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.rs39
1 files changed, 31 insertions, 8 deletions
diff --git a/crates/tt/src/lib.rs b/crates/tt/src/lib.rs
index 83681c5339..b87c7ff475 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,
}
@@ -69,12 +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([]) }
+ }
+
+ /// 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() }
}
}
@@ -228,7 +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(" ")?;
}
@@ -303,7 +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 {