bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/syntax/src/ast.rs')
-rw-r--r--crates/syntax/src/ast.rs30
1 files changed, 30 insertions, 0 deletions
diff --git a/crates/syntax/src/ast.rs b/crates/syntax/src/ast.rs
index 10c0457583..385a4e0a3c 100644
--- a/crates/syntax/src/ast.rs
+++ b/crates/syntax/src/ast.rs
@@ -13,6 +13,8 @@ pub mod prec;
use std::marker::PhantomData;
+use itertools::Either;
+
use crate::{
syntax_node::{SyntaxNode, SyntaxNodeChildren, SyntaxToken},
SyntaxKind,
@@ -98,6 +100,34 @@ impl<N: AstNode> Iterator for AstChildren<N> {
}
}
+impl<L, R> AstNode for Either<L, R>
+where
+ L: AstNode,
+ R: AstNode,
+{
+ fn can_cast(kind: SyntaxKind) -> bool
+ where
+ Self: Sized,
+ {
+ L::can_cast(kind) || R::can_cast(kind)
+ }
+
+ fn cast(syntax: SyntaxNode) -> Option<Self>
+ where
+ Self: Sized,
+ {
+ if L::can_cast(syntax.kind()) {
+ L::cast(syntax).map(Either::Left)
+ } else {
+ R::cast(syntax).map(Either::Right)
+ }
+ }
+
+ fn syntax(&self) -> &SyntaxNode {
+ self.as_ref().either(L::syntax, R::syntax)
+ }
+}
+
mod support {
use super::{AstChildren, AstNode, SyntaxKind, SyntaxNode, SyntaxToken};