rust/crates/syntax/src/ast.rs

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//! Abstract Syntax Tree, layered on top of untyped `SyntaxNode`s
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mod generated;
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mod traits;
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mod token_ext;
mod node_ext;
mod expr_ext;
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pub mod edit;
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pub mod make;
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use std::marker::PhantomData;
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use crate::{
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syntax_node::{SyntaxNode, SyntaxNodeChildren, SyntaxToken},
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SmolStr, SyntaxKind,
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};
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pub use self::{
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expr_ext::{ArrayExprKind, BinOp, Effect, ElseBranch, LiteralKind, PrefixOp, RangeOp},
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generated::*,
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node_ext::{
AttrKind, FieldKind, NameOrNameRef, PathSegmentKind, SelfParamKind, SlicePatComponents,
StructKind, TypeBoundKind, VisibilityKind,
},
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token_ext::*,
traits::*,
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};
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/// 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.
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pub trait AstNode {
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fn can_cast(kind: SyntaxKind) -> bool
where
Self: Sized;
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fn cast(syntax: SyntaxNode) -> Option<Self>
where
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Self: Sized;
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fn syntax(&self) -> &SyntaxNode;
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}
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/// Like `AstNode`, but wraps tokens rather than interior nodes.
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pub trait AstToken {
fn can_cast(token: SyntaxKind) -> bool
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where
Self: Sized;
fn cast(syntax: SyntaxToken) -> Option<Self>
where
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Self: Sized;
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fn syntax(&self) -> &SyntaxToken;
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fn text(&self) -> &SmolStr {
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self.syntax().text()
}
}
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/// An iterator over `SyntaxNode` children of a particular AST type.
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#[derive(Debug, Clone)]
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pub struct AstChildren<N> {
inner: SyntaxNodeChildren,
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ph: PhantomData<N>,
}
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impl<N> AstChildren<N> {
fn new(parent: &SyntaxNode) -> Self {
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AstChildren { inner: parent.children(), ph: PhantomData }
}
}
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impl<N: AstNode> Iterator for AstChildren<N> {
type Item = N;
fn next(&mut self) -> Option<N> {
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self.inner.find_map(N::cast)
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}
}
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mod support {
use super::{AstChildren, AstNode, SyntaxKind, SyntaxNode, SyntaxToken};
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pub(super) fn child<N: AstNode>(parent: &SyntaxNode) -> Option<N> {
parent.children().find_map(N::cast)
}
pub(super) fn children<N: AstNode>(parent: &SyntaxNode) -> AstChildren<N> {
AstChildren::new(parent)
}
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pub(super) fn token(parent: &SyntaxNode, kind: SyntaxKind) -> Option<SyntaxToken> {
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parent.children_with_tokens().filter_map(|it| it.into_token()).find(|it| it.kind() == kind)
}
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}
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#[test]
fn assert_ast_is_object_safe() {
fn _f(_: &dyn AstNode, _: &dyn NameOwner) {}
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}
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#[test]
fn test_doc_comment_none() {
let file = SourceFile::parse(
r#"
// non-doc
mod foo {}
"#,
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)
.ok()
.unwrap();
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let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert!(module.doc_comment_text().is_none());
}
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#[test]
fn test_doc_comment_of_items() {
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let file = SourceFile::parse(
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r#"
//! doc
// non-doc
mod foo {}
"#,
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)
.ok()
.unwrap();
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let module = file.syntax().descendants().find_map(Module::cast).unwrap();
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assert_eq!("doc", module.doc_comment_text().unwrap());
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}
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#[test]
fn test_doc_comment_of_statics() {
let file = SourceFile::parse(
r#"
/// Number of levels
static LEVELS: i32 = 0;
"#,
)
.ok()
.unwrap();
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let st = file.syntax().descendants().find_map(Static::cast).unwrap();
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assert_eq!("Number of levels", st.doc_comment_text().unwrap());
}
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#[test]
fn test_doc_comment_preserves_indents() {
let file = SourceFile::parse(
r#"
/// doc1
/// ```
/// fn foo() {
/// // ...
/// }
/// ```
mod foo {}
"#,
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)
.ok()
.unwrap();
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let module = file.syntax().descendants().find_map(Module::cast).unwrap();
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assert_eq!("doc1\n```\nfn foo() {\n // ...\n}\n```", module.doc_comment_text().unwrap());
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}
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#[test]
fn test_doc_comment_preserves_newlines() {
let file = SourceFile::parse(
r#"
/// this
/// is
/// mod
/// foo
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert_eq!("this\nis\nmod\nfoo", module.doc_comment_text().unwrap());
}
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#[test]
fn test_doc_comment_single_line_block_strips_suffix() {
let file = SourceFile::parse(
r#"
/** this is mod foo*/
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert_eq!("this is mod foo", module.doc_comment_text().unwrap());
}
#[test]
fn test_doc_comment_single_line_block_strips_suffix_whitespace() {
let file = SourceFile::parse(
r#"
/** this is mod foo */
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert_eq!("this is mod foo ", module.doc_comment_text().unwrap());
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}
#[test]
fn test_doc_comment_multi_line_block_strips_suffix() {
let file = SourceFile::parse(
r#"
/**
this
is
mod foo
*/
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert_eq!(
" this\n is\n mod foo\n ",
module.doc_comment_text().unwrap()
);
}
#[test]
fn test_comments_preserve_trailing_whitespace() {
let file = SourceFile::parse(
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"\n/// Representation of a Realm. \n/// In the specification these are called Realm Records.\nstruct Realm {}",
)
.ok()
.unwrap();
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let def = file.syntax().descendants().find_map(Struct::cast).unwrap();
assert_eq!(
"Representation of a Realm. \nIn the specification these are called Realm Records.",
def.doc_comment_text().unwrap()
);
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}
#[test]
fn test_four_slash_line_comment() {
let file = SourceFile::parse(
r#"
//// too many slashes to be a doc comment
/// doc comment
mod foo {}
"#,
)
.ok()
.unwrap();
let module = file.syntax().descendants().find_map(Module::cast).unwrap();
assert_eq!("doc comment", module.doc_comment_text().unwrap());
}
#[test]
fn test_where_predicates() {
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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)
{}
"#,
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)
.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!(pred.for_token().is_none());
assert!(pred.generic_param_list().is_none());
assert_eq!("T", pred.ty().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.ty().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.ty().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.ty().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!(pred.for_token().is_some());
assert_eq!("<'a>", pred.generic_param_list().unwrap().syntax().text().to_string());
assert_eq!("F", pred.ty().unwrap().syntax().text().to_string());
assert_bound("Fn(&'a str)", bounds.next());
}