use syntax::{ast, AstNode, SyntaxNode};
pub(crate) fn ty(s: &str) -> Result<SyntaxNode, ()> {
- let template = "type T = {};";
- let input = template.replace("{}", s);
- let parse = syntax::SourceFile::parse(&input);
- if !parse.errors().is_empty() {
- return Err(());
- }
- let node = parse.tree().syntax().descendants().find_map(ast::Type::cast).ok_or(())?;
- if node.to_string() != s {
- return Err(());
- }
- Ok(node.syntax().clone_subtree())
+ fragment::<ast::Type>("type T = {};", s)
}
pub(crate) fn item(s: &str) -> Result<SyntaxNode, ()> {
- let template = "{}";
- let input = template.replace("{}", s);
- let parse = syntax::SourceFile::parse(&input);
- if !parse.errors().is_empty() {
- return Err(());
- }
- let node = parse.tree().syntax().descendants().find_map(ast::Item::cast).ok_or(())?;
- if node.to_string() != s {
- return Err(());
- }
- Ok(node.syntax().clone_subtree())
+ fragment::<ast::Item>("{}", s)
}
pub(crate) fn pat(s: &str) -> Result<SyntaxNode, ()> {
- let template = "const _: () = {let {} = ();};";
- let input = template.replace("{}", s);
- let parse = syntax::SourceFile::parse(&input);
- if !parse.errors().is_empty() {
- return Err(());
- }
- let node = parse.tree().syntax().descendants().find_map(ast::Pat::cast).ok_or(())?;
- if node.to_string() != s {
- return Err(());
- }
- Ok(node.syntax().clone_subtree())
+ fragment::<ast::Pat>("const _: () = {let {} = ();};", s)
}
pub(crate) fn expr(s: &str) -> Result<SyntaxNode, ()> {
- let template = "const _: () = {};";
- let input = template.replace("{}", s);
- let parse = syntax::SourceFile::parse(&input);
- if !parse.errors().is_empty() {
- return Err(());
- }
- let node = parse.tree().syntax().descendants().find_map(ast::Expr::cast).ok_or(())?;
- if node.to_string() != s {
- return Err(());
- }
- Ok(node.syntax().clone_subtree())
+ fragment::<ast::Expr>("const _: () = {};", s)
}
pub(crate) fn stmt(s: &str) -> Result<SyntaxNode, ()> {
}
Ok(node.syntax().clone_subtree())
}
+
+fn fragment<T: AstNode>(template: &str, s: &str) -> Result<SyntaxNode, ()> {
+ let s = s.trim();
+ let input = template.replace("{}", s);
+ let parse = syntax::SourceFile::parse(&input);
+ if !parse.errors().is_empty() {
+ return Err(());
+ }
+ let node = parse.tree().syntax().descendants().find_map(T::cast).ok_or(())?;
+ if node.syntax().text() != s {
+ return Err(());
+ }
+ Ok(node.syntax().clone_subtree())
+}