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🎨 Refactoring and update docs
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@wrenger
wrenger committed Jan 20, 2023
1 parent 45efe0e commit 0a9129c
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3 changes: 2 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,7 @@ assert_eq!(val.negative(), 1);

The macro generates three accessor functions for each field.
Each accessor also inherits the documentation of its field.

The signatures for `int` are:

```rust
Expand All @@ -103,7 +104,7 @@ struct MyBitfield(u64);
impl MyBitfield {
const fn new() -> Self { Self(0) }

const INT_BITS: usize = 32;
const INT_BITS: usize = 16;
const INT_OFFSET: usize = 0;

const fn with_int(self, value: u16) -> Self { /* ... */ }
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61 changes: 33 additions & 28 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@
//!
//! ## Example
//!
//! The example below shows the main features of the macro and how to use them.
//!
//! ```
//! # use bitfield_struct::bitfield;
//! /// A test bitfield with documentation
Expand Down Expand Up @@ -98,12 +100,12 @@
//! impl MyBitfield {
//! const fn new() -> Self { Self(0) }
//!
//! const INT_BITS: usize = 32;
//! const INT_BITS: usize = 16;
//! const INT_OFFSET: usize = 0;
//!
//! const fn with_int(self, value: u32) -> Self { /* ... */ }
//! const fn int(&self) -> u32 { /* ... */ }
//! fn set_int(&mut self, value: u32) { /* ... */ }
//! const fn with_int(self, value: u16) -> Self { /* ... */ }
//! const fn int(&self) -> u16 { /* ... */ }
//! fn set_int(&mut self, value: u16) { /* ... */ }
//!
//! // other field ...
//! }
Expand All @@ -113,6 +115,8 @@
//! impl Debug for MyBitfield { /* ... */ }
//! ```
//!
//! > Hint: You can use the rust-analyzer "Expand macro recursively" action to view the generated code.
//!
//! ## `fmt::Debug`
//!
//! This macro automatically creates a suitable `fmt::Debug` implementation
Expand Down Expand Up @@ -142,6 +146,7 @@
use proc_macro as pc;
use proc_macro2::{Ident, Span, TokenStream};
use quote::{format_ident, quote, ToTokens};
use std::stringify;
use syn::parse::{Parse, ParseStream};
use syn::spanned::Spanned;
use syn::Token;
Expand All @@ -151,8 +156,8 @@ use syn::Token;
/// The arguments first, have to begin with the underlying type of the bitfield:
/// For example: `#[bitfield(u64)]`.
///
/// Then optionally can contain an extra debug argument, for disabling the automatic Debug trait generation.
/// Like: `#[bitfield(u64, debug = false)]`
/// It can contain an extra `debug` argument for disabling the `Debug` trait
/// generation (`#[bitfield(u64, debug = false)]`).
#[proc_macro_attribute]
pub fn bitfield(args: pc::TokenStream, input: pc::TokenStream) -> pc::TokenStream {
match bitfield_inner(args.into(), input.into()) {
Expand Down Expand Up @@ -410,7 +415,7 @@ impl ToTokens for Member {
/// Parses the `bits` attribute that allows specifying a custom number of bits.
fn bits(attrs: &[syn::Attribute], ty: &syn::Type) -> syn::Result<(TypeClass, usize)> {
fn malformed(mut e: syn::Error, attr: &syn::Attribute) -> syn::Error {
e.combine(syn::Error::new_spanned(attr, "malformed #[bits] attribute"));
e.combine(syn::Error::new(attr.span(), "malformed #[bits] attribute"));
e
}

Expand All @@ -434,7 +439,7 @@ fn bits(attrs: &[syn::Attribute], ty: &syn::Type) -> syn::Result<(TypeClass, usi
if bits <= size {
Ok((class, bits))
} else {
Err(syn::Error::new_spanned(tokens, "overflowing member type"))
Err(syn::Error::new(tokens.span(), "overflowing member type"))
}
} else {
Ok((TypeClass::Other, bits))
Expand All @@ -450,23 +455,24 @@ fn bits(attrs: &[syn::Attribute], ty: &syn::Type) -> syn::Result<(TypeClass, usi

/// Returns the number of bits for a given type
fn type_bits(ty: &syn::Type) -> syn::Result<(TypeClass, usize)> {
use syn::Type::Path;
match ty {
Path(path) if path.path.is_ident("bool") => Ok((TypeClass::Bool, 1)),
Path(path) if path.path.is_ident("u8") => Ok((TypeClass::Int, u8::BITS as _)),
Path(path) if path.path.is_ident("i8") => Ok((TypeClass::Int, i8::BITS as _)),
Path(path) if path.path.is_ident("u16") => Ok((TypeClass::Int, u16::BITS as _)),
Path(path) if path.path.is_ident("i16") => Ok((TypeClass::Int, i16::BITS as _)),
Path(path) if path.path.is_ident("u32") => Ok((TypeClass::Int, u32::BITS as _)),
Path(path) if path.path.is_ident("i32") => Ok((TypeClass::Int, i32::BITS as _)),
Path(path) if path.path.is_ident("u64") => Ok((TypeClass::Int, u64::BITS as _)),
Path(path) if path.path.is_ident("i64") => Ok((TypeClass::Int, i64::BITS as _)),
Path(path) if path.path.is_ident("u128") => Ok((TypeClass::Int, u128::BITS as _)),
Path(path) if path.path.is_ident("i128") => Ok((TypeClass::Int, i128::BITS as _)),
Path(path) if path.path.is_ident("usize") => Ok((TypeClass::Int, usize::BITS as _)),
Path(path) if path.path.is_ident("isize") => Ok((TypeClass::Int, isize::BITS as _)),
_ => Err(syn::Error::new_spanned(ty, "unsupported type")),
let syn::Type::Path(syn::TypePath{ path, .. }) = ty else {
return Err(syn::Error::new(ty.span(), "unsupported type"))
};
let Some(ident) = path.get_ident() else {
return Err(syn::Error::new(ty.span(), "unsupported type"))
};
if ident == "bool" {
return Ok((TypeClass::Bool, 1));
}
macro_rules! integer {
($ident:ident => $($ty:ident),*) => {
match ident {
$(_ if ident == stringify!($ty) => Ok((TypeClass::Int, $ty::BITS as _)),)*
_ => Err(syn::Error::new(ty.span(), "unsupported type"))
}
};
}
integer!(ident => u8, i8, u16, i16, u32, i32, u64, i64, u128, i128, usize, isize)
}

struct Params {
Expand All @@ -481,8 +487,8 @@ impl Parse for Params {
return Err(syn::Error::new(input.span(), "unknown type"));
};
let (class, bits) = type_bits(&ty)?;
if class == TypeClass::Bool {
return Err(syn::Error::new(input.span(), "unknown type"));
if class != TypeClass::Int {
return Err(syn::Error::new(input.span(), "unsupported type"));
}

// try parse additional debug arg
Expand All @@ -494,8 +500,7 @@ impl Parse for Params {
}
<Token![=]>::parse(input)?;

let val = syn::LitBool::parse(input)?;
val.value
syn::LitBool::parse(input)?.value
} else {
true
};
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