bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/mbe/src/lib.rs')
-rw-r--r--crates/mbe/src/lib.rs68
1 files changed, 63 insertions, 5 deletions
diff --git a/crates/mbe/src/lib.rs b/crates/mbe/src/lib.rs
index ed3200964d..5f0598dfe0 100644
--- a/crates/mbe/src/lib.rs
+++ b/crates/mbe/src/lib.rs
@@ -12,20 +12,17 @@ mod expander;
mod parser;
mod syntax_bridge;
mod to_parser_input;
-mod tt_iter;
#[cfg(test)]
mod benchmark;
use span::{Edition, Span, SyntaxContextId};
use stdx::impl_from;
+use tt::iter::TtIter;
use std::fmt;
-use crate::{
- parser::{MetaTemplate, MetaVarKind, Op},
- tt_iter::TtIter,
-};
+use crate::parser::{MetaTemplate, MetaVarKind, Op};
// FIXME: we probably should re-think `token_tree_to_syntax_node` interfaces
pub use ::parser::TopEntryPoint;
@@ -247,6 +244,10 @@ impl DeclarativeMacro {
self.err.as_deref()
}
+ pub fn num_rules(&self) -> usize {
+ self.rules.len()
+ }
+
pub fn expand(
&self,
tt: &tt::Subtree<Span>,
@@ -361,3 +362,60 @@ impl<T: Default, E> From<Result<T, E>> for ValueResult<T, E> {
result.map_or_else(Self::only_err, Self::ok)
}
}
+
+fn expect_fragment<S: Copy + fmt::Debug>(
+ tt_iter: &mut TtIter<'_, S>,
+ entry_point: ::parser::PrefixEntryPoint,
+ edition: ::parser::Edition,
+) -> ExpandResult<Option<tt::TokenTree<S>>> {
+ use ::parser;
+ let buffer = tt::buffer::TokenBuffer::from_tokens(tt_iter.as_slice());
+ let parser_input = to_parser_input::to_parser_input(&buffer);
+ let tree_traversal = entry_point.parse(&parser_input, edition);
+ let mut cursor = buffer.begin();
+ let mut error = false;
+ for step in tree_traversal.iter() {
+ match step {
+ parser::Step::Token { kind, mut n_input_tokens } => {
+ if kind == ::parser::SyntaxKind::LIFETIME_IDENT {
+ n_input_tokens = 2;
+ }
+ for _ in 0..n_input_tokens {
+ cursor = cursor.bump_subtree();
+ }
+ }
+ parser::Step::FloatSplit { .. } => {
+ // FIXME: We need to split the tree properly here, but mutating the token trees
+ // in the buffer is somewhat tricky to pull off.
+ cursor = cursor.bump_subtree();
+ }
+ parser::Step::Enter { .. } | parser::Step::Exit => (),
+ parser::Step::Error { .. } => error = true,
+ }
+ }
+
+ let err = if error || !cursor.is_root() {
+ Some(ExpandError::binding_error(format!("expected {entry_point:?}")))
+ } else {
+ None
+ };
+
+ let mut curr = buffer.begin();
+ let mut res = vec![];
+
+ while curr != cursor {
+ let Some(token) = curr.token_tree() else { break };
+ res.push(token.cloned());
+ curr = curr.bump();
+ }
+
+ *tt_iter = TtIter::new_iter(tt_iter.as_slice()[res.len()..].iter());
+ let res = match &*res {
+ [] | [_] => res.pop(),
+ [first, ..] => Some(tt::TokenTree::Subtree(tt::Subtree {
+ delimiter: Delimiter::invisible_spanned(first.first_span()),
+ token_trees: res.into_boxed_slice(),
+ })),
+ };
+ ExpandResult { value: res, err }
+}