024 22:47:11 +0000 Subject: [PATCH] =?UTF-8?q?Deploying=20to=20gh-pages=20from=20@=20willcric?= =?UTF-8?q?hton/flowistry@4e8a1830684067345c7d59969259419785378fde=20?= =?UTF-8?q?=F0=9F=9A=80?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- type.impl/core/result/enum.Result.js | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/type.impl/core/result/enum.Result.js b/type.impl/core/result/enum.Result.js index 00b2e7b9a..6dac47133 100644 --- a/type.impl/core/result/enum.Result.js +++ b/type.impl/core/result/enum.Result.js @@ -2,7 +2,7 @@ "anyhow":[["
source§

impl<T, E> Result<T, E>

1.0.0 (const: 1.48.0) · source

pub const fn is_ok(&self) -> bool

Returns true if the result is Ok.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_ok(), true);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_ok(), false);
\n
1.70.0 · source

pub fn is_ok_and(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the result is Ok and the value inside of it matches a predicate.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.is_ok_and(|x| x > 1), true);\n\nlet x: Result<u32, &str> = Ok(0);\nassert_eq!(x.is_ok_and(|x| x > 1), false);\n\nlet x: Result<u32, &str> = Err(\"hey\");\nassert_eq!(x.is_ok_and(|x| x > 1), false);
\n
1.0.0 (const: 1.48.0) · source

pub const fn is_err(&self) -> bool

Returns true if the result is Err.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_err(), false);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_err(), true);
\n
1.70.0 · source

pub fn is_err_and(self, f: impl FnOnce(E) -> bool) -> bool

Returns true if the result is Err and the value inside of it matches a predicate.

\n
Examples
\n
use std::io::{Error, ErrorKind};\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), true);\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);\n\nlet x: Result<u32, Error> = Ok(123);\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);
\n
1.0.0 · source

pub fn ok(self) -> Option<T>

Converts from Result<T, E> to Option<T>.

\n

Converts self into an Option<T>, consuming self,\nand discarding the error, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.ok(), Some(2));\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.ok(), None);
\n
1.0.0 · source

pub fn err(self) -> Option<E>

Converts from Result<T, E> to Option<E>.

\n

Converts self into an Option<E>, consuming self,\nand discarding the success value, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.err(), None);\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.err(), Some(\"Nothing here\"));
\n
1.0.0 (const: 1.48.0) · source

pub const fn as_ref(&self) -> Result<&T, &E>

Converts from &Result<T, E> to Result<&T, &E>.

\n

Produces a new Result, containing a reference\ninto the original, leaving the original in place.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.as_ref(), Ok(&2));\n\nlet x: Result<u32, &str> = Err(\"Error\");\nassert_eq!(x.as_ref(), Err(&\"Error\"));
\n
1.0.0 (const: unstable) · source

pub fn as_mut(&mut self) -> Result<&mut T, &mut E>

Converts from &mut Result<T, E> to Result<&mut T, &mut E>.

\n
Examples
\n
fn mutate(r: &mut Result<i32, i32>) {\n    match r.as_mut() {\n        Ok(v) => *v = 42,\n        Err(e) => *e = 0,\n    }\n}\n\nlet mut x: Result<i32, i32> = Ok(2);\nmutate(&mut x);\nassert_eq!(x.unwrap(), 42);\n\nlet mut x: Result<i32, i32> = Err(13);\nmutate(&mut x);\nassert_eq!(x.unwrap_err(), 0);
\n
1.0.0 · source

pub fn map<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> U,

Maps a Result<T, E> to Result<U, E> by applying a function to a\ncontained Ok value, leaving an Err value untouched.

\n

This function can be used to compose the results of two functions.

\n
Examples
\n

Print the numbers on each line of a string multiplied by two.

\n\n
let line = \"1\\n2\\n3\\n4\\n\";\n\nfor num in line.lines() {\n    match num.parse::<i32>().map(|i| i * 2) {\n        Ok(n) => println!(\"{n}\"),\n        Err(..) => {}\n    }\n}
\n
1.41.0 · source

pub fn map_or<U, F>(self, default: U, f: F) -> U
where\n F: FnOnce(T) -> U,

Returns the provided default (if Err), or\napplies a function to the contained value (if Ok).

\n

Arguments passed to map_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use map_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let x: Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or(42, |v| v.len()), 3);\n\nlet x: Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or(42, |v| v.len()), 42);
\n
1.41.0 · source

pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
where\n D: FnOnce(E) -> U,\n F: FnOnce(T) -> U,

Maps a Result<T, E> to U by applying fallback function default to\na contained Err value, or function f to a contained Ok value.

\n

This function can be used to unpack a successful result\nwhile handling an error.

\n
Examples
\n
let k = 21;\n\nlet x : Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 3);\n\nlet x : Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 42);
\n
1.0.0 · source

pub fn map_err<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> F,

Maps a Result<T, E> to Result<T, F> by applying a function to a\ncontained Err value, leaving an Ok value untouched.

\n

This function can be used to pass through a successful result while handling\nan error.

\n
Examples
\n
fn stringify(x: u32) -> String { format!(\"error code: {x}\") }\n\nlet x: Result<u32, u32> = Ok(2);\nassert_eq!(x.map_err(stringify), Ok(2));\n\nlet x: Result<u32, u32> = Err(13);\nassert_eq!(x.map_err(stringify), Err(\"error code: 13\".to_string()));
\n
1.76.0 · source

pub fn inspect<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&T),

Calls the provided closure with a reference to the contained value (if Ok).

\n
Examples
\n
let x: u8 = \"4\"\n    .parse::<u8>()\n    .inspect(|x| println!(\"original: {x}\"))\n    .map(|x| x.pow(3))\n    .expect(\"failed to parse number\");
\n
1.76.0 · source

pub fn inspect_err<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&E),

Calls the provided closure with a reference to the contained error (if Err).

\n
Examples
\n
use std::{fs, io};\n\nfn read() -> io::Result<String> {\n    fs::read_to_string(\"address.txt\")\n        .inspect_err(|e| eprintln!(\"failed to read file: {e}\"))\n}
\n
1.47.0 · source

pub fn as_deref(&self) -> Result<&<T as Deref>::Target, &E>
where\n T: Deref,

Converts from Result<T, E> (or &Result<T, E>) to Result<&<T as Deref>::Target, &E>.

\n

Coerces the Ok variant of the original Result via Deref\nand returns the new Result.

\n
Examples
\n
let x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&str, &u32> = Ok(\"hello\");\nassert_eq!(x.as_deref(), y);\n\nlet x: Result<String, u32> = Err(42);\nlet y: Result<&str, &u32> = Err(&42);\nassert_eq!(x.as_deref(), y);
\n
1.47.0 · source

pub fn as_deref_mut(&mut self) -> Result<&mut <T as Deref>::Target, &mut E>
where\n T: DerefMut,

Converts from Result<T, E> (or &mut Result<T, E>) to Result<&mut <T as DerefMut>::Target, &mut E>.

\n

Coerces the Ok variant of the original Result via DerefMut\nand returns the new Result.

\n
Examples
\n
let mut s = \"HELLO\".to_string();\nlet mut x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&mut str, &mut u32> = Ok(&mut s);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);\n\nlet mut i = 42;\nlet mut x: Result<String, u32> = Err(42);\nlet y: Result<&mut str, &mut u32> = Err(&mut i);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
\n
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(7);\nassert_eq!(x.iter().next(), Some(&7));\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter().next(), None);
\n
1.0.0 · source

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns a mutable iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let mut x: Result<u32, &str> = Ok(7);\nmatch x.iter_mut().next() {\n    Some(v) => *v = 40,\n    None => {},\n}\nassert_eq!(x, Ok(40));\n\nlet mut x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter_mut().next(), None);
\n
1.4.0 · source

pub fn expect(self, msg: &str) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message including the\npassed message, and the content of the Err.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.expect(\"Testing expect\"); // panics with `Testing expect: emergency failure`
\n
Recommended Message Style
\n

We recommend that expect messages are used to describe the reason you\nexpect the Result should be Ok.

\n\n
ⓘ
let path = std::env::var(\"IMPORTANT_PATH\")\n    .expect(\"env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`\");
\n

Hint: If you’re having trouble remembering how to phrase expect\nerror messages remember to focus on the word “should” as in “env\nvariable should be set by blah” or “the given binary should be available\nand executable by the current user”.

\n

For more detail on expect message styles and the reasoning behind our recommendation please\nrefer to the section on “Common Message\nStyles” in the\nstd::error module docs.

\n
1.0.0 · source

pub fn unwrap(self) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message provided by the\nErr’s value.

\n
Examples
\n

Basic usage:

\n\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.unwrap(), 2);
\n\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.unwrap(); // panics with `emergency failure`
\n
1.16.0 · source

pub fn unwrap_or_default(self) -> T
where\n T: Default,

Returns the contained Ok value or a default

\n

Consumes the self argument then, if Ok, returns the contained\nvalue, otherwise if Err, returns the default value for that\ntype.

\n
Examples
\n

Converts a string to an integer, turning poorly-formed strings\ninto 0 (the default value for integers). parse converts\na string to any other type that implements FromStr, returning an\nErr on error.

\n\n
let good_year_from_input = \"1909\";\nlet bad_year_from_input = \"190blarg\";\nlet good_year = good_year_from_input.parse().unwrap_or_default();\nlet bad_year = bad_year_from_input.parse().unwrap_or_default();\n\nassert_eq!(1909, good_year);\nassert_eq!(0, bad_year);
\n
1.17.0 · source

pub fn expect_err(self, msg: &str) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a panic message including the\npassed message, and the content of the Ok.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(10);\nx.expect_err(\"Testing expect_err\"); // panics with `Testing expect_err: 10`
\n
1.0.0 · source

pub fn unwrap_err(self) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a custom panic message provided\nby the Ok’s value.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(2);\nx.unwrap_err(); // panics with `2`
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(x.unwrap_err(), \"emergency failure\");
\n
source

pub fn into_ok(self) -> T
where\n E: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Ok value, but never panics.

\n

Unlike unwrap, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap as a maintainability safeguard that will fail\nto compile if the error type of the Result is later changed\nto an error that can actually occur.

\n
Examples
\n
\nfn only_good_news() -> Result<String, !> {\n    Ok(\"this is fine\".into())\n}\n\nlet s: String = only_good_news().into_ok();\nprintln!(\"{s}\");
\n
source

pub fn into_err(self) -> E
where\n T: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Err value, but never panics.

\n

Unlike unwrap_err, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap_err as a maintainability safeguard that will fail\nto compile if the ok type of the Result is later changed\nto a type that can actually occur.

\n
Examples
\n
\nfn only_bad_news() -> Result<!, String> {\n    Err(\"Oops, it failed\".into())\n}\n\nlet error: String = only_bad_news().into_err();\nprintln!(\"{error}\");
\n
1.0.0 · source

pub fn and<U>(self, res: Result<U, E>) -> Result<U, E>

Returns res if the result is Ok, otherwise returns the Err value of self.

\n

Arguments passed to and are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use and_then, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<&str, &str> = Ok(\"foo\");\nassert_eq!(x.and(y), Err(\"early error\"));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"not a 2\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Ok(\"different result type\");\nassert_eq!(x.and(y), Ok(\"different result type\"));
\n
1.0.0 · source

pub fn and_then<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> Result<U, E>,

Calls op if the result is Ok, otherwise returns the Err value of self.

\n

This function can be used for control flow based on Result values.

\n
Examples
\n
fn sq_then_to_string(x: u32) -> Result<String, &'static str> {\n    x.checked_mul(x).map(|sq| sq.to_string()).ok_or(\"overflowed\")\n}\n\nassert_eq!(Ok(2).and_then(sq_then_to_string), Ok(4.to_string()));\nassert_eq!(Ok(1_000_000).and_then(sq_then_to_string), Err(\"overflowed\"));\nassert_eq!(Err(\"not a number\").and_then(sq_then_to_string), Err(\"not a number\"));
\n

Often used to chain fallible operations that may return Err.

\n\n
use std::{io::ErrorKind, path::Path};\n\n// Note: on Windows \"/\" maps to \"C:\\\"\nlet root_modified_time = Path::new(\"/\").metadata().and_then(|md| md.modified());\nassert!(root_modified_time.is_ok());\n\nlet should_fail = Path::new(\"/bad/path\").metadata().and_then(|md| md.modified());\nassert!(should_fail.is_err());\nassert_eq!(should_fail.unwrap_err().kind(), ErrorKind::NotFound);
\n
1.0.0 · source

pub fn or<F>(self, res: Result<T, F>) -> Result<T, F>

Returns res if the result is Err, otherwise returns the Ok value of self.

\n

Arguments passed to or are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use or_else, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<u32, &str> = Ok(2);\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Ok(100);\nassert_eq!(x.or(y), Ok(2));
\n
1.0.0 · source

pub fn or_else<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> Result<T, F>,

Calls op if the result is Err, otherwise returns the Ok value of self.

\n

This function can be used for control flow based on result values.

\n
Examples
\n
fn sq(x: u32) -> Result<u32, u32> { Ok(x * x) }\nfn err(x: u32) -> Result<u32, u32> { Err(x) }\n\nassert_eq!(Ok(2).or_else(sq).or_else(sq), Ok(2));\nassert_eq!(Ok(2).or_else(err).or_else(sq), Ok(2));\nassert_eq!(Err(3).or_else(sq).or_else(err), Ok(9));\nassert_eq!(Err(3).or_else(err).or_else(err), Err(3));
\n
1.0.0 · source

pub fn unwrap_or(self, default: T) -> T

Returns the contained Ok value or a provided default.

\n

Arguments passed to unwrap_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use unwrap_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let default = 2;\nlet x: Result<u32, &str> = Ok(9);\nassert_eq!(x.unwrap_or(default), 9);\n\nlet x: Result<u32, &str> = Err(\"error\");\nassert_eq!(x.unwrap_or(default), default);
\n
1.0.0 · source

pub fn unwrap_or_else<F>(self, op: F) -> T
where\n F: FnOnce(E) -> T,

Returns the contained Ok value or computes it from a closure.

\n
Examples
\n
fn count(x: &str) -> usize { x.len() }\n\nassert_eq!(Ok(2).unwrap_or_else(count), 2);\nassert_eq!(Err(\"foo\").unwrap_or_else(count), 3);
\n
1.58.0 · source

pub unsafe fn unwrap_unchecked(self) -> T

Returns the contained Ok value, consuming the self value,\nwithout checking that the value is not an Err.

\n
Safety
\n

Calling this method on an Err is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(unsafe { x.unwrap_unchecked() }, 2);
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nunsafe { x.unwrap_unchecked(); } // Undefined behavior!
\n
1.58.0 · source

pub unsafe fn unwrap_err_unchecked(self) -> E

Returns the contained Err value, consuming the self value,\nwithout checking that the value is not an Ok.

\n
Safety
\n

Calling this method on an Ok is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nunsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(unsafe { x.unwrap_err_unchecked() }, \"emergency failure\");
\n
",0,"anyhow::Result"],["
source§

impl<T, E> Result<&T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"anyhow::Result"],["
source§

impl<T, E> Result<&mut T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&mut T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&mut T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"anyhow::Result"],["
source§

impl<T, E> Result<Option<T>, E>

1.33.0 (const: unstable) · source

pub fn transpose(self) -> Option<Result<T, E>>

Transposes a Result of an Option into an Option of a Result.

\n

Ok(None) will be mapped to None.\nOk(Some(_)) and Err(_) will be mapped to Some(Ok(_)) and Some(Err(_)).

\n
Examples
\n
#[derive(Debug, Eq, PartialEq)]\nstruct SomeErr;\n\nlet x: Result<Option<i32>, SomeErr> = Ok(Some(5));\nlet y: Option<Result<i32, SomeErr>> = Some(Ok(5));\nassert_eq!(x.transpose(), y);
\n
",0,"anyhow::Result"],["
source§

impl<T, E> Result<Result<T, E>, E>

source

pub fn flatten(self) -> Result<T, E>

🔬This is a nightly-only experimental API. (result_flattening)

Converts from Result<Result<T, E>, E> to Result<T, E>

\n
Examples
\n
#![feature(result_flattening)]\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Ok(\"hello\"));\nassert_eq!(Ok(\"hello\"), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Err(6));\nassert_eq!(Err(6), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Err(6);\nassert_eq!(Err(6), x.flatten());
\n

Flattening only removes one level of nesting at a time:

\n\n
#![feature(result_flattening)]\nlet x: Result<Result<Result<&'static str, u32>, u32>, u32> = Ok(Ok(Ok(\"hello\")));\nassert_eq!(Ok(Ok(\"hello\")), x.flatten());\nassert_eq!(Ok(\"hello\"), x.flatten().flatten());
\n
",0,"anyhow::Result"],["
source§

impl<T, E> Try for Result<T, E>

§

type Output = T

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value produced by ? when not short-circuiting.
§

type Residual = Result<Infallible, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value passed to FromResidual::from_residual\nas part of ? when short-circuiting. Read more
source§

fn from_output(output: <Result<T, E> as Try>::Output) -> Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from its Output type. Read more
source§

fn branch(\n self\n) -> ControlFlow<<Result<T, E> as Try>::Residual, <Result<T, E> as Try>::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)
Used in ? to decide whether the operator should produce a value\n(because this returned ControlFlow::Continue)\nor propagate a value back to the caller\n(because this returned ControlFlow::Break). Read more
","Try","anyhow::Result"],["
1.16.0 · source§

impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
where\n T: Sum<U>,

source§

fn sum<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the sum of all elements is returned.

\n
Examples
\n

This sums up every integer in a vector, rejecting the sum if a negative\nelement is encountered:

\n\n
let f = |&x: &i32| if x < 0 { Err(\"Negative element found\") } else { Ok(x) };\nlet v = vec![1, 2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Ok(3));\nlet v = vec![1, -2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Err(\"Negative element found\"));
\n
","Sum>","anyhow::Result"],["
1.0.0 · source§

impl<T, E> Debug for Result<T, E>
where\n T: Debug,\n E: Debug,

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
","Debug","anyhow::Result"],["
1.0.0 · source§

impl<T, E> Clone for Result<T, E>
where\n T: Clone,\n E: Clone,

source§

fn clone(&self) -> Result<T, E>

Returns a copy of the value. Read more
source§

fn clone_from(&mut self, source: &Result<T, E>)

Performs copy-assignment from source. Read more
","Clone","anyhow::Result"],["
1.0.0 · source§

impl<T, E> StructuralEq for Result<T, E>

","StructuralEq","anyhow::Result"],["
1.16.0 · source§

impl<T, U, E> Product<Result<U, E>> for Result<T, E>
where\n T: Product<U>,

source§

fn product<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the product of all elements is returned.

\n
Examples
\n

This multiplies each number in a vector of strings,\nif a string could not be parsed the operation returns Err:

\n\n
let nums = vec![\"5\", \"10\", \"1\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert_eq!(total, Ok(100));\nlet nums = vec![\"5\", \"10\", \"one\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert!(total.is_err());
\n
","Product>","anyhow::Result"],["
1.0.0 · source§

impl<T, E> Eq for Result<T, E>
where\n T: Eq,\n E: Eq,

","Eq","anyhow::Result"],["
1.0.0 · source§

impl<T, E> Ord for Result<T, E>
where\n T: Ord,\n E: Ord,

source§

fn cmp(&self, other: &Result<T, E>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Self
where\n Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
","Ord","anyhow::Result"],["
source§

impl<T, E> Residual<T> for Result<Infallible, E>

§

type TryType = Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2_residual)
The “return” type of this meta-function.
","Residual","anyhow::Result"],["
1.0.0 · source§

impl<T, E> PartialEq for Result<T, E>
where\n T: PartialEq,\n E: PartialEq,

source§

fn eq(&self, other: &Result<T, E>) -> bool

This method tests for self and other values to be equal, and is used\nby ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always\nsufficient, and should not be overridden without very good reason.
","PartialEq","anyhow::Result"],["
1.0.0 · source§

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>
where\n V: FromIterator<A>,

source§

fn from_iter<I>(iter: I) -> Result<V, E>
where\n I: IntoIterator<Item = Result<A, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err occur, a\ncontainer with the values of each Result is returned.

\n

Here is an example which increments every integer in a vector,\nchecking for overflow:

\n\n
let v = vec![1, 2];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_add(1).ok_or(\"Overflow!\")\n).collect();\nassert_eq!(res, Ok(vec![2, 3]));
\n

Here is another example that tries to subtract one from another list\nof integers, this time checking for underflow:

\n\n
let v = vec![1, 2, 0];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_sub(1).ok_or(\"Underflow!\")\n).collect();\nassert_eq!(res, Err(\"Underflow!\"));
\n

Here is a variation on the previous example, showing that no\nfurther elements are taken from iter after the first Err.

\n\n
let v = vec![3, 2, 1, 10];\nlet mut shared = 0;\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32| {\n    shared += x;\n    x.checked_sub(2).ok_or(\"Underflow!\")\n}).collect();\nassert_eq!(res, Err(\"Underflow!\"));\nassert_eq!(shared, 6);
\n

Since the third element caused an underflow, no further elements were taken,\nso the final value of shared is 6 (= 3 + 2 + 1), not 16.

\n
","FromIterator>","anyhow::Result"],["
1.0.0 · source§

impl<T, E> StructuralPartialEq for Result<T, E>

","StructuralPartialEq","anyhow::Result"],["
1.0.0 · source§

impl<T, E> Copy for Result<T, E>
where\n T: Copy,\n E: Copy,

","Copy","anyhow::Result"],["
1.0.0 · source§

impl<T, E> Hash for Result<T, E>
where\n T: Hash,\n E: Hash,

source§

fn hash<__H>(&self, state: &mut __H)
where\n __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)
where\n H: Hasher,\n Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
","Hash","anyhow::Result"],["
1.0.0 · source§

impl<T, E> IntoIterator for Result<T, E>

source§

fn into_iter(self) -> IntoIter<T>

Returns a consuming iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(5);\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, [5]);\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, []);
\n
§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
","IntoIterator","anyhow::Result"],["
1.0.0 · source§

impl<T, E> PartialOrd for Result<T, E>
where\n T: PartialOrd,\n E: PartialOrd,

source§

fn partial_cmp(&self, other: &Result<T, E>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <=\noperator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >=\noperator. Read more
","PartialOrd","anyhow::Result"],["
source§

impl<T, E, F> FromResidual<Yeet<E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(_: Yeet<E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","anyhow::Result"],["
source§

impl<T, E, F> FromResidual<Result<Infallible, E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(residual: Result<Infallible, E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","anyhow::Result"],["
1.61.0 · source§

impl<T, E> Termination for Result<T, E>
where\n T: Termination,\n E: Debug,

source§

fn report(self) -> ExitCode

Is called to get the representation of the value as status code.\nThis status code is returned to the operating system.
","Termination","anyhow::Result"],["
source§

impl From<StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From","anyhow::Result"],["
source§

impl From<&StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: &StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From<&StreamResult>","anyhow::Result"],["
source§

impl<T, E> Context<T, E> for Result<T, E>
where\n E: StdError + Send + Sync + 'static,

source§

fn context<C>(self, context: C) -> Result<T, Error>
where\n C: Display + Send + Sync + 'static,

Wrap the error value with additional context.
source§

fn with_context<C, F>(self, context: F) -> Result<T, Error>
where\n C: Display + Send + Sync + 'static,\n F: FnOnce() -> C,

Wrap the error value with additional context that is evaluated lazily\nonly once an error does occur.
","Context","anyhow::Result"]], "cargo_metadata":[["
source§

impl<T, E> Result<T, E>

1.0.0 (const: 1.48.0) · source

pub const fn is_ok(&self) -> bool

Returns true if the result is Ok.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_ok(), true);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_ok(), false);
\n
1.70.0 · source

pub fn is_ok_and(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the result is Ok and the value inside of it matches a predicate.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.is_ok_and(|x| x > 1), true);\n\nlet x: Result<u32, &str> = Ok(0);\nassert_eq!(x.is_ok_and(|x| x > 1), false);\n\nlet x: Result<u32, &str> = Err(\"hey\");\nassert_eq!(x.is_ok_and(|x| x > 1), false);
\n
1.0.0 (const: 1.48.0) · source

pub const fn is_err(&self) -> bool

Returns true if the result is Err.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_err(), false);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_err(), true);
\n
1.70.0 · source

pub fn is_err_and(self, f: impl FnOnce(E) -> bool) -> bool

Returns true if the result is Err and the value inside of it matches a predicate.

\n
Examples
\n
use std::io::{Error, ErrorKind};\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), true);\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);\n\nlet x: Result<u32, Error> = Ok(123);\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);
\n
1.0.0 · source

pub fn ok(self) -> Option<T>

Converts from Result<T, E> to Option<T>.

\n

Converts self into an Option<T>, consuming self,\nand discarding the error, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.ok(), Some(2));\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.ok(), None);
\n
1.0.0 · source

pub fn err(self) -> Option<E>

Converts from Result<T, E> to Option<E>.

\n

Converts self into an Option<E>, consuming self,\nand discarding the success value, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.err(), None);\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.err(), Some(\"Nothing here\"));
\n
1.0.0 (const: 1.48.0) · source

pub const fn as_ref(&self) -> Result<&T, &E>

Converts from &Result<T, E> to Result<&T, &E>.

\n

Produces a new Result, containing a reference\ninto the original, leaving the original in place.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.as_ref(), Ok(&2));\n\nlet x: Result<u32, &str> = Err(\"Error\");\nassert_eq!(x.as_ref(), Err(&\"Error\"));
\n
1.0.0 (const: unstable) · source

pub fn as_mut(&mut self) -> Result<&mut T, &mut E>

Converts from &mut Result<T, E> to Result<&mut T, &mut E>.

\n
Examples
\n
fn mutate(r: &mut Result<i32, i32>) {\n    match r.as_mut() {\n        Ok(v) => *v = 42,\n        Err(e) => *e = 0,\n    }\n}\n\nlet mut x: Result<i32, i32> = Ok(2);\nmutate(&mut x);\nassert_eq!(x.unwrap(), 42);\n\nlet mut x: Result<i32, i32> = Err(13);\nmutate(&mut x);\nassert_eq!(x.unwrap_err(), 0);
\n
1.0.0 · source

pub fn map<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> U,

Maps a Result<T, E> to Result<U, E> by applying a function to a\ncontained Ok value, leaving an Err value untouched.

\n

This function can be used to compose the results of two functions.

\n
Examples
\n

Print the numbers on each line of a string multiplied by two.

\n\n
let line = \"1\\n2\\n3\\n4\\n\";\n\nfor num in line.lines() {\n    match num.parse::<i32>().map(|i| i * 2) {\n        Ok(n) => println!(\"{n}\"),\n        Err(..) => {}\n    }\n}
\n
1.41.0 · source

pub fn map_or<U, F>(self, default: U, f: F) -> U
where\n F: FnOnce(T) -> U,

Returns the provided default (if Err), or\napplies a function to the contained value (if Ok).

\n

Arguments passed to map_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use map_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let x: Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or(42, |v| v.len()), 3);\n\nlet x: Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or(42, |v| v.len()), 42);
\n
1.41.0 · source

pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
where\n D: FnOnce(E) -> U,\n F: FnOnce(T) -> U,

Maps a Result<T, E> to U by applying fallback function default to\na contained Err value, or function f to a contained Ok value.

\n

This function can be used to unpack a successful result\nwhile handling an error.

\n
Examples
\n
let k = 21;\n\nlet x : Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 3);\n\nlet x : Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 42);
\n
1.0.0 · source

pub fn map_err<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> F,

Maps a Result<T, E> to Result<T, F> by applying a function to a\ncontained Err value, leaving an Ok value untouched.

\n

This function can be used to pass through a successful result while handling\nan error.

\n
Examples
\n
fn stringify(x: u32) -> String { format!(\"error code: {x}\") }\n\nlet x: Result<u32, u32> = Ok(2);\nassert_eq!(x.map_err(stringify), Ok(2));\n\nlet x: Result<u32, u32> = Err(13);\nassert_eq!(x.map_err(stringify), Err(\"error code: 13\".to_string()));
\n
1.76.0 · source

pub fn inspect<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&T),

Calls the provided closure with a reference to the contained value (if Ok).

\n
Examples
\n
let x: u8 = \"4\"\n    .parse::<u8>()\n    .inspect(|x| println!(\"original: {x}\"))\n    .map(|x| x.pow(3))\n    .expect(\"failed to parse number\");
\n
1.76.0 · source

pub fn inspect_err<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&E),

Calls the provided closure with a reference to the contained error (if Err).

\n
Examples
\n
use std::{fs, io};\n\nfn read() -> io::Result<String> {\n    fs::read_to_string(\"address.txt\")\n        .inspect_err(|e| eprintln!(\"failed to read file: {e}\"))\n}
\n
1.47.0 · source

pub fn as_deref(&self) -> Result<&<T as Deref>::Target, &E>
where\n T: Deref,

Converts from Result<T, E> (or &Result<T, E>) to Result<&<T as Deref>::Target, &E>.

\n

Coerces the Ok variant of the original Result via Deref\nand returns the new Result.

\n
Examples
\n
let x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&str, &u32> = Ok(\"hello\");\nassert_eq!(x.as_deref(), y);\n\nlet x: Result<String, u32> = Err(42);\nlet y: Result<&str, &u32> = Err(&42);\nassert_eq!(x.as_deref(), y);
\n
1.47.0 · source

pub fn as_deref_mut(&mut self) -> Result<&mut <T as Deref>::Target, &mut E>
where\n T: DerefMut,

Converts from Result<T, E> (or &mut Result<T, E>) to Result<&mut <T as DerefMut>::Target, &mut E>.

\n

Coerces the Ok variant of the original Result via DerefMut\nand returns the new Result.

\n
Examples
\n
let mut s = \"HELLO\".to_string();\nlet mut x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&mut str, &mut u32> = Ok(&mut s);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);\n\nlet mut i = 42;\nlet mut x: Result<String, u32> = Err(42);\nlet y: Result<&mut str, &mut u32> = Err(&mut i);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
\n
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(7);\nassert_eq!(x.iter().next(), Some(&7));\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter().next(), None);
\n
1.0.0 · source

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns a mutable iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let mut x: Result<u32, &str> = Ok(7);\nmatch x.iter_mut().next() {\n    Some(v) => *v = 40,\n    None => {},\n}\nassert_eq!(x, Ok(40));\n\nlet mut x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter_mut().next(), None);
\n
1.4.0 · source

pub fn expect(self, msg: &str) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message including the\npassed message, and the content of the Err.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.expect(\"Testing expect\"); // panics with `Testing expect: emergency failure`
\n
Recommended Message Style
\n

We recommend that expect messages are used to describe the reason you\nexpect the Result should be Ok.

\n\n
ⓘ
let path = std::env::var(\"IMPORTANT_PATH\")\n    .expect(\"env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`\");
\n

Hint: If you’re having trouble remembering how to phrase expect\nerror messages remember to focus on the word “should” as in “env\nvariable should be set by blah” or “the given binary should be available\nand executable by the current user”.

\n

For more detail on expect message styles and the reasoning behind our recommendation please\nrefer to the section on “Common Message\nStyles” in the\nstd::error module docs.

\n
1.0.0 · source

pub fn unwrap(self) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message provided by the\nErr’s value.

\n
Examples
\n

Basic usage:

\n\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.unwrap(), 2);
\n\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.unwrap(); // panics with `emergency failure`
\n
1.16.0 · source

pub fn unwrap_or_default(self) -> T
where\n T: Default,

Returns the contained Ok value or a default

\n

Consumes the self argument then, if Ok, returns the contained\nvalue, otherwise if Err, returns the default value for that\ntype.

\n
Examples
\n

Converts a string to an integer, turning poorly-formed strings\ninto 0 (the default value for integers). parse converts\na string to any other type that implements FromStr, returning an\nErr on error.

\n\n
let good_year_from_input = \"1909\";\nlet bad_year_from_input = \"190blarg\";\nlet good_year = good_year_from_input.parse().unwrap_or_default();\nlet bad_year = bad_year_from_input.parse().unwrap_or_default();\n\nassert_eq!(1909, good_year);\nassert_eq!(0, bad_year);
\n
1.17.0 · source

pub fn expect_err(self, msg: &str) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a panic message including the\npassed message, and the content of the Ok.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(10);\nx.expect_err(\"Testing expect_err\"); // panics with `Testing expect_err: 10`
\n
1.0.0 · source

pub fn unwrap_err(self) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a custom panic message provided\nby the Ok’s value.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(2);\nx.unwrap_err(); // panics with `2`
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(x.unwrap_err(), \"emergency failure\");
\n
source

pub fn into_ok(self) -> T
where\n E: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Ok value, but never panics.

\n

Unlike unwrap, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap as a maintainability safeguard that will fail\nto compile if the error type of the Result is later changed\nto an error that can actually occur.

\n
Examples
\n
\nfn only_good_news() -> Result<String, !> {\n    Ok(\"this is fine\".into())\n}\n\nlet s: String = only_good_news().into_ok();\nprintln!(\"{s}\");
\n
source

pub fn into_err(self) -> E
where\n T: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Err value, but never panics.

\n

Unlike unwrap_err, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap_err as a maintainability safeguard that will fail\nto compile if the ok type of the Result is later changed\nto a type that can actually occur.

\n
Examples
\n
\nfn only_bad_news() -> Result<!, String> {\n    Err(\"Oops, it failed\".into())\n}\n\nlet error: String = only_bad_news().into_err();\nprintln!(\"{error}\");
\n
1.0.0 · source

pub fn and<U>(self, res: Result<U, E>) -> Result<U, E>

Returns res if the result is Ok, otherwise returns the Err value of self.

\n

Arguments passed to and are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use and_then, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<&str, &str> = Ok(\"foo\");\nassert_eq!(x.and(y), Err(\"early error\"));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"not a 2\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Ok(\"different result type\");\nassert_eq!(x.and(y), Ok(\"different result type\"));
\n
1.0.0 · source

pub fn and_then<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> Result<U, E>,

Calls op if the result is Ok, otherwise returns the Err value of self.

\n

This function can be used for control flow based on Result values.

\n
Examples
\n
fn sq_then_to_string(x: u32) -> Result<String, &'static str> {\n    x.checked_mul(x).map(|sq| sq.to_string()).ok_or(\"overflowed\")\n}\n\nassert_eq!(Ok(2).and_then(sq_then_to_string), Ok(4.to_string()));\nassert_eq!(Ok(1_000_000).and_then(sq_then_to_string), Err(\"overflowed\"));\nassert_eq!(Err(\"not a number\").and_then(sq_then_to_string), Err(\"not a number\"));
\n

Often used to chain fallible operations that may return Err.

\n\n
use std::{io::ErrorKind, path::Path};\n\n// Note: on Windows \"/\" maps to \"C:\\\"\nlet root_modified_time = Path::new(\"/\").metadata().and_then(|md| md.modified());\nassert!(root_modified_time.is_ok());\n\nlet should_fail = Path::new(\"/bad/path\").metadata().and_then(|md| md.modified());\nassert!(should_fail.is_err());\nassert_eq!(should_fail.unwrap_err().kind(), ErrorKind::NotFound);
\n
1.0.0 · source

pub fn or<F>(self, res: Result<T, F>) -> Result<T, F>

Returns res if the result is Err, otherwise returns the Ok value of self.

\n

Arguments passed to or are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use or_else, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<u32, &str> = Ok(2);\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Ok(100);\nassert_eq!(x.or(y), Ok(2));
\n
1.0.0 · source

pub fn or_else<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> Result<T, F>,

Calls op if the result is Err, otherwise returns the Ok value of self.

\n

This function can be used for control flow based on result values.

\n
Examples
\n
fn sq(x: u32) -> Result<u32, u32> { Ok(x * x) }\nfn err(x: u32) -> Result<u32, u32> { Err(x) }\n\nassert_eq!(Ok(2).or_else(sq).or_else(sq), Ok(2));\nassert_eq!(Ok(2).or_else(err).or_else(sq), Ok(2));\nassert_eq!(Err(3).or_else(sq).or_else(err), Ok(9));\nassert_eq!(Err(3).or_else(err).or_else(err), Err(3));
\n
1.0.0 · source

pub fn unwrap_or(self, default: T) -> T

Returns the contained Ok value or a provided default.

\n

Arguments passed to unwrap_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use unwrap_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let default = 2;\nlet x: Result<u32, &str> = Ok(9);\nassert_eq!(x.unwrap_or(default), 9);\n\nlet x: Result<u32, &str> = Err(\"error\");\nassert_eq!(x.unwrap_or(default), default);
\n
1.0.0 · source

pub fn unwrap_or_else<F>(self, op: F) -> T
where\n F: FnOnce(E) -> T,

Returns the contained Ok value or computes it from a closure.

\n
Examples
\n
fn count(x: &str) -> usize { x.len() }\n\nassert_eq!(Ok(2).unwrap_or_else(count), 2);\nassert_eq!(Err(\"foo\").unwrap_or_else(count), 3);
\n
1.58.0 · source

pub unsafe fn unwrap_unchecked(self) -> T

Returns the contained Ok value, consuming the self value,\nwithout checking that the value is not an Err.

\n
Safety
\n

Calling this method on an Err is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(unsafe { x.unwrap_unchecked() }, 2);
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nunsafe { x.unwrap_unchecked(); } // Undefined behavior!
\n
1.58.0 · source

pub unsafe fn unwrap_err_unchecked(self) -> E

Returns the contained Err value, consuming the self value,\nwithout checking that the value is not an Ok.

\n
Safety
\n

Calling this method on an Ok is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nunsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(unsafe { x.unwrap_err_unchecked() }, \"emergency failure\");
\n
",0,"cargo_metadata::errors::Result"],["
source§

impl<T, E> Result<&T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"cargo_metadata::errors::Result"],["
source§

impl<T, E> Result<&mut T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&mut T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&mut T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"cargo_metadata::errors::Result"],["
source§

impl<T, E> Result<Option<T>, E>

1.33.0 (const: unstable) · source

pub fn transpose(self) -> Option<Result<T, E>>

Transposes a Result of an Option into an Option of a Result.

\n

Ok(None) will be mapped to None.\nOk(Some(_)) and Err(_) will be mapped to Some(Ok(_)) and Some(Err(_)).

\n
Examples
\n
#[derive(Debug, Eq, PartialEq)]\nstruct SomeErr;\n\nlet x: Result<Option<i32>, SomeErr> = Ok(Some(5));\nlet y: Option<Result<i32, SomeErr>> = Some(Ok(5));\nassert_eq!(x.transpose(), y);
\n
",0,"cargo_metadata::errors::Result"],["
source§

impl<T, E> Result<Result<T, E>, E>

source

pub fn flatten(self) -> Result<T, E>

🔬This is a nightly-only experimental API. (result_flattening)

Converts from Result<Result<T, E>, E> to Result<T, E>

\n
Examples
\n
#![feature(result_flattening)]\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Ok(\"hello\"));\nassert_eq!(Ok(\"hello\"), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Err(6));\nassert_eq!(Err(6), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Err(6);\nassert_eq!(Err(6), x.flatten());
\n

Flattening only removes one level of nesting at a time:

\n\n
#![feature(result_flattening)]\nlet x: Result<Result<Result<&'static str, u32>, u32>, u32> = Ok(Ok(Ok(\"hello\")));\nassert_eq!(Ok(Ok(\"hello\")), x.flatten());\nassert_eq!(Ok(\"hello\"), x.flatten().flatten());
\n
",0,"cargo_metadata::errors::Result"],["
1.61.0 · source§

impl<T, E> Termination for Result<T, E>
where\n T: Termination,\n E: Debug,

source§

fn report(self) -> ExitCode

Is called to get the representation of the value as status code.\nThis status code is returned to the operating system.
","Termination","cargo_metadata::errors::Result"],["
source§

impl<T, E> Try for Result<T, E>

§

type Output = T

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value produced by ? when not short-circuiting.
§

type Residual = Result<Infallible, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value passed to FromResidual::from_residual\nas part of ? when short-circuiting. Read more
source§

fn from_output(output: <Result<T, E> as Try>::Output) -> Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from its Output type. Read more
source§

fn branch(\n self\n) -> ControlFlow<<Result<T, E> as Try>::Residual, <Result<T, E> as Try>::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)
Used in ? to decide whether the operator should produce a value\n(because this returned ControlFlow::Continue)\nor propagate a value back to the caller\n(because this returned ControlFlow::Break). Read more
","Try","cargo_metadata::errors::Result"],["
1.16.0 · source§

impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
where\n T: Sum<U>,

source§

fn sum<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the sum of all elements is returned.

\n
Examples
\n

This sums up every integer in a vector, rejecting the sum if a negative\nelement is encountered:

\n\n
let f = |&x: &i32| if x < 0 { Err(\"Negative element found\") } else { Ok(x) };\nlet v = vec![1, 2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Ok(3));\nlet v = vec![1, -2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Err(\"Negative element found\"));
\n
","Sum>","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> Debug for Result<T, E>
where\n T: Debug,\n E: Debug,

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
","Debug","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> Clone for Result<T, E>
where\n T: Clone,\n E: Clone,

source§

fn clone(&self) -> Result<T, E>

Returns a copy of the value. Read more
source§

fn clone_from(&mut self, source: &Result<T, E>)

Performs copy-assignment from source. Read more
","Clone","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> StructuralEq for Result<T, E>

","StructuralEq","cargo_metadata::errors::Result"],["
1.16.0 · source§

impl<T, U, E> Product<Result<U, E>> for Result<T, E>
where\n T: Product<U>,

source§

fn product<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the product of all elements is returned.

\n
Examples
\n

This multiplies each number in a vector of strings,\nif a string could not be parsed the operation returns Err:

\n\n
let nums = vec![\"5\", \"10\", \"1\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert_eq!(total, Ok(100));\nlet nums = vec![\"5\", \"10\", \"one\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert!(total.is_err());
\n
","Product>","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> Eq for Result<T, E>
where\n T: Eq,\n E: Eq,

","Eq","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> Ord for Result<T, E>
where\n T: Ord,\n E: Ord,

source§

fn cmp(&self, other: &Result<T, E>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Self
where\n Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
","Ord","cargo_metadata::errors::Result"],["
source§

impl<T, E> Residual<T> for Result<Infallible, E>

§

type TryType = Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2_residual)
The “return” type of this meta-function.
","Residual","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> PartialEq for Result<T, E>
where\n T: PartialEq,\n E: PartialEq,

source§

fn eq(&self, other: &Result<T, E>) -> bool

This method tests for self and other values to be equal, and is used\nby ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always\nsufficient, and should not be overridden without very good reason.
","PartialEq","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>
where\n V: FromIterator<A>,

source§

fn from_iter<I>(iter: I) -> Result<V, E>
where\n I: IntoIterator<Item = Result<A, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err occur, a\ncontainer with the values of each Result is returned.

\n

Here is an example which increments every integer in a vector,\nchecking for overflow:

\n\n
let v = vec![1, 2];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_add(1).ok_or(\"Overflow!\")\n).collect();\nassert_eq!(res, Ok(vec![2, 3]));
\n

Here is another example that tries to subtract one from another list\nof integers, this time checking for underflow:

\n\n
let v = vec![1, 2, 0];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_sub(1).ok_or(\"Underflow!\")\n).collect();\nassert_eq!(res, Err(\"Underflow!\"));
\n

Here is a variation on the previous example, showing that no\nfurther elements are taken from iter after the first Err.

\n\n
let v = vec![3, 2, 1, 10];\nlet mut shared = 0;\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32| {\n    shared += x;\n    x.checked_sub(2).ok_or(\"Underflow!\")\n}).collect();\nassert_eq!(res, Err(\"Underflow!\"));\nassert_eq!(shared, 6);
\n

Since the third element caused an underflow, no further elements were taken,\nso the final value of shared is 6 (= 3 + 2 + 1), not 16.

\n
","FromIterator>","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> StructuralPartialEq for Result<T, E>

","StructuralPartialEq","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> Copy for Result<T, E>
where\n T: Copy,\n E: Copy,

","Copy","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> Hash for Result<T, E>
where\n T: Hash,\n E: Hash,

source§

fn hash<__H>(&self, state: &mut __H)
where\n __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)
where\n H: Hasher,\n Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
","Hash","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> IntoIterator for Result<T, E>

source§

fn into_iter(self) -> IntoIter<T>

Returns a consuming iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(5);\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, [5]);\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, []);
\n
§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
","IntoIterator","cargo_metadata::errors::Result"],["
1.0.0 · source§

impl<T, E> PartialOrd for Result<T, E>
where\n T: PartialOrd,\n E: PartialOrd,

source§

fn partial_cmp(&self, other: &Result<T, E>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <=\noperator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >=\noperator. Read more
","PartialOrd","cargo_metadata::errors::Result"],["
source§

impl<T, E, F> FromResidual<Yeet<E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(_: Yeet<E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","cargo_metadata::errors::Result"],["
source§

impl<T, E, F> FromResidual<Result<Infallible, E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(residual: Result<Infallible, E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","cargo_metadata::errors::Result"],["
source§

impl<'de, T, E> Deserialize<'de> for Result<T, E>
where\n T: Deserialize<'de>,\n E: Deserialize<'de>,

source§

fn deserialize<D>(\n deserializer: D\n) -> Result<Result<T, E>, <D as Deserializer<'de>>::Error>
where\n D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
","Deserialize<'de>","cargo_metadata::errors::Result"],["
source§

impl<T, E> Serialize for Result<T, E>
where\n T: Serialize,\n E: Serialize,

source§

fn serialize<S>(\n &self,\n serializer: S\n) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>
where\n S: Serializer,

Serialize this value into the given Serde serializer. Read more
","Serialize","cargo_metadata::errors::Result"]], "clap":[["
source§

impl<T, E> Result<T, E>

1.0.0 (const: 1.48.0) · source

pub const fn is_ok(&self) -> bool

Returns true if the result is Ok.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_ok(), true);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_ok(), false);
\n
1.70.0 · source

pub fn is_ok_and(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the result is Ok and the value inside of it matches a predicate.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.is_ok_and(|x| x > 1), true);\n\nlet x: Result<u32, &str> = Ok(0);\nassert_eq!(x.is_ok_and(|x| x > 1), false);\n\nlet x: Result<u32, &str> = Err(\"hey\");\nassert_eq!(x.is_ok_and(|x| x > 1), false);
\n
1.0.0 (const: 1.48.0) · source

pub const fn is_err(&self) -> bool

Returns true if the result is Err.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_err(), false);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_err(), true);
\n
1.70.0 · source

pub fn is_err_and(self, f: impl FnOnce(E) -> bool) -> bool

Returns true if the result is Err and the value inside of it matches a predicate.

\n
Examples
\n
use std::io::{Error, ErrorKind};\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), true);\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);\n\nlet x: Result<u32, Error> = Ok(123);\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);
\n
1.0.0 · source

pub fn ok(self) -> Option<T>

Converts from Result<T, E> to Option<T>.

\n

Converts self into an Option<T>, consuming self,\nand discarding the error, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.ok(), Some(2));\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.ok(), None);
\n
1.0.0 · source

pub fn err(self) -> Option<E>

Converts from Result<T, E> to Option<E>.

\n

Converts self into an Option<E>, consuming self,\nand discarding the success value, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.err(), None);\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.err(), Some(\"Nothing here\"));
\n
1.0.0 (const: 1.48.0) · source

pub const fn as_ref(&self) -> Result<&T, &E>

Converts from &Result<T, E> to Result<&T, &E>.

\n

Produces a new Result, containing a reference\ninto the original, leaving the original in place.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.as_ref(), Ok(&2));\n\nlet x: Result<u32, &str> = Err(\"Error\");\nassert_eq!(x.as_ref(), Err(&\"Error\"));
\n
1.0.0 (const: unstable) · source

pub fn as_mut(&mut self) -> Result<&mut T, &mut E>

Converts from &mut Result<T, E> to Result<&mut T, &mut E>.

\n
Examples
\n
fn mutate(r: &mut Result<i32, i32>) {\n    match r.as_mut() {\n        Ok(v) => *v = 42,\n        Err(e) => *e = 0,\n    }\n}\n\nlet mut x: Result<i32, i32> = Ok(2);\nmutate(&mut x);\nassert_eq!(x.unwrap(), 42);\n\nlet mut x: Result<i32, i32> = Err(13);\nmutate(&mut x);\nassert_eq!(x.unwrap_err(), 0);
\n
1.0.0 · source

pub fn map<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> U,

Maps a Result<T, E> to Result<U, E> by applying a function to a\ncontained Ok value, leaving an Err value untouched.

\n

This function can be used to compose the results of two functions.

\n
Examples
\n

Print the numbers on each line of a string multiplied by two.

\n\n
let line = \"1\\n2\\n3\\n4\\n\";\n\nfor num in line.lines() {\n    match num.parse::<i32>().map(|i| i * 2) {\n        Ok(n) => println!(\"{n}\"),\n        Err(..) => {}\n    }\n}
\n
1.41.0 · source

pub fn map_or<U, F>(self, default: U, f: F) -> U
where\n F: FnOnce(T) -> U,

Returns the provided default (if Err), or\napplies a function to the contained value (if Ok).

\n

Arguments passed to map_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use map_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let x: Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or(42, |v| v.len()), 3);\n\nlet x: Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or(42, |v| v.len()), 42);
\n
1.41.0 · source

pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
where\n D: FnOnce(E) -> U,\n F: FnOnce(T) -> U,

Maps a Result<T, E> to U by applying fallback function default to\na contained Err value, or function f to a contained Ok value.

\n

This function can be used to unpack a successful result\nwhile handling an error.

\n
Examples
\n
let k = 21;\n\nlet x : Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 3);\n\nlet x : Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 42);
\n
1.0.0 · source

pub fn map_err<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> F,

Maps a Result<T, E> to Result<T, F> by applying a function to a\ncontained Err value, leaving an Ok value untouched.

\n

This function can be used to pass through a successful result while handling\nan error.

\n
Examples
\n
fn stringify(x: u32) -> String { format!(\"error code: {x}\") }\n\nlet x: Result<u32, u32> = Ok(2);\nassert_eq!(x.map_err(stringify), Ok(2));\n\nlet x: Result<u32, u32> = Err(13);\nassert_eq!(x.map_err(stringify), Err(\"error code: 13\".to_string()));
\n
1.76.0 · source

pub fn inspect<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&T),

Calls the provided closure with a reference to the contained value (if Ok).

\n
Examples
\n
let x: u8 = \"4\"\n    .parse::<u8>()\n    .inspect(|x| println!(\"original: {x}\"))\n    .map(|x| x.pow(3))\n    .expect(\"failed to parse number\");
\n
1.76.0 · source

pub fn inspect_err<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&E),

Calls the provided closure with a reference to the contained error (if Err).

\n
Examples
\n
use std::{fs, io};\n\nfn read() -> io::Result<String> {\n    fs::read_to_string(\"address.txt\")\n        .inspect_err(|e| eprintln!(\"failed to read file: {e}\"))\n}
\n
1.47.0 · source

pub fn as_deref(&self) -> Result<&<T as Deref>::Target, &E>
where\n T: Deref,

Converts from Result<T, E> (or &Result<T, E>) to Result<&<T as Deref>::Target, &E>.

\n

Coerces the Ok variant of the original Result via Deref\nand returns the new Result.

\n
Examples
\n
let x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&str, &u32> = Ok(\"hello\");\nassert_eq!(x.as_deref(), y);\n\nlet x: Result<String, u32> = Err(42);\nlet y: Result<&str, &u32> = Err(&42);\nassert_eq!(x.as_deref(), y);
\n
1.47.0 · source

pub fn as_deref_mut(&mut self) -> Result<&mut <T as Deref>::Target, &mut E>
where\n T: DerefMut,

Converts from Result<T, E> (or &mut Result<T, E>) to Result<&mut <T as DerefMut>::Target, &mut E>.

\n

Coerces the Ok variant of the original Result via DerefMut\nand returns the new Result.

\n
Examples
\n
let mut s = \"HELLO\".to_string();\nlet mut x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&mut str, &mut u32> = Ok(&mut s);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);\n\nlet mut i = 42;\nlet mut x: Result<String, u32> = Err(42);\nlet y: Result<&mut str, &mut u32> = Err(&mut i);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
\n
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(7);\nassert_eq!(x.iter().next(), Some(&7));\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter().next(), None);
\n
1.0.0 · source

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns a mutable iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let mut x: Result<u32, &str> = Ok(7);\nmatch x.iter_mut().next() {\n    Some(v) => *v = 40,\n    None => {},\n}\nassert_eq!(x, Ok(40));\n\nlet mut x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter_mut().next(), None);
\n
1.4.0 · source

pub fn expect(self, msg: &str) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message including the\npassed message, and the content of the Err.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.expect(\"Testing expect\"); // panics with `Testing expect: emergency failure`
\n
Recommended Message Style
\n

We recommend that expect messages are used to describe the reason you\nexpect the Result should be Ok.

\n\n
ⓘ
let path = std::env::var(\"IMPORTANT_PATH\")\n    .expect(\"env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`\");
\n

Hint: If you’re having trouble remembering how to phrase expect\nerror messages remember to focus on the word “should” as in “env\nvariable should be set by blah” or “the given binary should be available\nand executable by the current user”.

\n

For more detail on expect message styles and the reasoning behind our recommendation please\nrefer to the section on “Common Message\nStyles” in the\nstd::error module docs.

\n
1.0.0 · source

pub fn unwrap(self) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message provided by the\nErr’s value.

\n
Examples
\n

Basic usage:

\n\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.unwrap(), 2);
\n\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.unwrap(); // panics with `emergency failure`
\n
1.16.0 · source

pub fn unwrap_or_default(self) -> T
where\n T: Default,

Returns the contained Ok value or a default

\n

Consumes the self argument then, if Ok, returns the contained\nvalue, otherwise if Err, returns the default value for that\ntype.

\n
Examples
\n

Converts a string to an integer, turning poorly-formed strings\ninto 0 (the default value for integers). parse converts\na string to any other type that implements FromStr, returning an\nErr on error.

\n\n
let good_year_from_input = \"1909\";\nlet bad_year_from_input = \"190blarg\";\nlet good_year = good_year_from_input.parse().unwrap_or_default();\nlet bad_year = bad_year_from_input.parse().unwrap_or_default();\n\nassert_eq!(1909, good_year);\nassert_eq!(0, bad_year);
\n
1.17.0 · source

pub fn expect_err(self, msg: &str) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a panic message including the\npassed message, and the content of the Ok.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(10);\nx.expect_err(\"Testing expect_err\"); // panics with `Testing expect_err: 10`
\n
1.0.0 · source

pub fn unwrap_err(self) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a custom panic message provided\nby the Ok’s value.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(2);\nx.unwrap_err(); // panics with `2`
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(x.unwrap_err(), \"emergency failure\");
\n
source

pub fn into_ok(self) -> T
where\n E: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Ok value, but never panics.

\n

Unlike unwrap, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap as a maintainability safeguard that will fail\nto compile if the error type of the Result is later changed\nto an error that can actually occur.

\n
Examples
\n
\nfn only_good_news() -> Result<String, !> {\n    Ok(\"this is fine\".into())\n}\n\nlet s: String = only_good_news().into_ok();\nprintln!(\"{s}\");
\n
source

pub fn into_err(self) -> E
where\n T: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Err value, but never panics.

\n

Unlike unwrap_err, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap_err as a maintainability safeguard that will fail\nto compile if the ok type of the Result is later changed\nto a type that can actually occur.

\n
Examples
\n
\nfn only_bad_news() -> Result<!, String> {\n    Err(\"Oops, it failed\".into())\n}\n\nlet error: String = only_bad_news().into_err();\nprintln!(\"{error}\");
\n
1.0.0 · source

pub fn and<U>(self, res: Result<U, E>) -> Result<U, E>

Returns res if the result is Ok, otherwise returns the Err value of self.

\n

Arguments passed to and are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use and_then, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<&str, &str> = Ok(\"foo\");\nassert_eq!(x.and(y), Err(\"early error\"));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"not a 2\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Ok(\"different result type\");\nassert_eq!(x.and(y), Ok(\"different result type\"));
\n
1.0.0 · source

pub fn and_then<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> Result<U, E>,

Calls op if the result is Ok, otherwise returns the Err value of self.

\n

This function can be used for control flow based on Result values.

\n
Examples
\n
fn sq_then_to_string(x: u32) -> Result<String, &'static str> {\n    x.checked_mul(x).map(|sq| sq.to_string()).ok_or(\"overflowed\")\n}\n\nassert_eq!(Ok(2).and_then(sq_then_to_string), Ok(4.to_string()));\nassert_eq!(Ok(1_000_000).and_then(sq_then_to_string), Err(\"overflowed\"));\nassert_eq!(Err(\"not a number\").and_then(sq_then_to_string), Err(\"not a number\"));
\n

Often used to chain fallible operations that may return Err.

\n\n
use std::{io::ErrorKind, path::Path};\n\n// Note: on Windows \"/\" maps to \"C:\\\"\nlet root_modified_time = Path::new(\"/\").metadata().and_then(|md| md.modified());\nassert!(root_modified_time.is_ok());\n\nlet should_fail = Path::new(\"/bad/path\").metadata().and_then(|md| md.modified());\nassert!(should_fail.is_err());\nassert_eq!(should_fail.unwrap_err().kind(), ErrorKind::NotFound);
\n
1.0.0 · source

pub fn or<F>(self, res: Result<T, F>) -> Result<T, F>

Returns res if the result is Err, otherwise returns the Ok value of self.

\n

Arguments passed to or are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use or_else, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<u32, &str> = Ok(2);\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Ok(100);\nassert_eq!(x.or(y), Ok(2));
\n
1.0.0 · source

pub fn or_else<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> Result<T, F>,

Calls op if the result is Err, otherwise returns the Ok value of self.

\n

This function can be used for control flow based on result values.

\n
Examples
\n
fn sq(x: u32) -> Result<u32, u32> { Ok(x * x) }\nfn err(x: u32) -> Result<u32, u32> { Err(x) }\n\nassert_eq!(Ok(2).or_else(sq).or_else(sq), Ok(2));\nassert_eq!(Ok(2).or_else(err).or_else(sq), Ok(2));\nassert_eq!(Err(3).or_else(sq).or_else(err), Ok(9));\nassert_eq!(Err(3).or_else(err).or_else(err), Err(3));
\n
1.0.0 · source

pub fn unwrap_or(self, default: T) -> T

Returns the contained Ok value or a provided default.

\n

Arguments passed to unwrap_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use unwrap_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let default = 2;\nlet x: Result<u32, &str> = Ok(9);\nassert_eq!(x.unwrap_or(default), 9);\n\nlet x: Result<u32, &str> = Err(\"error\");\nassert_eq!(x.unwrap_or(default), default);
\n
1.0.0 · source

pub fn unwrap_or_else<F>(self, op: F) -> T
where\n F: FnOnce(E) -> T,

Returns the contained Ok value or computes it from a closure.

\n
Examples
\n
fn count(x: &str) -> usize { x.len() }\n\nassert_eq!(Ok(2).unwrap_or_else(count), 2);\nassert_eq!(Err(\"foo\").unwrap_or_else(count), 3);
\n
1.58.0 · source

pub unsafe fn unwrap_unchecked(self) -> T

Returns the contained Ok value, consuming the self value,\nwithout checking that the value is not an Err.

\n
Safety
\n

Calling this method on an Err is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(unsafe { x.unwrap_unchecked() }, 2);
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nunsafe { x.unwrap_unchecked(); } // Undefined behavior!
\n
1.58.0 · source

pub unsafe fn unwrap_err_unchecked(self) -> E

Returns the contained Err value, consuming the self value,\nwithout checking that the value is not an Ok.

\n
Safety
\n

Calling this method on an Ok is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nunsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(unsafe { x.unwrap_err_unchecked() }, \"emergency failure\");
\n
",0,"clap::error::Result"],["
source§

impl<T, E> Result<&T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"clap::error::Result"],["
source§

impl<T, E> Result<&mut T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&mut T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&mut T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"clap::error::Result"],["
source§

impl<T, E> Result<Option<T>, E>

1.33.0 (const: unstable) · source

pub fn transpose(self) -> Option<Result<T, E>>

Transposes a Result of an Option into an Option of a Result.

\n

Ok(None) will be mapped to None.\nOk(Some(_)) and Err(_) will be mapped to Some(Ok(_)) and Some(Err(_)).

\n
Examples
\n
#[derive(Debug, Eq, PartialEq)]\nstruct SomeErr;\n\nlet x: Result<Option<i32>, SomeErr> = Ok(Some(5));\nlet y: Option<Result<i32, SomeErr>> = Some(Ok(5));\nassert_eq!(x.transpose(), y);
\n
",0,"clap::error::Result"],["
source§

impl<T, E> Result<Result<T, E>, E>

source

pub fn flatten(self) -> Result<T, E>

🔬This is a nightly-only experimental API. (result_flattening)

Converts from Result<Result<T, E>, E> to Result<T, E>

\n
Examples
\n
#![feature(result_flattening)]\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Ok(\"hello\"));\nassert_eq!(Ok(\"hello\"), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Err(6));\nassert_eq!(Err(6), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Err(6);\nassert_eq!(Err(6), x.flatten());
\n

Flattening only removes one level of nesting at a time:

\n\n
#![feature(result_flattening)]\nlet x: Result<Result<Result<&'static str, u32>, u32>, u32> = Ok(Ok(Ok(\"hello\")));\nassert_eq!(Ok(Ok(\"hello\")), x.flatten());\nassert_eq!(Ok(\"hello\"), x.flatten().flatten());
\n
",0,"clap::error::Result"],["
1.61.0 · source§

impl<T, E> Termination for Result<T, E>
where\n T: Termination,\n E: Debug,

source§

fn report(self) -> ExitCode

Is called to get the representation of the value as status code.\nThis status code is returned to the operating system.
","Termination","clap::error::Result"],["
source§

impl<T, E> Try for Result<T, E>

§

type Output = T

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value produced by ? when not short-circuiting.
§

type Residual = Result<Infallible, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value passed to FromResidual::from_residual\nas part of ? when short-circuiting. Read more
source§

fn from_output(output: <Result<T, E> as Try>::Output) -> Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from its Output type. Read more
source§

fn branch(\n self\n) -> ControlFlow<<Result<T, E> as Try>::Residual, <Result<T, E> as Try>::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)
Used in ? to decide whether the operator should produce a value\n(because this returned ControlFlow::Continue)\nor propagate a value back to the caller\n(because this returned ControlFlow::Break). Read more
","Try","clap::error::Result"],["
1.16.0 · source§

impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
where\n T: Sum<U>,

source§

fn sum<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the sum of all elements is returned.

\n
Examples
\n

This sums up every integer in a vector, rejecting the sum if a negative\nelement is encountered:

\n\n
let f = |&x: &i32| if x < 0 { Err(\"Negative element found\") } else { Ok(x) };\nlet v = vec![1, 2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Ok(3));\nlet v = vec![1, -2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Err(\"Negative element found\"));
\n
","Sum>","clap::error::Result"],["
1.0.0 · source§

impl<T, E> Debug for Result<T, E>
where\n T: Debug,\n E: Debug,

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
","Debug","clap::error::Result"],["
1.0.0 · source§

impl<T, E> Clone for Result<T, E>
where\n T: Clone,\n E: Clone,

source§

fn clone(&self) -> Result<T, E>

Returns a copy of the value. Read more
source§

fn clone_from(&mut self, source: &Result<T, E>)

Performs copy-assignment from source. Read more
","Clone","clap::error::Result"],["
1.0.0 · source§

impl<T, E> StructuralEq for Result<T, E>

","StructuralEq","clap::error::Result"],["
1.16.0 · source§

impl<T, U, E> Product<Result<U, E>> for Result<T, E>
where\n T: Product<U>,

source§

fn product<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the product of all elements is returned.

\n
Examples
\n

This multiplies each number in a vector of strings,\nif a string could not be parsed the operation returns Err:

\n\n
let nums = vec![\"5\", \"10\", \"1\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert_eq!(total, Ok(100));\nlet nums = vec![\"5\", \"10\", \"one\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert!(total.is_err());
\n
","Product>","clap::error::Result"],["
1.0.0 · source§

impl<T, E> Eq for Result<T, E>
where\n T: Eq,\n E: Eq,

","Eq","clap::error::Result"],["
1.0.0 · source§

impl<T, E> Ord for Result<T, E>
where\n T: Ord,\n E: Ord,

source§

fn cmp(&self, other: &Result<T, E>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Self
where\n Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
","Ord","clap::error::Result"],["
source§

impl<T, E> Residual<T> for Result<Infallible, E>

§

type TryType = Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2_residual)
The “return” type of this meta-function.
","Residual","clap::error::Result"],["
1.0.0 · source§

impl<T, E> PartialEq for Result<T, E>
where\n T: PartialEq,\n E: PartialEq,

source§

fn eq(&self, other: &Result<T, E>) -> bool

This method tests for self and other values to be equal, and is used\nby ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always\nsufficient, and should not be overridden without very good reason.
","PartialEq","clap::error::Result"],["
1.0.0 · source§

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>
where\n V: FromIterator<A>,

source§

fn from_iter<I>(iter: I) -> Result<V, E>
where\n I: IntoIterator<Item = Result<A, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err occur, a\ncontainer with the values of each Result is returned.

\n

Here is an example which increments every integer in a vector,\nchecking for overflow:

\n\n
let v = vec![1, 2];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_add(1).ok_or(\"Overflow!\")\n).collect();\nassert_eq!(res, Ok(vec![2, 3]));
\n

Here is another example that tries to subtract one from another list\nof integers, this time checking for underflow:

\n\n
let v = vec![1, 2, 0];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_sub(1).ok_or(\"Underflow!\")\n).collect();\nassert_eq!(res, Err(\"Underflow!\"));
\n

Here is a variation on the previous example, showing that no\nfurther elements are taken from iter after the first Err.

\n\n
let v = vec![3, 2, 1, 10];\nlet mut shared = 0;\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32| {\n    shared += x;\n    x.checked_sub(2).ok_or(\"Underflow!\")\n}).collect();\nassert_eq!(res, Err(\"Underflow!\"));\nassert_eq!(shared, 6);
\n

Since the third element caused an underflow, no further elements were taken,\nso the final value of shared is 6 (= 3 + 2 + 1), not 16.

\n
","FromIterator>","clap::error::Result"],["
1.0.0 · source§

impl<T, E> StructuralPartialEq for Result<T, E>

","StructuralPartialEq","clap::error::Result"],["
1.0.0 · source§

impl<T, E> Copy for Result<T, E>
where\n T: Copy,\n E: Copy,

","Copy","clap::error::Result"],["
1.0.0 · source§

impl<T, E> Hash for Result<T, E>
where\n T: Hash,\n E: Hash,

source§

fn hash<__H>(&self, state: &mut __H)
where\n __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)
where\n H: Hasher,\n Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
","Hash","clap::error::Result"],["
1.0.0 · source§

impl<T, E> IntoIterator for Result<T, E>

source§

fn into_iter(self) -> IntoIter<T>

Returns a consuming iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(5);\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, [5]);\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, []);
\n
§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
","IntoIterator","clap::error::Result"],["
1.0.0 · source§

impl<T, E> PartialOrd for Result<T, E>
where\n T: PartialOrd,\n E: PartialOrd,

source§

fn partial_cmp(&self, other: &Result<T, E>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <=\noperator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >=\noperator. Read more
","PartialOrd","clap::error::Result"],["
source§

impl<T, E, F> FromResidual<Yeet<E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(_: Yeet<E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","clap::error::Result"],["
source§

impl<T, E, F> FromResidual<Result<Infallible, E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(residual: Result<Infallible, E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","clap::error::Result"],["
source§

impl From<StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From","clap::error::Result"],["
source§

impl From<&StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: &StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From<&StreamResult>","clap::error::Result"]], -"clap_builder":[["
source§

impl<T, E> Result<T, E>

1.0.0 (const: 1.48.0) · source

pub const fn is_ok(&self) -> bool

Returns true if the result is Ok.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_ok(), true);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_ok(), false);
\n
1.70.0 · source

pub fn is_ok_and(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the result is Ok and the value inside of it matches a predicate.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.is_ok_and(|x| x > 1), true);\n\nlet x: Result<u32, &str> = Ok(0);\nassert_eq!(x.is_ok_and(|x| x > 1), false);\n\nlet x: Result<u32, &str> = Err(\"hey\");\nassert_eq!(x.is_ok_and(|x| x > 1), false);
\n
1.0.0 (const: 1.48.0) · source

pub const fn is_err(&self) -> bool

Returns true if the result is Err.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_err(), false);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_err(), true);
\n
1.70.0 · source

pub fn is_err_and(self, f: impl FnOnce(E) -> bool) -> bool

Returns true if the result is Err and the value inside of it matches a predicate.

\n
Examples
\n
use std::io::{Error, ErrorKind};\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), true);\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);\n\nlet x: Result<u32, Error> = Ok(123);\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);
\n
1.0.0 · source

pub fn ok(self) -> Option<T>

Converts from Result<T, E> to Option<T>.

\n

Converts self into an Option<T>, consuming self,\nand discarding the error, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.ok(), Some(2));\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.ok(), None);
\n
1.0.0 · source

pub fn err(self) -> Option<E>

Converts from Result<T, E> to Option<E>.

\n

Converts self into an Option<E>, consuming self,\nand discarding the success value, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.err(), None);\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.err(), Some(\"Nothing here\"));
\n
1.0.0 (const: 1.48.0) · source

pub const fn as_ref(&self) -> Result<&T, &E>

Converts from &Result<T, E> to Result<&T, &E>.

\n

Produces a new Result, containing a reference\ninto the original, leaving the original in place.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.as_ref(), Ok(&2));\n\nlet x: Result<u32, &str> = Err(\"Error\");\nassert_eq!(x.as_ref(), Err(&\"Error\"));
\n
1.0.0 (const: unstable) · source

pub fn as_mut(&mut self) -> Result<&mut T, &mut E>

Converts from &mut Result<T, E> to Result<&mut T, &mut E>.

\n
Examples
\n
fn mutate(r: &mut Result<i32, i32>) {\n    match r.as_mut() {\n        Ok(v) => *v = 42,\n        Err(e) => *e = 0,\n    }\n}\n\nlet mut x: Result<i32, i32> = Ok(2);\nmutate(&mut x);\nassert_eq!(x.unwrap(), 42);\n\nlet mut x: Result<i32, i32> = Err(13);\nmutate(&mut x);\nassert_eq!(x.unwrap_err(), 0);
\n
1.0.0 · source

pub fn map<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> U,

Maps a Result<T, E> to Result<U, E> by applying a function to a\ncontained Ok value, leaving an Err value untouched.

\n

This function can be used to compose the results of two functions.

\n
Examples
\n

Print the numbers on each line of a string multiplied by two.

\n\n
let line = \"1\\n2\\n3\\n4\\n\";\n\nfor num in line.lines() {\n    match num.parse::<i32>().map(|i| i * 2) {\n        Ok(n) => println!(\"{n}\"),\n        Err(..) => {}\n    }\n}
\n
1.41.0 · source

pub fn map_or<U, F>(self, default: U, f: F) -> U
where\n F: FnOnce(T) -> U,

Returns the provided default (if Err), or\napplies a function to the contained value (if Ok).

\n

Arguments passed to map_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use map_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let x: Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or(42, |v| v.len()), 3);\n\nlet x: Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or(42, |v| v.len()), 42);
\n
1.41.0 · source

pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
where\n D: FnOnce(E) -> U,\n F: FnOnce(T) -> U,

Maps a Result<T, E> to U by applying fallback function default to\na contained Err value, or function f to a contained Ok value.

\n

This function can be used to unpack a successful result\nwhile handling an error.

\n
Examples
\n
let k = 21;\n\nlet x : Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 3);\n\nlet x : Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 42);
\n
1.0.0 · source

pub fn map_err<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> F,

Maps a Result<T, E> to Result<T, F> by applying a function to a\ncontained Err value, leaving an Ok value untouched.

\n

This function can be used to pass through a successful result while handling\nan error.

\n
Examples
\n
fn stringify(x: u32) -> String { format!(\"error code: {x}\") }\n\nlet x: Result<u32, u32> = Ok(2);\nassert_eq!(x.map_err(stringify), Ok(2));\n\nlet x: Result<u32, u32> = Err(13);\nassert_eq!(x.map_err(stringify), Err(\"error code: 13\".to_string()));
\n
1.76.0 · source

pub fn inspect<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&T),

Calls the provided closure with a reference to the contained value (if Ok).

\n
Examples
\n
let x: u8 = \"4\"\n    .parse::<u8>()\n    .inspect(|x| println!(\"original: {x}\"))\n    .map(|x| x.pow(3))\n    .expect(\"failed to parse number\");
\n
1.76.0 · source

pub fn inspect_err<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&E),

Calls the provided closure with a reference to the contained error (if Err).

\n
Examples
\n
use std::{fs, io};\n\nfn read() -> io::Result<String> {\n    fs::read_to_string(\"address.txt\")\n        .inspect_err(|e| eprintln!(\"failed to read file: {e}\"))\n}
\n
1.47.0 · source

pub fn as_deref(&self) -> Result<&<T as Deref>::Target, &E>
where\n T: Deref,

Converts from Result<T, E> (or &Result<T, E>) to Result<&<T as Deref>::Target, &E>.

\n

Coerces the Ok variant of the original Result via Deref\nand returns the new Result.

\n
Examples
\n
let x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&str, &u32> = Ok(\"hello\");\nassert_eq!(x.as_deref(), y);\n\nlet x: Result<String, u32> = Err(42);\nlet y: Result<&str, &u32> = Err(&42);\nassert_eq!(x.as_deref(), y);
\n
1.47.0 · source

pub fn as_deref_mut(&mut self) -> Result<&mut <T as Deref>::Target, &mut E>
where\n T: DerefMut,

Converts from Result<T, E> (or &mut Result<T, E>) to Result<&mut <T as DerefMut>::Target, &mut E>.

\n

Coerces the Ok variant of the original Result via DerefMut\nand returns the new Result.

\n
Examples
\n
let mut s = \"HELLO\".to_string();\nlet mut x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&mut str, &mut u32> = Ok(&mut s);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);\n\nlet mut i = 42;\nlet mut x: Result<String, u32> = Err(42);\nlet y: Result<&mut str, &mut u32> = Err(&mut i);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
\n
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(7);\nassert_eq!(x.iter().next(), Some(&7));\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter().next(), None);
\n
1.0.0 · source

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns a mutable iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let mut x: Result<u32, &str> = Ok(7);\nmatch x.iter_mut().next() {\n    Some(v) => *v = 40,\n    None => {},\n}\nassert_eq!(x, Ok(40));\n\nlet mut x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter_mut().next(), None);
\n
1.4.0 · source

pub fn expect(self, msg: &str) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message including the\npassed message, and the content of the Err.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.expect(\"Testing expect\"); // panics with `Testing expect: emergency failure`
\n
Recommended Message Style
\n

We recommend that expect messages are used to describe the reason you\nexpect the Result should be Ok.

\n\n
ⓘ
let path = std::env::var(\"IMPORTANT_PATH\")\n    .expect(\"env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`\");
\n

Hint: If you’re having trouble remembering how to phrase expect\nerror messages remember to focus on the word “should” as in “env\nvariable should be set by blah” or “the given binary should be available\nand executable by the current user”.

\n

For more detail on expect message styles and the reasoning behind our recommendation please\nrefer to the section on “Common Message\nStyles” in the\nstd::error module docs.

\n
1.0.0 · source

pub fn unwrap(self) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message provided by the\nErr’s value.

\n
Examples
\n

Basic usage:

\n\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.unwrap(), 2);
\n\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.unwrap(); // panics with `emergency failure`
\n
1.16.0 · source

pub fn unwrap_or_default(self) -> T
where\n T: Default,

Returns the contained Ok value or a default

\n

Consumes the self argument then, if Ok, returns the contained\nvalue, otherwise if Err, returns the default value for that\ntype.

\n
Examples
\n

Converts a string to an integer, turning poorly-formed strings\ninto 0 (the default value for integers). parse converts\na string to any other type that implements FromStr, returning an\nErr on error.

\n\n
let good_year_from_input = \"1909\";\nlet bad_year_from_input = \"190blarg\";\nlet good_year = good_year_from_input.parse().unwrap_or_default();\nlet bad_year = bad_year_from_input.parse().unwrap_or_default();\n\nassert_eq!(1909, good_year);\nassert_eq!(0, bad_year);
\n
1.17.0 · source

pub fn expect_err(self, msg: &str) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a panic message including the\npassed message, and the content of the Ok.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(10);\nx.expect_err(\"Testing expect_err\"); // panics with `Testing expect_err: 10`
\n
1.0.0 · source

pub fn unwrap_err(self) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a custom panic message provided\nby the Ok’s value.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(2);\nx.unwrap_err(); // panics with `2`
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(x.unwrap_err(), \"emergency failure\");
\n
source

pub fn into_ok(self) -> T
where\n E: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Ok value, but never panics.

\n

Unlike unwrap, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap as a maintainability safeguard that will fail\nto compile if the error type of the Result is later changed\nto an error that can actually occur.

\n
Examples
\n
\nfn only_good_news() -> Result<String, !> {\n    Ok(\"this is fine\".into())\n}\n\nlet s: String = only_good_news().into_ok();\nprintln!(\"{s}\");
\n
source

pub fn into_err(self) -> E
where\n T: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Err value, but never panics.

\n

Unlike unwrap_err, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap_err as a maintainability safeguard that will fail\nto compile if the ok type of the Result is later changed\nto a type that can actually occur.

\n
Examples
\n
\nfn only_bad_news() -> Result<!, String> {\n    Err(\"Oops, it failed\".into())\n}\n\nlet error: String = only_bad_news().into_err();\nprintln!(\"{error}\");
\n
1.0.0 · source

pub fn and<U>(self, res: Result<U, E>) -> Result<U, E>

Returns res if the result is Ok, otherwise returns the Err value of self.

\n

Arguments passed to and are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use and_then, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<&str, &str> = Ok(\"foo\");\nassert_eq!(x.and(y), Err(\"early error\"));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"not a 2\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Ok(\"different result type\");\nassert_eq!(x.and(y), Ok(\"different result type\"));
\n
1.0.0 · source

pub fn and_then<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> Result<U, E>,

Calls op if the result is Ok, otherwise returns the Err value of self.

\n

This function can be used for control flow based on Result values.

\n
Examples
\n
fn sq_then_to_string(x: u32) -> Result<String, &'static str> {\n    x.checked_mul(x).map(|sq| sq.to_string()).ok_or(\"overflowed\")\n}\n\nassert_eq!(Ok(2).and_then(sq_then_to_string), Ok(4.to_string()));\nassert_eq!(Ok(1_000_000).and_then(sq_then_to_string), Err(\"overflowed\"));\nassert_eq!(Err(\"not a number\").and_then(sq_then_to_string), Err(\"not a number\"));
\n

Often used to chain fallible operations that may return Err.

\n\n
use std::{io::ErrorKind, path::Path};\n\n// Note: on Windows \"/\" maps to \"C:\\\"\nlet root_modified_time = Path::new(\"/\").metadata().and_then(|md| md.modified());\nassert!(root_modified_time.is_ok());\n\nlet should_fail = Path::new(\"/bad/path\").metadata().and_then(|md| md.modified());\nassert!(should_fail.is_err());\nassert_eq!(should_fail.unwrap_err().kind(), ErrorKind::NotFound);
\n
1.0.0 · source

pub fn or<F>(self, res: Result<T, F>) -> Result<T, F>

Returns res if the result is Err, otherwise returns the Ok value of self.

\n

Arguments passed to or are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use or_else, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<u32, &str> = Ok(2);\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Ok(100);\nassert_eq!(x.or(y), Ok(2));
\n
1.0.0 · source

pub fn or_else<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> Result<T, F>,

Calls op if the result is Err, otherwise returns the Ok value of self.

\n

This function can be used for control flow based on result values.

\n
Examples
\n
fn sq(x: u32) -> Result<u32, u32> { Ok(x * x) }\nfn err(x: u32) -> Result<u32, u32> { Err(x) }\n\nassert_eq!(Ok(2).or_else(sq).or_else(sq), Ok(2));\nassert_eq!(Ok(2).or_else(err).or_else(sq), Ok(2));\nassert_eq!(Err(3).or_else(sq).or_else(err), Ok(9));\nassert_eq!(Err(3).or_else(err).or_else(err), Err(3));
\n
1.0.0 · source

pub fn unwrap_or(self, default: T) -> T

Returns the contained Ok value or a provided default.

\n

Arguments passed to unwrap_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use unwrap_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let default = 2;\nlet x: Result<u32, &str> = Ok(9);\nassert_eq!(x.unwrap_or(default), 9);\n\nlet x: Result<u32, &str> = Err(\"error\");\nassert_eq!(x.unwrap_or(default), default);
\n
1.0.0 · source

pub fn unwrap_or_else<F>(self, op: F) -> T
where\n F: FnOnce(E) -> T,

Returns the contained Ok value or computes it from a closure.

\n
Examples
\n
fn count(x: &str) -> usize { x.len() }\n\nassert_eq!(Ok(2).unwrap_or_else(count), 2);\nassert_eq!(Err(\"foo\").unwrap_or_else(count), 3);
\n
1.58.0 · source

pub unsafe fn unwrap_unchecked(self) -> T

Returns the contained Ok value, consuming the self value,\nwithout checking that the value is not an Err.

\n
Safety
\n

Calling this method on an Err is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(unsafe { x.unwrap_unchecked() }, 2);
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nunsafe { x.unwrap_unchecked(); } // Undefined behavior!
\n
1.58.0 · source

pub unsafe fn unwrap_err_unchecked(self) -> E

Returns the contained Err value, consuming the self value,\nwithout checking that the value is not an Ok.

\n
Safety
\n

Calling this method on an Ok is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nunsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(unsafe { x.unwrap_err_unchecked() }, \"emergency failure\");
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<&T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<&mut T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&mut T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&mut T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<Option<T>, E>

1.33.0 (const: unstable) · source

pub fn transpose(self) -> Option<Result<T, E>>

Transposes a Result of an Option into an Option of a Result.

\n

Ok(None) will be mapped to None.\nOk(Some(_)) and Err(_) will be mapped to Some(Ok(_)) and Some(Err(_)).

\n
Examples
\n
#[derive(Debug, Eq, PartialEq)]\nstruct SomeErr;\n\nlet x: Result<Option<i32>, SomeErr> = Ok(Some(5));\nlet y: Option<Result<i32, SomeErr>> = Some(Ok(5));\nassert_eq!(x.transpose(), y);
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<Result<T, E>, E>

source

pub fn flatten(self) -> Result<T, E>

🔬This is a nightly-only experimental API. (result_flattening)

Converts from Result<Result<T, E>, E> to Result<T, E>

\n
Examples
\n
#![feature(result_flattening)]\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Ok(\"hello\"));\nassert_eq!(Ok(\"hello\"), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Err(6));\nassert_eq!(Err(6), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Err(6);\nassert_eq!(Err(6), x.flatten());
\n

Flattening only removes one level of nesting at a time:

\n\n
#![feature(result_flattening)]\nlet x: Result<Result<Result<&'static str, u32>, u32>, u32> = Ok(Ok(Ok(\"hello\")));\nassert_eq!(Ok(Ok(\"hello\")), x.flatten());\nassert_eq!(Ok(\"hello\"), x.flatten().flatten());
\n
",0,"clap_builder::error::Result"],["
1.61.0 · source§

impl<T, E> Termination for Result<T, E>
where\n T: Termination,\n E: Debug,

source§

fn report(self) -> ExitCode

Is called to get the representation of the value as status code.\nThis status code is returned to the operating system.
","Termination","clap_builder::error::Result"],["
source§

impl<T, E> Try for Result<T, E>

§

type Output = T

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value produced by ? when not short-circuiting.
§

type Residual = Result<Infallible, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value passed to FromResidual::from_residual\nas part of ? when short-circuiting. Read more
source§

fn from_output(output: <Result<T, E> as Try>::Output) -> Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from its Output type. Read more
source§

fn branch(\n self\n) -> ControlFlow<<Result<T, E> as Try>::Residual, <Result<T, E> as Try>::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)
Used in ? to decide whether the operator should produce a value\n(because this returned ControlFlow::Continue)\nor propagate a value back to the caller\n(because this returned ControlFlow::Break). Read more
","Try","clap_builder::error::Result"],["
1.16.0 · source§

impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
where\n T: Sum<U>,

source§

fn sum<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the sum of all elements is returned.

\n
Examples
\n

This sums up every integer in a vector, rejecting the sum if a negative\nelement is encountered:

\n\n
let f = |&x: &i32| if x < 0 { Err(\"Negative element found\") } else { Ok(x) };\nlet v = vec![1, 2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Ok(3));\nlet v = vec![1, -2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Err(\"Negative element found\"));
\n
","Sum>","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Debug for Result<T, E>
where\n T: Debug,\n E: Debug,

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
","Debug","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Clone for Result<T, E>
where\n T: Clone,\n E: Clone,

source§

fn clone(&self) -> Result<T, E>

Returns a copy of the value. Read more
source§

fn clone_from(&mut self, source: &Result<T, E>)

Performs copy-assignment from source. Read more
","Clone","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> StructuralEq for Result<T, E>

","StructuralEq","clap_builder::error::Result"],["
1.16.0 · source§

impl<T, U, E> Product<Result<U, E>> for Result<T, E>
where\n T: Product<U>,

source§

fn product<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the product of all elements is returned.

\n
Examples
\n

This multiplies each number in a vector of strings,\nif a string could not be parsed the operation returns Err:

\n\n
let nums = vec![\"5\", \"10\", \"1\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert_eq!(total, Ok(100));\nlet nums = vec![\"5\", \"10\", \"one\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert!(total.is_err());
\n
","Product>","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Eq for Result<T, E>
where\n T: Eq,\n E: Eq,

","Eq","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Ord for Result<T, E>
where\n T: Ord,\n E: Ord,

source§

fn cmp(&self, other: &Result<T, E>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Self
where\n Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
","Ord","clap_builder::error::Result"],["
source§

impl<T, E> Residual<T> for Result<Infallible, E>

§

type TryType = Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2_residual)
The “return” type of this meta-function.
","Residual","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> PartialEq for Result<T, E>
where\n T: PartialEq,\n E: PartialEq,

source§

fn eq(&self, other: &Result<T, E>) -> bool

This method tests for self and other values to be equal, and is used\nby ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always\nsufficient, and should not be overridden without very good reason.
","PartialEq","clap_builder::error::Result"],["
1.0.0 · source§

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>
where\n V: FromIterator<A>,

source§

fn from_iter<I>(iter: I) -> Result<V, E>
where\n I: IntoIterator<Item = Result<A, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err occur, a\ncontainer with the values of each Result is returned.

\n

Here is an example which increments every integer in a vector,\nchecking for overflow:

\n\n
let v = vec![1, 2];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_add(1).ok_or(\"Overflow!\")\n).collect();\nassert_eq!(res, Ok(vec![2, 3]));
\n

Here is another example that tries to subtract one from another list\nof integers, this time checking for underflow:

\n\n
let v = vec![1, 2, 0];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_sub(1).ok_or(\"Underflow!\")\n).collect();\nassert_eq!(res, Err(\"Underflow!\"));
\n

Here is a variation on the previous example, showing that no\nfurther elements are taken from iter after the first Err.

\n\n
let v = vec![3, 2, 1, 10];\nlet mut shared = 0;\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32| {\n    shared += x;\n    x.checked_sub(2).ok_or(\"Underflow!\")\n}).collect();\nassert_eq!(res, Err(\"Underflow!\"));\nassert_eq!(shared, 6);
\n

Since the third element caused an underflow, no further elements were taken,\nso the final value of shared is 6 (= 3 + 2 + 1), not 16.

\n
","FromIterator>","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> StructuralPartialEq for Result<T, E>

","StructuralPartialEq","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Copy for Result<T, E>
where\n T: Copy,\n E: Copy,

","Copy","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Hash for Result<T, E>
where\n T: Hash,\n E: Hash,

source§

fn hash<__H>(&self, state: &mut __H)
where\n __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)
where\n H: Hasher,\n Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
","Hash","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> IntoIterator for Result<T, E>

source§

fn into_iter(self) -> IntoIter<T>

Returns a consuming iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(5);\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, [5]);\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, []);
\n
§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
","IntoIterator","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> PartialOrd for Result<T, E>
where\n T: PartialOrd,\n E: PartialOrd,

source§

fn partial_cmp(&self, other: &Result<T, E>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <=\noperator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >=\noperator. Read more
","PartialOrd","clap_builder::error::Result"],["
source§

impl<T, E, F> FromResidual<Yeet<E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(_: Yeet<E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","clap_builder::error::Result"],["
source§

impl<T, E, F> FromResidual<Result<Infallible, E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(residual: Result<Infallible, E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","clap_builder::error::Result"],["
source§

impl From<StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From","clap_builder::error::Result"],["
source§

impl From<&StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: &StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From<&StreamResult>","clap_builder::error::Result"]], +"clap_builder":[["
source§

impl<T, E> Result<T, E>

1.0.0 (const: 1.48.0) · source

pub const fn is_ok(&self) -> bool

Returns true if the result is Ok.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_ok(), true);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_ok(), false);
\n
1.70.0 · source

pub fn is_ok_and(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the result is Ok and the value inside of it matches a predicate.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.is_ok_and(|x| x > 1), true);\n\nlet x: Result<u32, &str> = Ok(0);\nassert_eq!(x.is_ok_and(|x| x > 1), false);\n\nlet x: Result<u32, &str> = Err(\"hey\");\nassert_eq!(x.is_ok_and(|x| x > 1), false);
\n
1.0.0 (const: 1.48.0) · source

pub const fn is_err(&self) -> bool

Returns true if the result is Err.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_err(), false);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_err(), true);
\n
1.70.0 · source

pub fn is_err_and(self, f: impl FnOnce(E) -> bool) -> bool

Returns true if the result is Err and the value inside of it matches a predicate.

\n
Examples
\n
use std::io::{Error, ErrorKind};\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), true);\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);\n\nlet x: Result<u32, Error> = Ok(123);\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);
\n
1.0.0 · source

pub fn ok(self) -> Option<T>

Converts from Result<T, E> to Option<T>.

\n

Converts self into an Option<T>, consuming self,\nand discarding the error, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.ok(), Some(2));\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.ok(), None);
\n
1.0.0 · source

pub fn err(self) -> Option<E>

Converts from Result<T, E> to Option<E>.

\n

Converts self into an Option<E>, consuming self,\nand discarding the success value, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.err(), None);\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.err(), Some(\"Nothing here\"));
\n
1.0.0 (const: 1.48.0) · source

pub const fn as_ref(&self) -> Result<&T, &E>

Converts from &Result<T, E> to Result<&T, &E>.

\n

Produces a new Result, containing a reference\ninto the original, leaving the original in place.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.as_ref(), Ok(&2));\n\nlet x: Result<u32, &str> = Err(\"Error\");\nassert_eq!(x.as_ref(), Err(&\"Error\"));
\n
1.0.0 (const: unstable) · source

pub fn as_mut(&mut self) -> Result<&mut T, &mut E>

Converts from &mut Result<T, E> to Result<&mut T, &mut E>.

\n
Examples
\n
fn mutate(r: &mut Result<i32, i32>) {\n    match r.as_mut() {\n        Ok(v) => *v = 42,\n        Err(e) => *e = 0,\n    }\n}\n\nlet mut x: Result<i32, i32> = Ok(2);\nmutate(&mut x);\nassert_eq!(x.unwrap(), 42);\n\nlet mut x: Result<i32, i32> = Err(13);\nmutate(&mut x);\nassert_eq!(x.unwrap_err(), 0);
\n
1.0.0 · source

pub fn map<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> U,

Maps a Result<T, E> to Result<U, E> by applying a function to a\ncontained Ok value, leaving an Err value untouched.

\n

This function can be used to compose the results of two functions.

\n
Examples
\n

Print the numbers on each line of a string multiplied by two.

\n\n
let line = \"1\\n2\\n3\\n4\\n\";\n\nfor num in line.lines() {\n    match num.parse::<i32>().map(|i| i * 2) {\n        Ok(n) => println!(\"{n}\"),\n        Err(..) => {}\n    }\n}
\n
1.41.0 · source

pub fn map_or<U, F>(self, default: U, f: F) -> U
where\n F: FnOnce(T) -> U,

Returns the provided default (if Err), or\napplies a function to the contained value (if Ok).

\n

Arguments passed to map_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use map_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let x: Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or(42, |v| v.len()), 3);\n\nlet x: Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or(42, |v| v.len()), 42);
\n
1.41.0 · source

pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
where\n D: FnOnce(E) -> U,\n F: FnOnce(T) -> U,

Maps a Result<T, E> to U by applying fallback function default to\na contained Err value, or function f to a contained Ok value.

\n

This function can be used to unpack a successful result\nwhile handling an error.

\n
Examples
\n
let k = 21;\n\nlet x : Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 3);\n\nlet x : Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 42);
\n
1.0.0 · source

pub fn map_err<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> F,

Maps a Result<T, E> to Result<T, F> by applying a function to a\ncontained Err value, leaving an Ok value untouched.

\n

This function can be used to pass through a successful result while handling\nan error.

\n
Examples
\n
fn stringify(x: u32) -> String { format!(\"error code: {x}\") }\n\nlet x: Result<u32, u32> = Ok(2);\nassert_eq!(x.map_err(stringify), Ok(2));\n\nlet x: Result<u32, u32> = Err(13);\nassert_eq!(x.map_err(stringify), Err(\"error code: 13\".to_string()));
\n
1.76.0 · source

pub fn inspect<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&T),

Calls the provided closure with a reference to the contained value (if Ok).

\n
Examples
\n
let x: u8 = \"4\"\n    .parse::<u8>()\n    .inspect(|x| println!(\"original: {x}\"))\n    .map(|x| x.pow(3))\n    .expect(\"failed to parse number\");
\n
1.76.0 · source

pub fn inspect_err<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&E),

Calls the provided closure with a reference to the contained error (if Err).

\n
Examples
\n
use std::{fs, io};\n\nfn read() -> io::Result<String> {\n    fs::read_to_string(\"address.txt\")\n        .inspect_err(|e| eprintln!(\"failed to read file: {e}\"))\n}
\n
1.47.0 · source

pub fn as_deref(&self) -> Result<&<T as Deref>::Target, &E>
where\n T: Deref,

Converts from Result<T, E> (or &Result<T, E>) to Result<&<T as Deref>::Target, &E>.

\n

Coerces the Ok variant of the original Result via Deref\nand returns the new Result.

\n
Examples
\n
let x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&str, &u32> = Ok(\"hello\");\nassert_eq!(x.as_deref(), y);\n\nlet x: Result<String, u32> = Err(42);\nlet y: Result<&str, &u32> = Err(&42);\nassert_eq!(x.as_deref(), y);
\n
1.47.0 · source

pub fn as_deref_mut(&mut self) -> Result<&mut <T as Deref>::Target, &mut E>
where\n T: DerefMut,

Converts from Result<T, E> (or &mut Result<T, E>) to Result<&mut <T as DerefMut>::Target, &mut E>.

\n

Coerces the Ok variant of the original Result via DerefMut\nand returns the new Result.

\n
Examples
\n
let mut s = \"HELLO\".to_string();\nlet mut x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&mut str, &mut u32> = Ok(&mut s);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);\n\nlet mut i = 42;\nlet mut x: Result<String, u32> = Err(42);\nlet y: Result<&mut str, &mut u32> = Err(&mut i);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
\n
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(7);\nassert_eq!(x.iter().next(), Some(&7));\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter().next(), None);
\n
1.0.0 · source

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns a mutable iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let mut x: Result<u32, &str> = Ok(7);\nmatch x.iter_mut().next() {\n    Some(v) => *v = 40,\n    None => {},\n}\nassert_eq!(x, Ok(40));\n\nlet mut x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter_mut().next(), None);
\n
1.4.0 · source

pub fn expect(self, msg: &str) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message including the\npassed message, and the content of the Err.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.expect(\"Testing expect\"); // panics with `Testing expect: emergency failure`
\n
Recommended Message Style
\n

We recommend that expect messages are used to describe the reason you\nexpect the Result should be Ok.

\n\n
ⓘ
let path = std::env::var(\"IMPORTANT_PATH\")\n    .expect(\"env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`\");
\n

Hint: If you’re having trouble remembering how to phrase expect\nerror messages remember to focus on the word “should” as in “env\nvariable should be set by blah” or “the given binary should be available\nand executable by the current user”.

\n

For more detail on expect message styles and the reasoning behind our recommendation please\nrefer to the section on “Common Message\nStyles” in the\nstd::error module docs.

\n
1.0.0 · source

pub fn unwrap(self) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message provided by the\nErr’s value.

\n
Examples
\n

Basic usage:

\n\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.unwrap(), 2);
\n\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.unwrap(); // panics with `emergency failure`
\n
1.16.0 · source

pub fn unwrap_or_default(self) -> T
where\n T: Default,

Returns the contained Ok value or a default

\n

Consumes the self argument then, if Ok, returns the contained\nvalue, otherwise if Err, returns the default value for that\ntype.

\n
Examples
\n

Converts a string to an integer, turning poorly-formed strings\ninto 0 (the default value for integers). parse converts\na string to any other type that implements FromStr, returning an\nErr on error.

\n\n
let good_year_from_input = \"1909\";\nlet bad_year_from_input = \"190blarg\";\nlet good_year = good_year_from_input.parse().unwrap_or_default();\nlet bad_year = bad_year_from_input.parse().unwrap_or_default();\n\nassert_eq!(1909, good_year);\nassert_eq!(0, bad_year);
\n
1.17.0 · source

pub fn expect_err(self, msg: &str) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a panic message including the\npassed message, and the content of the Ok.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(10);\nx.expect_err(\"Testing expect_err\"); // panics with `Testing expect_err: 10`
\n
1.0.0 · source

pub fn unwrap_err(self) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a custom panic message provided\nby the Ok’s value.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(2);\nx.unwrap_err(); // panics with `2`
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(x.unwrap_err(), \"emergency failure\");
\n
source

pub fn into_ok(self) -> T
where\n E: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Ok value, but never panics.

\n

Unlike unwrap, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap as a maintainability safeguard that will fail\nto compile if the error type of the Result is later changed\nto an error that can actually occur.

\n
Examples
\n
\nfn only_good_news() -> Result<String, !> {\n    Ok(\"this is fine\".into())\n}\n\nlet s: String = only_good_news().into_ok();\nprintln!(\"{s}\");
\n
source

pub fn into_err(self) -> E
where\n T: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Err value, but never panics.

\n

Unlike unwrap_err, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap_err as a maintainability safeguard that will fail\nto compile if the ok type of the Result is later changed\nto a type that can actually occur.

\n
Examples
\n
\nfn only_bad_news() -> Result<!, String> {\n    Err(\"Oops, it failed\".into())\n}\n\nlet error: String = only_bad_news().into_err();\nprintln!(\"{error}\");
\n
1.0.0 · source

pub fn and<U>(self, res: Result<U, E>) -> Result<U, E>

Returns res if the result is Ok, otherwise returns the Err value of self.

\n

Arguments passed to and are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use and_then, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<&str, &str> = Ok(\"foo\");\nassert_eq!(x.and(y), Err(\"early error\"));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"not a 2\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Ok(\"different result type\");\nassert_eq!(x.and(y), Ok(\"different result type\"));
\n
1.0.0 · source

pub fn and_then<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> Result<U, E>,

Calls op if the result is Ok, otherwise returns the Err value of self.

\n

This function can be used for control flow based on Result values.

\n
Examples
\n
fn sq_then_to_string(x: u32) -> Result<String, &'static str> {\n    x.checked_mul(x).map(|sq| sq.to_string()).ok_or(\"overflowed\")\n}\n\nassert_eq!(Ok(2).and_then(sq_then_to_string), Ok(4.to_string()));\nassert_eq!(Ok(1_000_000).and_then(sq_then_to_string), Err(\"overflowed\"));\nassert_eq!(Err(\"not a number\").and_then(sq_then_to_string), Err(\"not a number\"));
\n

Often used to chain fallible operations that may return Err.

\n\n
use std::{io::ErrorKind, path::Path};\n\n// Note: on Windows \"/\" maps to \"C:\\\"\nlet root_modified_time = Path::new(\"/\").metadata().and_then(|md| md.modified());\nassert!(root_modified_time.is_ok());\n\nlet should_fail = Path::new(\"/bad/path\").metadata().and_then(|md| md.modified());\nassert!(should_fail.is_err());\nassert_eq!(should_fail.unwrap_err().kind(), ErrorKind::NotFound);
\n
1.0.0 · source

pub fn or<F>(self, res: Result<T, F>) -> Result<T, F>

Returns res if the result is Err, otherwise returns the Ok value of self.

\n

Arguments passed to or are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use or_else, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<u32, &str> = Ok(2);\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Ok(100);\nassert_eq!(x.or(y), Ok(2));
\n
1.0.0 · source

pub fn or_else<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> Result<T, F>,

Calls op if the result is Err, otherwise returns the Ok value of self.

\n

This function can be used for control flow based on result values.

\n
Examples
\n
fn sq(x: u32) -> Result<u32, u32> { Ok(x * x) }\nfn err(x: u32) -> Result<u32, u32> { Err(x) }\n\nassert_eq!(Ok(2).or_else(sq).or_else(sq), Ok(2));\nassert_eq!(Ok(2).or_else(err).or_else(sq), Ok(2));\nassert_eq!(Err(3).or_else(sq).or_else(err), Ok(9));\nassert_eq!(Err(3).or_else(err).or_else(err), Err(3));
\n
1.0.0 · source

pub fn unwrap_or(self, default: T) -> T

Returns the contained Ok value or a provided default.

\n

Arguments passed to unwrap_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use unwrap_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let default = 2;\nlet x: Result<u32, &str> = Ok(9);\nassert_eq!(x.unwrap_or(default), 9);\n\nlet x: Result<u32, &str> = Err(\"error\");\nassert_eq!(x.unwrap_or(default), default);
\n
1.0.0 · source

pub fn unwrap_or_else<F>(self, op: F) -> T
where\n F: FnOnce(E) -> T,

Returns the contained Ok value or computes it from a closure.

\n
Examples
\n
fn count(x: &str) -> usize { x.len() }\n\nassert_eq!(Ok(2).unwrap_or_else(count), 2);\nassert_eq!(Err(\"foo\").unwrap_or_else(count), 3);
\n
1.58.0 · source

pub unsafe fn unwrap_unchecked(self) -> T

Returns the contained Ok value, consuming the self value,\nwithout checking that the value is not an Err.

\n
Safety
\n

Calling this method on an Err is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(unsafe { x.unwrap_unchecked() }, 2);
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nunsafe { x.unwrap_unchecked(); } // Undefined behavior!
\n
1.58.0 · source

pub unsafe fn unwrap_err_unchecked(self) -> E

Returns the contained Err value, consuming the self value,\nwithout checking that the value is not an Ok.

\n
Safety
\n

Calling this method on an Ok is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nunsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(unsafe { x.unwrap_err_unchecked() }, \"emergency failure\");
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<&T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let val = 12;\nlet x: Result<&i32, i32> = Ok(&val);\nassert_eq!(x, Ok(&12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<&mut T, E>

1.59.0 · source

pub fn copied(self) -> Result<T, E>
where\n T: Copy,

Maps a Result<&mut T, E> to a Result<T, E> by copying the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet copied = x.copied();\nassert_eq!(copied, Ok(12));
\n
1.59.0 · source

pub fn cloned(self) -> Result<T, E>
where\n T: Clone,

Maps a Result<&mut T, E> to a Result<T, E> by cloning the contents of the\nOk part.

\n
Examples
\n
let mut val = 12;\nlet x: Result<&mut i32, i32> = Ok(&mut val);\nassert_eq!(x, Ok(&mut 12));\nlet cloned = x.cloned();\nassert_eq!(cloned, Ok(12));
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<Option<T>, E>

1.33.0 (const: unstable) · source

pub fn transpose(self) -> Option<Result<T, E>>

Transposes a Result of an Option into an Option of a Result.

\n

Ok(None) will be mapped to None.\nOk(Some(_)) and Err(_) will be mapped to Some(Ok(_)) and Some(Err(_)).

\n
Examples
\n
#[derive(Debug, Eq, PartialEq)]\nstruct SomeErr;\n\nlet x: Result<Option<i32>, SomeErr> = Ok(Some(5));\nlet y: Option<Result<i32, SomeErr>> = Some(Ok(5));\nassert_eq!(x.transpose(), y);
\n
",0,"clap_builder::error::Result"],["
source§

impl<T, E> Result<Result<T, E>, E>

source

pub fn flatten(self) -> Result<T, E>

🔬This is a nightly-only experimental API. (result_flattening)

Converts from Result<Result<T, E>, E> to Result<T, E>

\n
Examples
\n
#![feature(result_flattening)]\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Ok(\"hello\"));\nassert_eq!(Ok(\"hello\"), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Ok(Err(6));\nassert_eq!(Err(6), x.flatten());\n\nlet x: Result<Result<&'static str, u32>, u32> = Err(6);\nassert_eq!(Err(6), x.flatten());
\n

Flattening only removes one level of nesting at a time:

\n\n
#![feature(result_flattening)]\nlet x: Result<Result<Result<&'static str, u32>, u32>, u32> = Ok(Ok(Ok(\"hello\")));\nassert_eq!(Ok(Ok(\"hello\")), x.flatten());\nassert_eq!(Ok(\"hello\"), x.flatten().flatten());
\n
",0,"clap_builder::error::Result"],["
1.61.0 · source§

impl<T, E> Termination for Result<T, E>
where\n T: Termination,\n E: Debug,

source§

fn report(self) -> ExitCode

Is called to get the representation of the value as status code.\nThis status code is returned to the operating system.
","Termination","clap_builder::error::Result"],["
source§

impl<T, E> Try for Result<T, E>

§

type Output = T

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value produced by ? when not short-circuiting.
§

type Residual = Result<Infallible, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value passed to FromResidual::from_residual\nas part of ? when short-circuiting. Read more
source§

fn from_output(output: <Result<T, E> as Try>::Output) -> Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from its Output type. Read more
source§

fn branch(\n self\n) -> ControlFlow<<Result<T, E> as Try>::Residual, <Result<T, E> as Try>::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)
Used in ? to decide whether the operator should produce a value\n(because this returned ControlFlow::Continue)\nor propagate a value back to the caller\n(because this returned ControlFlow::Break). Read more
","Try","clap_builder::error::Result"],["
1.16.0 · source§

impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
where\n T: Sum<U>,

source§

fn sum<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the sum of all elements is returned.

\n
Examples
\n

This sums up every integer in a vector, rejecting the sum if a negative\nelement is encountered:

\n\n
let f = |&x: &i32| if x < 0 { Err(\"Negative element found\") } else { Ok(x) };\nlet v = vec![1, 2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Ok(3));\nlet v = vec![1, -2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Err(\"Negative element found\"));
\n
","Sum>","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Debug for Result<T, E>
where\n T: Debug,\n E: Debug,

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
","Debug","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Clone for Result<T, E>
where\n T: Clone,\n E: Clone,

source§

fn clone(&self) -> Result<T, E>

Returns a copy of the value. Read more
source§

fn clone_from(&mut self, source: &Result<T, E>)

Performs copy-assignment from source. Read more
","Clone","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> StructuralEq for Result<T, E>

","StructuralEq","clap_builder::error::Result"],["
1.16.0 · source§

impl<T, U, E> Product<Result<U, E>> for Result<T, E>
where\n T: Product<U>,

source§

fn product<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the product of all elements is returned.

\n
Examples
\n

This multiplies each number in a vector of strings,\nif a string could not be parsed the operation returns Err:

\n\n
let nums = vec![\"5\", \"10\", \"1\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert_eq!(total, Ok(100));\nlet nums = vec![\"5\", \"10\", \"one\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert!(total.is_err());
\n
","Product>","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Eq for Result<T, E>
where\n T: Eq,\n E: Eq,

","Eq","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Ord for Result<T, E>
where\n T: Ord,\n E: Ord,

source§

fn cmp(&self, other: &Result<T, E>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Self
where\n Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
","Ord","clap_builder::error::Result"],["
source§

impl<T, E> Residual<T> for Result<Infallible, E>

§

type TryType = Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2_residual)
The “return” type of this meta-function.
","Residual","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> PartialEq for Result<T, E>
where\n T: PartialEq,\n E: PartialEq,

source§

fn eq(&self, other: &Result<T, E>) -> bool

This method tests for self and other values to be equal, and is used\nby ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always\nsufficient, and should not be overridden without very good reason.
","PartialEq","clap_builder::error::Result"],["
1.0.0 · source§

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>
where\n V: FromIterator<A>,

source§

fn from_iter<I>(iter: I) -> Result<V, E>
where\n I: IntoIterator<Item = Result<A, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err occur, a\ncontainer with the values of each Result is returned.

\n

Here is an example which increments every integer in a vector,\nchecking for overflow:

\n\n
let v = vec![1, 2];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_add(1).ok_or(\"Overflow!\")\n).collect();\nassert_eq!(res, Ok(vec![2, 3]));
\n

Here is another example that tries to subtract one from another list\nof integers, this time checking for underflow:

\n\n
let v = vec![1, 2, 0];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_sub(1).ok_or(\"Underflow!\")\n).collect();\nassert_eq!(res, Err(\"Underflow!\"));
\n

Here is a variation on the previous example, showing that no\nfurther elements are taken from iter after the first Err.

\n\n
let v = vec![3, 2, 1, 10];\nlet mut shared = 0;\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32| {\n    shared += x;\n    x.checked_sub(2).ok_or(\"Underflow!\")\n}).collect();\nassert_eq!(res, Err(\"Underflow!\"));\nassert_eq!(shared, 6);
\n

Since the third element caused an underflow, no further elements were taken,\nso the final value of shared is 6 (= 3 + 2 + 1), not 16.

\n
","FromIterator>","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> StructuralPartialEq for Result<T, E>

","StructuralPartialEq","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Copy for Result<T, E>
where\n T: Copy,\n E: Copy,

","Copy","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> Hash for Result<T, E>
where\n T: Hash,\n E: Hash,

source§

fn hash<__H>(&self, state: &mut __H)
where\n __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)
where\n H: Hasher,\n Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
","Hash","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> IntoIterator for Result<T, E>

source§

fn into_iter(self) -> IntoIter<T>

Returns a consuming iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(5);\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, [5]);\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, []);
\n
§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
","IntoIterator","clap_builder::error::Result"],["
1.0.0 · source§

impl<T, E> PartialOrd for Result<T, E>
where\n T: PartialOrd,\n E: PartialOrd,

source§

fn partial_cmp(&self, other: &Result<T, E>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <=\noperator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >=\noperator. Read more
","PartialOrd","clap_builder::error::Result"],["
source§

impl<T, E, F> FromResidual<Yeet<E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(_: Yeet<E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","clap_builder::error::Result"],["
source§

impl<T, E, F> FromResidual<Result<Infallible, E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(residual: Result<Infallible, E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","clap_builder::error::Result"],["
source§

impl From<StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From","clap_builder::error::Result"],["
source§

impl From<&StreamResult> for Result<MZStatus, MZError>

source§

fn from(res: &StreamResult) -> Result<MZStatus, MZError>

Converts to this type from the input type.
","From<&StreamResult>","clap_builder::error::Result"]], "flate2":[], "miniz_oxide":[["
source§

impl<T, E> Result<T, E>

1.0.0 (const: 1.48.0) · source

pub const fn is_ok(&self) -> bool

Returns true if the result is Ok.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_ok(), true);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_ok(), false);
\n
1.70.0 · source

pub fn is_ok_and(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the result is Ok and the value inside of it matches a predicate.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.is_ok_and(|x| x > 1), true);\n\nlet x: Result<u32, &str> = Ok(0);\nassert_eq!(x.is_ok_and(|x| x > 1), false);\n\nlet x: Result<u32, &str> = Err(\"hey\");\nassert_eq!(x.is_ok_and(|x| x > 1), false);
\n
1.0.0 (const: 1.48.0) · source

pub const fn is_err(&self) -> bool

Returns true if the result is Err.

\n
Examples
\n
let x: Result<i32, &str> = Ok(-3);\nassert_eq!(x.is_err(), false);\n\nlet x: Result<i32, &str> = Err(\"Some error message\");\nassert_eq!(x.is_err(), true);
\n
1.70.0 · source

pub fn is_err_and(self, f: impl FnOnce(E) -> bool) -> bool

Returns true if the result is Err and the value inside of it matches a predicate.

\n
Examples
\n
use std::io::{Error, ErrorKind};\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), true);\n\nlet x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, \"!\"));\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);\n\nlet x: Result<u32, Error> = Ok(123);\nassert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);
\n
1.0.0 · source

pub fn ok(self) -> Option<T>

Converts from Result<T, E> to Option<T>.

\n

Converts self into an Option<T>, consuming self,\nand discarding the error, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.ok(), Some(2));\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.ok(), None);
\n
1.0.0 · source

pub fn err(self) -> Option<E>

Converts from Result<T, E> to Option<E>.

\n

Converts self into an Option<E>, consuming self,\nand discarding the success value, if any.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.err(), None);\n\nlet x: Result<u32, &str> = Err(\"Nothing here\");\nassert_eq!(x.err(), Some(\"Nothing here\"));
\n
1.0.0 (const: 1.48.0) · source

pub const fn as_ref(&self) -> Result<&T, &E>

Converts from &Result<T, E> to Result<&T, &E>.

\n

Produces a new Result, containing a reference\ninto the original, leaving the original in place.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.as_ref(), Ok(&2));\n\nlet x: Result<u32, &str> = Err(\"Error\");\nassert_eq!(x.as_ref(), Err(&\"Error\"));
\n
1.0.0 (const: unstable) · source

pub fn as_mut(&mut self) -> Result<&mut T, &mut E>

Converts from &mut Result<T, E> to Result<&mut T, &mut E>.

\n
Examples
\n
fn mutate(r: &mut Result<i32, i32>) {\n    match r.as_mut() {\n        Ok(v) => *v = 42,\n        Err(e) => *e = 0,\n    }\n}\n\nlet mut x: Result<i32, i32> = Ok(2);\nmutate(&mut x);\nassert_eq!(x.unwrap(), 42);\n\nlet mut x: Result<i32, i32> = Err(13);\nmutate(&mut x);\nassert_eq!(x.unwrap_err(), 0);
\n
1.0.0 · source

pub fn map<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> U,

Maps a Result<T, E> to Result<U, E> by applying a function to a\ncontained Ok value, leaving an Err value untouched.

\n

This function can be used to compose the results of two functions.

\n
Examples
\n

Print the numbers on each line of a string multiplied by two.

\n\n
let line = \"1\\n2\\n3\\n4\\n\";\n\nfor num in line.lines() {\n    match num.parse::<i32>().map(|i| i * 2) {\n        Ok(n) => println!(\"{n}\"),\n        Err(..) => {}\n    }\n}
\n
1.41.0 · source

pub fn map_or<U, F>(self, default: U, f: F) -> U
where\n F: FnOnce(T) -> U,

Returns the provided default (if Err), or\napplies a function to the contained value (if Ok).

\n

Arguments passed to map_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use map_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let x: Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or(42, |v| v.len()), 3);\n\nlet x: Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or(42, |v| v.len()), 42);
\n
1.41.0 · source

pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
where\n D: FnOnce(E) -> U,\n F: FnOnce(T) -> U,

Maps a Result<T, E> to U by applying fallback function default to\na contained Err value, or function f to a contained Ok value.

\n

This function can be used to unpack a successful result\nwhile handling an error.

\n
Examples
\n
let k = 21;\n\nlet x : Result<_, &str> = Ok(\"foo\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 3);\n\nlet x : Result<&str, _> = Err(\"bar\");\nassert_eq!(x.map_or_else(|e| k * 2, |v| v.len()), 42);
\n
1.0.0 · source

pub fn map_err<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> F,

Maps a Result<T, E> to Result<T, F> by applying a function to a\ncontained Err value, leaving an Ok value untouched.

\n

This function can be used to pass through a successful result while handling\nan error.

\n
Examples
\n
fn stringify(x: u32) -> String { format!(\"error code: {x}\") }\n\nlet x: Result<u32, u32> = Ok(2);\nassert_eq!(x.map_err(stringify), Ok(2));\n\nlet x: Result<u32, u32> = Err(13);\nassert_eq!(x.map_err(stringify), Err(\"error code: 13\".to_string()));
\n
1.76.0 · source

pub fn inspect<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&T),

Calls the provided closure with a reference to the contained value (if Ok).

\n
Examples
\n
let x: u8 = \"4\"\n    .parse::<u8>()\n    .inspect(|x| println!(\"original: {x}\"))\n    .map(|x| x.pow(3))\n    .expect(\"failed to parse number\");
\n
1.76.0 · source

pub fn inspect_err<F>(self, f: F) -> Result<T, E>
where\n F: FnOnce(&E),

Calls the provided closure with a reference to the contained error (if Err).

\n
Examples
\n
use std::{fs, io};\n\nfn read() -> io::Result<String> {\n    fs::read_to_string(\"address.txt\")\n        .inspect_err(|e| eprintln!(\"failed to read file: {e}\"))\n}
\n
1.47.0 · source

pub fn as_deref(&self) -> Result<&<T as Deref>::Target, &E>
where\n T: Deref,

Converts from Result<T, E> (or &Result<T, E>) to Result<&<T as Deref>::Target, &E>.

\n

Coerces the Ok variant of the original Result via Deref\nand returns the new Result.

\n
Examples
\n
let x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&str, &u32> = Ok(\"hello\");\nassert_eq!(x.as_deref(), y);\n\nlet x: Result<String, u32> = Err(42);\nlet y: Result<&str, &u32> = Err(&42);\nassert_eq!(x.as_deref(), y);
\n
1.47.0 · source

pub fn as_deref_mut(&mut self) -> Result<&mut <T as Deref>::Target, &mut E>
where\n T: DerefMut,

Converts from Result<T, E> (or &mut Result<T, E>) to Result<&mut <T as DerefMut>::Target, &mut E>.

\n

Coerces the Ok variant of the original Result via DerefMut\nand returns the new Result.

\n
Examples
\n
let mut s = \"HELLO\".to_string();\nlet mut x: Result<String, u32> = Ok(\"hello\".to_string());\nlet y: Result<&mut str, &mut u32> = Ok(&mut s);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);\n\nlet mut i = 42;\nlet mut x: Result<String, u32> = Err(42);\nlet y: Result<&mut str, &mut u32> = Err(&mut i);\nassert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
\n
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(7);\nassert_eq!(x.iter().next(), Some(&7));\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter().next(), None);
\n
1.0.0 · source

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns a mutable iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let mut x: Result<u32, &str> = Ok(7);\nmatch x.iter_mut().next() {\n    Some(v) => *v = 40,\n    None => {},\n}\nassert_eq!(x, Ok(40));\n\nlet mut x: Result<u32, &str> = Err(\"nothing!\");\nassert_eq!(x.iter_mut().next(), None);
\n
1.4.0 · source

pub fn expect(self, msg: &str) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message including the\npassed message, and the content of the Err.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.expect(\"Testing expect\"); // panics with `Testing expect: emergency failure`
\n
Recommended Message Style
\n

We recommend that expect messages are used to describe the reason you\nexpect the Result should be Ok.

\n\n
ⓘ
let path = std::env::var(\"IMPORTANT_PATH\")\n    .expect(\"env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`\");
\n

Hint: If you’re having trouble remembering how to phrase expect\nerror messages remember to focus on the word “should” as in “env\nvariable should be set by blah” or “the given binary should be available\nand executable by the current user”.

\n

For more detail on expect message styles and the reasoning behind our recommendation please\nrefer to the section on “Common Message\nStyles” in the\nstd::error module docs.

\n
1.0.0 · source

pub fn unwrap(self) -> T
where\n E: Debug,

Returns the contained Ok value, consuming the self value.

\n

Because this function may panic, its use is generally discouraged.\nInstead, prefer to use pattern matching and handle the Err\ncase explicitly, or call unwrap_or, unwrap_or_else, or\nunwrap_or_default.

\n
Panics
\n

Panics if the value is an Err, with a panic message provided by the\nErr’s value.

\n
Examples
\n

Basic usage:

\n\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(x.unwrap(), 2);
\n\n
ⓘ
let x: Result<u32, &str> = Err(\"emergency failure\");\nx.unwrap(); // panics with `emergency failure`
\n
1.16.0 · source

pub fn unwrap_or_default(self) -> T
where\n T: Default,

Returns the contained Ok value or a default

\n

Consumes the self argument then, if Ok, returns the contained\nvalue, otherwise if Err, returns the default value for that\ntype.

\n
Examples
\n

Converts a string to an integer, turning poorly-formed strings\ninto 0 (the default value for integers). parse converts\na string to any other type that implements FromStr, returning an\nErr on error.

\n\n
let good_year_from_input = \"1909\";\nlet bad_year_from_input = \"190blarg\";\nlet good_year = good_year_from_input.parse().unwrap_or_default();\nlet bad_year = bad_year_from_input.parse().unwrap_or_default();\n\nassert_eq!(1909, good_year);\nassert_eq!(0, bad_year);
\n
1.17.0 · source

pub fn expect_err(self, msg: &str) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a panic message including the\npassed message, and the content of the Ok.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(10);\nx.expect_err(\"Testing expect_err\"); // panics with `Testing expect_err: 10`
\n
1.0.0 · source

pub fn unwrap_err(self) -> E
where\n T: Debug,

Returns the contained Err value, consuming the self value.

\n
Panics
\n

Panics if the value is an Ok, with a custom panic message provided\nby the Ok’s value.

\n
Examples
\n
ⓘ
let x: Result<u32, &str> = Ok(2);\nx.unwrap_err(); // panics with `2`
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(x.unwrap_err(), \"emergency failure\");
\n
source

pub fn into_ok(self) -> T
where\n E: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Ok value, but never panics.

\n

Unlike unwrap, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap as a maintainability safeguard that will fail\nto compile if the error type of the Result is later changed\nto an error that can actually occur.

\n
Examples
\n
\nfn only_good_news() -> Result<String, !> {\n    Ok(\"this is fine\".into())\n}\n\nlet s: String = only_good_news().into_ok();\nprintln!(\"{s}\");
\n
source

pub fn into_err(self) -> E
where\n T: Into<!>,

🔬This is a nightly-only experimental API. (unwrap_infallible)

Returns the contained Err value, but never panics.

\n

Unlike unwrap_err, this method is known to never panic on the\nresult types it is implemented for. Therefore, it can be used\ninstead of unwrap_err as a maintainability safeguard that will fail\nto compile if the ok type of the Result is later changed\nto a type that can actually occur.

\n
Examples
\n
\nfn only_bad_news() -> Result<!, String> {\n    Err(\"Oops, it failed\".into())\n}\n\nlet error: String = only_bad_news().into_err();\nprintln!(\"{error}\");
\n
1.0.0 · source

pub fn and<U>(self, res: Result<U, E>) -> Result<U, E>

Returns res if the result is Ok, otherwise returns the Err value of self.

\n

Arguments passed to and are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use and_then, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<&str, &str> = Ok(\"foo\");\nassert_eq!(x.and(y), Err(\"early error\"));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<&str, &str> = Err(\"late error\");\nassert_eq!(x.and(y), Err(\"not a 2\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<&str, &str> = Ok(\"different result type\");\nassert_eq!(x.and(y), Ok(\"different result type\"));
\n
1.0.0 · source

pub fn and_then<U, F>(self, op: F) -> Result<U, E>
where\n F: FnOnce(T) -> Result<U, E>,

Calls op if the result is Ok, otherwise returns the Err value of self.

\n

This function can be used for control flow based on Result values.

\n
Examples
\n
fn sq_then_to_string(x: u32) -> Result<String, &'static str> {\n    x.checked_mul(x).map(|sq| sq.to_string()).ok_or(\"overflowed\")\n}\n\nassert_eq!(Ok(2).and_then(sq_then_to_string), Ok(4.to_string()));\nassert_eq!(Ok(1_000_000).and_then(sq_then_to_string), Err(\"overflowed\"));\nassert_eq!(Err(\"not a number\").and_then(sq_then_to_string), Err(\"not a number\"));
\n

Often used to chain fallible operations that may return Err.

\n\n
use std::{io::ErrorKind, path::Path};\n\n// Note: on Windows \"/\" maps to \"C:\\\"\nlet root_modified_time = Path::new(\"/\").metadata().and_then(|md| md.modified());\nassert!(root_modified_time.is_ok());\n\nlet should_fail = Path::new(\"/bad/path\").metadata().and_then(|md| md.modified());\nassert!(should_fail.is_err());\nassert_eq!(should_fail.unwrap_err().kind(), ErrorKind::NotFound);
\n
1.0.0 · source

pub fn or<F>(self, res: Result<T, F>) -> Result<T, F>

Returns res if the result is Err, otherwise returns the Ok value of self.

\n

Arguments passed to or are eagerly evaluated; if you are passing the\nresult of a function call, it is recommended to use or_else, which is\nlazily evaluated.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"early error\");\nlet y: Result<u32, &str> = Ok(2);\nassert_eq!(x.or(y), Ok(2));\n\nlet x: Result<u32, &str> = Err(\"not a 2\");\nlet y: Result<u32, &str> = Err(\"late error\");\nassert_eq!(x.or(y), Err(\"late error\"));\n\nlet x: Result<u32, &str> = Ok(2);\nlet y: Result<u32, &str> = Ok(100);\nassert_eq!(x.or(y), Ok(2));
\n
1.0.0 · source

pub fn or_else<F, O>(self, op: O) -> Result<T, F>
where\n O: FnOnce(E) -> Result<T, F>,

Calls op if the result is Err, otherwise returns the Ok value of self.

\n

This function can be used for control flow based on result values.

\n
Examples
\n
fn sq(x: u32) -> Result<u32, u32> { Ok(x * x) }\nfn err(x: u32) -> Result<u32, u32> { Err(x) }\n\nassert_eq!(Ok(2).or_else(sq).or_else(sq), Ok(2));\nassert_eq!(Ok(2).or_else(err).or_else(sq), Ok(2));\nassert_eq!(Err(3).or_else(sq).or_else(err), Ok(9));\nassert_eq!(Err(3).or_else(err).or_else(err), Err(3));
\n
1.0.0 · source

pub fn unwrap_or(self, default: T) -> T

Returns the contained Ok value or a provided default.

\n

Arguments passed to unwrap_or are eagerly evaluated; if you are passing\nthe result of a function call, it is recommended to use unwrap_or_else,\nwhich is lazily evaluated.

\n
Examples
\n
let default = 2;\nlet x: Result<u32, &str> = Ok(9);\nassert_eq!(x.unwrap_or(default), 9);\n\nlet x: Result<u32, &str> = Err(\"error\");\nassert_eq!(x.unwrap_or(default), default);
\n
1.0.0 · source

pub fn unwrap_or_else<F>(self, op: F) -> T
where\n F: FnOnce(E) -> T,

Returns the contained Ok value or computes it from a closure.

\n
Examples
\n
fn count(x: &str) -> usize { x.len() }\n\nassert_eq!(Ok(2).unwrap_or_else(count), 2);\nassert_eq!(Err(\"foo\").unwrap_or_else(count), 3);
\n
1.58.0 · source

pub unsafe fn unwrap_unchecked(self) -> T

Returns the contained Ok value, consuming the self value,\nwithout checking that the value is not an Err.

\n
Safety
\n

Calling this method on an Err is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nassert_eq!(unsafe { x.unwrap_unchecked() }, 2);
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nunsafe { x.unwrap_unchecked(); } // Undefined behavior!
\n
1.58.0 · source

pub unsafe fn unwrap_err_unchecked(self) -> E

Returns the contained Err value, consuming the self value,\nwithout checking that the value is not an Ok.

\n
Safety
\n

Calling this method on an Ok is undefined behavior.

\n
Examples
\n
let x: Result<u32, &str> = Ok(2);\nunsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
\n\n
let x: Result<u32, &str> = Err(\"emergency failure\");\nassert_eq!(unsafe { x.unwrap_err_unchecked() }, \"emergency failure\");
\n
",0,"miniz_oxide::MZResult"],["
source§

impl<T, E> Try for Result<T, E>

§

type Output = T

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value produced by ? when not short-circuiting.
§

type Residual = Result<Infallible, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
The type of the value passed to FromResidual::from_residual\nas part of ? when short-circuiting. Read more
source§

fn from_output(output: <Result<T, E> as Try>::Output) -> Result<T, E>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from its Output type. Read more
source§

fn branch(\n self\n) -> ControlFlow<<Result<T, E> as Try>::Residual, <Result<T, E> as Try>::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)
Used in ? to decide whether the operator should produce a value\n(because this returned ControlFlow::Continue)\nor propagate a value back to the caller\n(because this returned ControlFlow::Break). Read more
","Try","miniz_oxide::MZResult"],["
1.16.0 · source§

impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
where\n T: Sum<U>,

source§

fn sum<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the sum of all elements is returned.

\n
Examples
\n

This sums up every integer in a vector, rejecting the sum if a negative\nelement is encountered:

\n\n
let f = |&x: &i32| if x < 0 { Err(\"Negative element found\") } else { Ok(x) };\nlet v = vec![1, 2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Ok(3));\nlet v = vec![1, -2];\nlet res: Result<i32, _> = v.iter().map(f).sum();\nassert_eq!(res, Err(\"Negative element found\"));
\n
","Sum>","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> Debug for Result<T, E>
where\n T: Debug,\n E: Debug,

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
","Debug","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> Clone for Result<T, E>
where\n T: Clone,\n E: Clone,

source§

fn clone(&self) -> Result<T, E>

Returns a copy of the value. Read more
source§

fn clone_from(&mut self, source: &Result<T, E>)

Performs copy-assignment from source. Read more
","Clone","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> StructuralEq for Result<T, E>

","StructuralEq","miniz_oxide::MZResult"],["
1.16.0 · source§

impl<T, U, E> Product<Result<U, E>> for Result<T, E>
where\n T: Product<U>,

source§

fn product<I>(iter: I) -> Result<T, E>
where\n I: Iterator<Item = Result<U, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err\noccur, the product of all elements is returned.

\n
Examples
\n

This multiplies each number in a vector of strings,\nif a string could not be parsed the operation returns Err:

\n\n
let nums = vec![\"5\", \"10\", \"1\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert_eq!(total, Ok(100));\nlet nums = vec![\"5\", \"10\", \"one\", \"2\"];\nlet total: Result<usize, _> = nums.iter().map(|w| w.parse::<usize>()).product();\nassert!(total.is_err());
\n
","Product>","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> Eq for Result<T, E>
where\n T: Eq,\n E: Eq,

","Eq","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> Ord for Result<T, E>
where\n T: Ord,\n E: Ord,

source§

fn cmp(&self, other: &Result<T, E>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Self
where\n Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Self
where\n Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
","Ord","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> PartialEq for Result<T, E>
where\n T: PartialEq,\n E: PartialEq,

source§

fn eq(&self, other: &Result<T, E>) -> bool

This method tests for self and other values to be equal, and is used\nby ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always\nsufficient, and should not be overridden without very good reason.
","PartialEq","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>
where\n V: FromIterator<A>,

source§

fn from_iter<I>(iter: I) -> Result<V, E>
where\n I: IntoIterator<Item = Result<A, E>>,

Takes each element in the Iterator: if it is an Err, no further\nelements are taken, and the Err is returned. Should no Err occur, a\ncontainer with the values of each Result is returned.

\n

Here is an example which increments every integer in a vector,\nchecking for overflow:

\n\n
let v = vec![1, 2];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_add(1).ok_or(\"Overflow!\")\n).collect();\nassert_eq!(res, Ok(vec![2, 3]));
\n

Here is another example that tries to subtract one from another list\nof integers, this time checking for underflow:

\n\n
let v = vec![1, 2, 0];\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32|\n    x.checked_sub(1).ok_or(\"Underflow!\")\n).collect();\nassert_eq!(res, Err(\"Underflow!\"));
\n

Here is a variation on the previous example, showing that no\nfurther elements are taken from iter after the first Err.

\n\n
let v = vec![3, 2, 1, 10];\nlet mut shared = 0;\nlet res: Result<Vec<u32>, &'static str> = v.iter().map(|x: &u32| {\n    shared += x;\n    x.checked_sub(2).ok_or(\"Underflow!\")\n}).collect();\nassert_eq!(res, Err(\"Underflow!\"));\nassert_eq!(shared, 6);
\n

Since the third element caused an underflow, no further elements were taken,\nso the final value of shared is 6 (= 3 + 2 + 1), not 16.

\n
","FromIterator>","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> StructuralPartialEq for Result<T, E>

","StructuralPartialEq","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> Copy for Result<T, E>
where\n T: Copy,\n E: Copy,

","Copy","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> Hash for Result<T, E>
where\n T: Hash,\n E: Hash,

source§

fn hash<__H>(&self, state: &mut __H)
where\n __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)
where\n H: Hasher,\n Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
","Hash","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> IntoIterator for Result<T, E>

source§

fn into_iter(self) -> IntoIter<T>

Returns a consuming iterator over the possibly contained value.

\n

The iterator yields one value if the result is Result::Ok, otherwise none.

\n
Examples
\n
let x: Result<u32, &str> = Ok(5);\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, [5]);\n\nlet x: Result<u32, &str> = Err(\"nothing!\");\nlet v: Vec<u32> = x.into_iter().collect();\nassert_eq!(v, []);
\n
§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
","IntoIterator","miniz_oxide::MZResult"],["
1.0.0 · source§

impl<T, E> PartialOrd for Result<T, E>
where\n T: PartialOrd,\n E: PartialOrd,

source§

fn partial_cmp(&self, other: &Result<T, E>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <=\noperator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >=\noperator. Read more
","PartialOrd","miniz_oxide::MZResult"],["
source§

impl<T, E, F> FromResidual<Yeet<E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(_: Yeet<E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","miniz_oxide::MZResult"],["
source§

impl<T, E, F> FromResidual<Result<Infallible, E>> for Result<T, F>
where\n F: From<E>,

source§

fn from_residual(residual: Result<Infallible, E>) -> Result<T, F>

🔬This is a nightly-only experimental API. (try_trait_v2)
Constructs the type from a compatible Residual type. Read more
","FromResidual>","miniz_oxide::MZResult"]], "serde":[],