bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/tt/src/lib.rs')
-rw-r--r--crates/tt/src/lib.rs52
1 files changed, 31 insertions, 21 deletions
diff --git a/crates/tt/src/lib.rs b/crates/tt/src/lib.rs
index b3b0eeda75..9004bff53a 100644
--- a/crates/tt/src/lib.rs
+++ b/crates/tt/src/lib.rs
@@ -23,10 +23,10 @@ pub enum TokenTree<S> {
}
impl_from!(Leaf<S>, Subtree<S> for TokenTree);
impl<S: Span> TokenTree<S> {
- pub const fn empty(span: S) -> Self {
+ pub fn empty(span: S) -> Self {
Self::Subtree(Subtree {
delimiter: Delimiter::invisible_spanned(span),
- token_trees: vec![],
+ token_trees: Box::new([]),
})
}
@@ -34,7 +34,7 @@ impl<S: Span> TokenTree<S> {
match self {
TokenTree::Leaf(_) => Subtree {
delimiter: Delimiter::invisible_delim_spanned(span),
- token_trees: vec![self],
+ token_trees: Box::new([self]),
},
TokenTree::Subtree(s) => s,
}
@@ -69,25 +69,35 @@ impl_from!(Literal<S>, Punct<S>, Ident<S> for Leaf);
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct Subtree<S> {
pub delimiter: Delimiter<S>,
- pub token_trees: Vec<TokenTree<S>>,
+ pub token_trees: Box<[TokenTree<S>]>,
}
impl<S: Span> Subtree<S> {
- pub const fn empty(span: DelimSpan<S>) -> Self {
- Subtree { delimiter: Delimiter::invisible_delim_spanned(span), token_trees: vec![] }
+ pub fn empty(span: DelimSpan<S>) -> Self {
+ Subtree { delimiter: Delimiter::invisible_delim_spanned(span), token_trees: Box::new([]) }
}
- pub fn visit_ids(&mut self, f: &mut impl FnMut(S) -> S) {
- self.delimiter.open = f(self.delimiter.open);
- self.delimiter.close = f(self.delimiter.close);
- self.token_trees.iter_mut().for_each(|tt| match tt {
- crate::TokenTree::Leaf(leaf) => match leaf {
- crate::Leaf::Literal(it) => it.span = f(it.span),
- crate::Leaf::Punct(it) => it.span = f(it.span),
- crate::Leaf::Ident(it) => it.span = f(it.span),
- },
- crate::TokenTree::Subtree(s) => s.visit_ids(f),
- })
+ /// This is slow, and should be avoided, as it will always reallocate!
+ pub fn push(&mut self, subtree: TokenTree<S>) {
+ let mut mutable_trees = std::mem::take(&mut self.token_trees).into_vec();
+
+ // Reserve exactly space for one element, to avoid `into_boxed_slice` having to reallocate again.
+ mutable_trees.reserve_exact(1);
+ mutable_trees.push(subtree);
+
+ self.token_trees = mutable_trees.into_boxed_slice();
+ }
+}
+
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct SubtreeBuilder<S> {
+ pub delimiter: Delimiter<S>,
+ pub token_trees: Vec<TokenTree<S>>,
+}
+
+impl<S> SubtreeBuilder<S> {
+ pub fn build(self) -> Subtree<S> {
+ Subtree { delimiter: self.delimiter, token_trees: self.token_trees.into_boxed_slice() }
}
}
@@ -241,7 +251,7 @@ impl<S> fmt::Display for Subtree<S> {
};
f.write_str(l)?;
let mut needs_space = false;
- for tt in &self.token_trees {
+ for tt in self.token_trees.iter() {
if needs_space {
f.write_str(" ")?;
}
@@ -316,7 +326,7 @@ impl<S> Subtree<S> {
let mut res = String::new();
res.push_str(delim.0);
let mut last = None;
- for child in &self.token_trees {
+ for child in self.token_trees.iter() {
let s = match child {
TokenTree::Leaf(it) => {
let s = match it {
@@ -326,11 +336,11 @@ impl<S> Subtree<S> {
};
match (it, last) {
(Leaf::Ident(_), Some(&TokenTree::Leaf(Leaf::Ident(_)))) => {
- " ".to_string() + &s
+ " ".to_owned() + &s
}
(Leaf::Punct(_), Some(TokenTree::Leaf(Leaf::Punct(punct)))) => {
if punct.spacing == Spacing::Alone {
- " ".to_string() + &s
+ " ".to_owned() + &s
} else {
s
}