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//! Abstract Syntax Tree, layered on top of untyped `SyntaxNode`s
mod generated;
mod traits;
mod tokens;
mod extensions;
mod expr_extensions;
use std::marker::PhantomData;
use crate::{
syntax_node::{SyntaxNode, SyntaxNodeChildren, SyntaxToken},
SmolStr, SyntaxKind,
};
pub use self::{
expr_extensions::{ArrayExprKind, BinOp, ElseBranch, LiteralKind, PrefixOp},
extensions::{FieldKind, PathSegmentKind, SelfParamKind, StructKind},
generated::*,
tokens::*,
traits::*,
};
/// The main trait to go from untyped `SyntaxNode` to a typed ast. The
/// conversion itself has zero runtime cost: ast and syntax nodes have exactly
/// the same representation: a pointer to the tree root and a pointer to the
/// node itself.
pub trait AstNode: Clone {
fn can_cast(kind: SyntaxKind) -> bool;
fn cast(syntax: SyntaxNode) -> Option<Self>
where
Self: Sized;
fn syntax(&self) -> &SyntaxNode;
}
/// Like `AstNode`, but wraps tokens rather than interior nodes.
pub trait AstToken {
fn cast(token: SyntaxToken) -> Option<Self>
where
Self: Sized;
fn syntax(&self) -> &SyntaxToken;
fn text(&self) -> &SmolStr {
self.syntax().text()
}
}
/// An iterator over `SyntaxNode` children of a particular AST type.
#[derive(Debug)]
pub struct AstChildren<N> {
inner: SyntaxNodeChildren,
ph: PhantomData<N>,
}
impl<N> AstChildren<N> {
fn new(parent: &SyntaxNode) -> Self {
AstChildren { inner: parent.children(), ph: PhantomData }
}
}
impl<N: AstNode> Iterator for AstChildren<N> {
type Item = N;
fn next(&mut self) -> Option<N> {
self.inner.by_ref().find_map(N::cast)
}
}
fn child_opt<P: AstNode + ?Sized, C: AstNode>(parent: &P) -> Option<C> {
children(parent).next()
}
fn children<P: AstNode + ?Sized, C: AstNode>(parent: &P) -> AstChildren<C> {
AstChildren::new(parent.syntax())
}
#[test]
fn test_doc_comment_none() {
let file = SourceFile::parse(
r#"
// non-doc
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert!(module.doc_comment_text().is_none());
}
#[test]
fn test_doc_comment_of_items() {
let file = SourceFile::parse(
r#"
//! doc
// non-doc
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert_eq!("doc", module.doc_comment_text().unwrap());
}
#[test]
fn test_doc_comment_preserves_indents() {
let file = SourceFile::parse(
r#"
/// doc1
/// ```
/// fn foo() {
/// // ...
/// }
/// ```
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert_eq!("doc1\n```\nfn foo() {\n // ...\n}\n```", module.doc_comment_text().unwrap());
}
#[test]
fn test_where_predicates() {
fn assert_bound(text: &str, bound: Option<TypeBound>) {
assert_eq!(text, bound.unwrap().syntax().text().to_string());
}
let file = SourceFile::parse(
r#"
fn foo()
where
T: Clone + Copy + Debug + 'static,
'a: 'b + 'c,
Iterator::Item: 'a + Debug,
Iterator::Item: Debug + 'a,
<T as Iterator>::Item: Debug + 'a,
for<'a> F: Fn(&'a str)
{}
"#,
)
.ok()
.unwrap();
let where_clause = file.syntax().descendants().find_map(WhereClause::cast).unwrap();
let mut predicates = where_clause.predicates();
let pred = predicates.next().unwrap();
let mut bounds = pred.type_bound_list().unwrap().bounds();
assert_eq!("T", pred.type_ref().unwrap().syntax().text().to_string());
assert_bound("Clone", bounds.next());
assert_bound("Copy", bounds.next());
assert_bound("Debug", bounds.next());
assert_bound("'static", bounds.next());
let pred = predicates.next().unwrap();
let mut bounds = pred.type_bound_list().unwrap().bounds();
assert_eq!("'a", pred.lifetime_token().unwrap().text());
assert_bound("'b", bounds.next());
assert_bound("'c", bounds.next());
let pred = predicates.next().unwrap();
let mut bounds = pred.type_bound_list().unwrap().bounds();
assert_eq!("Iterator::Item", pred.type_ref().unwrap().syntax().text().to_string());
assert_bound("'a", bounds.next());
let pred = predicates.next().unwrap();
let mut bounds = pred.type_bound_list().unwrap().bounds();
assert_eq!("Iterator::Item", pred.type_ref().unwrap().syntax().text().to_string());
assert_bound("Debug", bounds.next());
assert_bound("'a", bounds.next());
let pred = predicates.next().unwrap();
let mut bounds = pred.type_bound_list().unwrap().bounds();
assert_eq!("<T as Iterator>::Item", pred.type_ref().unwrap().syntax().text().to_string());
assert_bound("Debug", bounds.next());
assert_bound("'a", bounds.next());
let pred = predicates.next().unwrap();
let mut bounds = pred.type_bound_list().unwrap().bounds();
assert_eq!("for<'a> F", pred.type_ref().unwrap().syntax().text().to_string());
assert_bound("Fn(&'a str)", bounds.next());
}
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