perf: use str instead of Cow to reduse Token size

pest-parser · Jan 3, 2024 · 5ccddd2 · 5ccddd2
1 parent ab70fe6
commit 5ccddd2
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Showing 3 changed files with 15 additions and 17 deletions.
diff --git a/pest/src/iterators/pairs.rs b/pest/src/iterators/pairs.rs
@@ -227,9 +227,9 @@ impl<'i, R: RuleType> Pairs<'i, R> {
     ///     state: Box<ParserState<'_, Rule>>,
     /// ) -> ParseResult<Box<ParserState<'_, Rule>>> {
     ///     expr(state, Rule::mul, "*")
-    ///         .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("mul")))
+    ///         .and_then(|state| state.tag_node("mul"))
     ///         .or_else(|state| expr(state, Rule::add, "+"))
-    ///         .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("add")))
+    ///         .and_then(|state| state.tag_node("add"))
     /// }
     /// fn expr<'a>(
     ///     state: Box<ParserState<'a, Rule>>,
@@ -239,10 +239,10 @@ impl<'i, R: RuleType> Pairs<'i, R> {
     ///     state.rule(r, |state| {
     ///         state.sequence(|state| {
     ///             number(state)
-    ///                 .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("lhs")))
+    ///                 .and_then(|state| state.tag_node("lhs"))
     ///                 .and_then(|state| state.match_string(o))
     ///                 .and_then(number)
-    ///                 .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("rhs")))
+    ///                 .and_then(|state| state.tag_node("rhs"))
     ///         })
     ///     })
     /// }
@@ -278,9 +278,9 @@ impl<'i, R: RuleType> Pairs<'i, R> {
     ///     state: Box<ParserState<'_, Rule>>,
     /// ) -> ParseResult<Box<ParserState<'_, Rule>>> {
     ///     expr(state, Rule::mul, "*")
-    ///         .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("mul")))
+    ///         .and_then(|state| state.tag_node("mul"))
     ///         .or_else(|state| expr(state, Rule::add, "+"))
-    ///         .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("add")))
+    ///         .and_then(|state| state.tag_node("add"))
     /// }
     /// fn expr<'a>(
     ///     state: Box<ParserState<'a, Rule>>,
@@ -290,10 +290,10 @@ impl<'i, R: RuleType> Pairs<'i, R> {
     ///     state.rule(r, |state| {
     ///         state.sequence(|state| {
     ///             number(state)
-    ///                 .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("lhs")))
+    ///                 .and_then(|state| state.tag_node("lhs"))
     ///                 .and_then(|state| state.match_string(o))
     ///                 .and_then(number)
-    ///                 .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("rhs")))
+    ///                 .and_then(|state| state.tag_node("rhs"))
     ///         })
     ///     })
     /// }
@@ -676,9 +676,9 @@ mod tests {
             state: Box<ParserState<'_, Rule>>,
         ) -> ParseResult<Box<ParserState<'_, Rule>>> {
             expr(state, Rule::mul, "*")
-                .and_then(|state| state.tag_node(alloc::borrow::Cow::Borrowed("mul")))
+                .and_then(|state| state.tag_node("mul"))
                 .or_else(|state| expr(state, Rule::add, "+"))
-                .and_then(|state| state.tag_node(alloc::borrow::Cow::Borrowed("add")))
+                .and_then(|state| state.tag_node("add"))
         }
         fn expr<'a>(
             state: Box<ParserState<'a, Rule>>,
@@ -688,10 +688,10 @@ mod tests {
             state.rule(r, |state| {
                 state.sequence(|state| {
                     number(state)
-                        .and_then(|state| state.tag_node(alloc::borrow::Cow::Borrowed("lhs")))
+                        .and_then(|state| state.tag_node("lhs"))
                         .and_then(|state| state.match_string(o))
                         .and_then(number)
-                        .and_then(|state| state.tag_node(alloc::borrow::Cow::Borrowed("rhs")))
+                        .and_then(|state| state.tag_node("rhs"))
                 })
             })
         }

diff --git a/pest/src/iterators/queueable_token.rs b/pest/src/iterators/queueable_token.rs
@@ -7,8 +7,6 @@
 // option. All files in the project carrying such notice may not be copied,
 // modified, or distributed except according to those terms.
 
-use alloc::borrow::Cow;
-
 // This structure serves to improve performance over Token objects in two ways:
 //
 //   * it is smaller than a Token, leading to both less memory use when stored in the queue but also
@@ -24,7 +22,7 @@ pub enum QueueableToken<'i, R> {
     End {
         start_token_index: usize,
         rule: R,
-        tag: Option<Cow<'i, str>>,
+        tag: Option<&'i str>,
         input_pos: usize,
     },
 }
diff --git a/pest/src/parser_state.rs b/pest/src/parser_state.rs
@@ -392,7 +392,7 @@ impl<'i, R: RuleType> ParserState<'i, R> {
     ///         character(state)
     ///             .and_then(|state| character(state))
     ///             .and_then(|state| character(state))
-    ///             .and_then(|state| state.tag_node(std::borrow::Cow::Borrowed("c")))
+    ///             .and_then(|state| state.tag_node("c"))
     ///             .and_then(|state| character(state))
     ///     })
     /// }
@@ -407,7 +407,7 @@ impl<'i, R: RuleType> ParserState<'i, R> {
     /// assert_eq!(find[0].as_str(), "c")
     /// ```
     #[inline]
-    pub fn tag_node(mut self: Box<Self>, tag: Cow<'i, str>) -> ParseResult<Box<Self>> {
+    pub fn tag_node(mut self: Box<Self>, tag: &'i str) -> ParseResult<Box<Self>> {
         if let Some(QueueableToken::End { tag: old, .. }) = self.queue.last_mut() {
             *old = Some(tag)
         }