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-rw-r--r--crates/syntax/src/ast.rs331
1 files changed, 331 insertions, 0 deletions
diff --git a/crates/syntax/src/ast.rs b/crates/syntax/src/ast.rs
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1//! Abstract Syntax Tree, layered on top of untyped `SyntaxNode`s
2
3mod generated;
4mod traits;
5mod token_ext;
6mod node_ext;
7mod expr_ext;
8pub mod edit;
9pub mod make;
10
11use std::marker::PhantomData;
12
13use crate::{
14 syntax_node::{SyntaxNode, SyntaxNodeChildren, SyntaxToken},
15 SmolStr, SyntaxKind,
16};
17
18pub use self::{
19 expr_ext::{ArrayExprKind, BinOp, Effect, ElseBranch, LiteralKind, PrefixOp, RangeOp},
20 generated::*,
21 node_ext::{
22 AttrKind, FieldKind, NameOrNameRef, PathSegmentKind, SelfParamKind, SlicePatComponents,
23 StructKind, TypeBoundKind, VisibilityKind,
24 },
25 token_ext::*,
26 traits::*,
27};
28
29/// The main trait to go from untyped `SyntaxNode` to a typed ast. The
30/// conversion itself has zero runtime cost: ast and syntax nodes have exactly
31/// the same representation: a pointer to the tree root and a pointer to the
32/// node itself.
33pub trait AstNode {
34 fn can_cast(kind: SyntaxKind) -> bool
35 where
36 Self: Sized;
37
38 fn cast(syntax: SyntaxNode) -> Option<Self>
39 where
40 Self: Sized;
41
42 fn syntax(&self) -> &SyntaxNode;
43}
44
45/// Like `AstNode`, but wraps tokens rather than interior nodes.
46pub trait AstToken {
47 fn can_cast(token: SyntaxKind) -> bool
48 where
49 Self: Sized;
50
51 fn cast(syntax: SyntaxToken) -> Option<Self>
52 where
53 Self: Sized;
54
55 fn syntax(&self) -> &SyntaxToken;
56
57 fn text(&self) -> &SmolStr {
58 self.syntax().text()
59 }
60}
61
62/// An iterator over `SyntaxNode` children of a particular AST type.
63#[derive(Debug, Clone)]
64pub struct AstChildren<N> {
65 inner: SyntaxNodeChildren,
66 ph: PhantomData<N>,
67}
68
69impl<N> AstChildren<N> {
70 fn new(parent: &SyntaxNode) -> Self {
71 AstChildren { inner: parent.children(), ph: PhantomData }
72 }
73}
74
75impl<N: AstNode> Iterator for AstChildren<N> {
76 type Item = N;
77 fn next(&mut self) -> Option<N> {
78 self.inner.find_map(N::cast)
79 }
80}
81
82mod support {
83 use super::{AstChildren, AstNode, SyntaxKind, SyntaxNode, SyntaxToken};
84
85 pub(super) fn child<N: AstNode>(parent: &SyntaxNode) -> Option<N> {
86 parent.children().find_map(N::cast)
87 }
88
89 pub(super) fn children<N: AstNode>(parent: &SyntaxNode) -> AstChildren<N> {
90 AstChildren::new(parent)
91 }
92
93 pub(super) fn token(parent: &SyntaxNode, kind: SyntaxKind) -> Option<SyntaxToken> {
94 parent.children_with_tokens().filter_map(|it| it.into_token()).find(|it| it.kind() == kind)
95 }
96}
97
98#[test]
99fn assert_ast_is_object_safe() {
100 fn _f(_: &dyn AstNode, _: &dyn NameOwner) {}
101}
102
103#[test]
104fn test_doc_comment_none() {
105 let file = SourceFile::parse(
106 r#"
107 // non-doc
108 mod foo {}
109 "#,
110 )
111 .ok()
112 .unwrap();
113 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
114 assert!(module.doc_comment_text().is_none());
115}
116
117#[test]
118fn test_doc_comment_of_items() {
119 let file = SourceFile::parse(
120 r#"
121 //! doc
122 // non-doc
123 mod foo {}
124 "#,
125 )
126 .ok()
127 .unwrap();
128 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
129 assert_eq!("doc", module.doc_comment_text().unwrap());
130}
131
132#[test]
133fn test_doc_comment_of_statics() {
134 let file = SourceFile::parse(
135 r#"
136 /// Number of levels
137 static LEVELS: i32 = 0;
138 "#,
139 )
140 .ok()
141 .unwrap();
142 let st = file.syntax().descendants().find_map(Static::cast).unwrap();
143 assert_eq!("Number of levels", st.doc_comment_text().unwrap());
144}
145
146#[test]
147fn test_doc_comment_preserves_indents() {
148 let file = SourceFile::parse(
149 r#"
150 /// doc1
151 /// ```
152 /// fn foo() {
153 /// // ...
154 /// }
155 /// ```
156 mod foo {}
157 "#,
158 )
159 .ok()
160 .unwrap();
161 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
162 assert_eq!("doc1\n```\nfn foo() {\n // ...\n}\n```", module.doc_comment_text().unwrap());
163}
164
165#[test]
166fn test_doc_comment_preserves_newlines() {
167 let file = SourceFile::parse(
168 r#"
169 /// this
170 /// is
171 /// mod
172 /// foo
173 mod foo {}
174 "#,
175 )
176 .ok()
177 .unwrap();
178 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
179 assert_eq!("this\nis\nmod\nfoo", module.doc_comment_text().unwrap());
180}
181
182#[test]
183fn test_doc_comment_single_line_block_strips_suffix() {
184 let file = SourceFile::parse(
185 r#"
186 /** this is mod foo*/
187 mod foo {}
188 "#,
189 )
190 .ok()
191 .unwrap();
192 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
193 assert_eq!("this is mod foo", module.doc_comment_text().unwrap());
194}
195
196#[test]
197fn test_doc_comment_single_line_block_strips_suffix_whitespace() {
198 let file = SourceFile::parse(
199 r#"
200 /** this is mod foo */
201 mod foo {}
202 "#,
203 )
204 .ok()
205 .unwrap();
206 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
207 assert_eq!("this is mod foo ", module.doc_comment_text().unwrap());
208}
209
210#[test]
211fn test_doc_comment_multi_line_block_strips_suffix() {
212 let file = SourceFile::parse(
213 r#"
214 /**
215 this
216 is
217 mod foo
218 */
219 mod foo {}
220 "#,
221 )
222 .ok()
223 .unwrap();
224 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
225 assert_eq!(
226 " this\n is\n mod foo\n ",
227 module.doc_comment_text().unwrap()
228 );
229}
230
231#[test]
232fn test_comments_preserve_trailing_whitespace() {
233 let file = SourceFile::parse(
234 "\n/// Representation of a Realm. \n/// In the specification these are called Realm Records.\nstruct Realm {}",
235 )
236 .ok()
237 .unwrap();
238 let def = file.syntax().descendants().find_map(Struct::cast).unwrap();
239 assert_eq!(
240 "Representation of a Realm. \nIn the specification these are called Realm Records.",
241 def.doc_comment_text().unwrap()
242 );
243}
244
245#[test]
246fn test_four_slash_line_comment() {
247 let file = SourceFile::parse(
248 r#"
249 //// too many slashes to be a doc comment
250 /// doc comment
251 mod foo {}
252 "#,
253 )
254 .ok()
255 .unwrap();
256 let module = file.syntax().descendants().find_map(Module::cast).unwrap();
257 assert_eq!("doc comment", module.doc_comment_text().unwrap());
258}
259
260#[test]
261fn test_where_predicates() {
262 fn assert_bound(text: &str, bound: Option<TypeBound>) {
263 assert_eq!(text, bound.unwrap().syntax().text().to_string());
264 }
265
266 let file = SourceFile::parse(
267 r#"
268fn foo()
269where
270 T: Clone + Copy + Debug + 'static,
271 'a: 'b + 'c,
272 Iterator::Item: 'a + Debug,
273 Iterator::Item: Debug + 'a,
274 <T as Iterator>::Item: Debug + 'a,
275 for<'a> F: Fn(&'a str)
276{}
277 "#,
278 )
279 .ok()
280 .unwrap();
281 let where_clause = file.syntax().descendants().find_map(WhereClause::cast).unwrap();
282
283 let mut predicates = where_clause.predicates();
284
285 let pred = predicates.next().unwrap();
286 let mut bounds = pred.type_bound_list().unwrap().bounds();
287
288 assert!(pred.for_token().is_none());
289 assert!(pred.generic_param_list().is_none());
290 assert_eq!("T", pred.ty().unwrap().syntax().text().to_string());
291 assert_bound("Clone", bounds.next());
292 assert_bound("Copy", bounds.next());
293 assert_bound("Debug", bounds.next());
294 assert_bound("'static", bounds.next());
295
296 let pred = predicates.next().unwrap();
297 let mut bounds = pred.type_bound_list().unwrap().bounds();
298
299 assert_eq!("'a", pred.lifetime_token().unwrap().text());
300
301 assert_bound("'b", bounds.next());
302 assert_bound("'c", bounds.next());
303
304 let pred = predicates.next().unwrap();
305 let mut bounds = pred.type_bound_list().unwrap().bounds();
306
307 assert_eq!("Iterator::Item", pred.ty().unwrap().syntax().text().to_string());
308 assert_bound("'a", bounds.next());
309
310 let pred = predicates.next().unwrap();
311 let mut bounds = pred.type_bound_list().unwrap().bounds();
312
313 assert_eq!("Iterator::Item", pred.ty().unwrap().syntax().text().to_string());
314 assert_bound("Debug", bounds.next());
315 assert_bound("'a", bounds.next());
316
317 let pred = predicates.next().unwrap();
318 let mut bounds = pred.type_bound_list().unwrap().bounds();
319
320 assert_eq!("<T as Iterator>::Item", pred.ty().unwrap().syntax().text().to_string());
321 assert_bound("Debug", bounds.next());
322 assert_bound("'a", bounds.next());
323
324 let pred = predicates.next().unwrap();
325 let mut bounds = pred.type_bound_list().unwrap().bounds();
326
327 assert!(pred.for_token().is_some());
328 assert_eq!("<'a>", pred.generic_param_list().unwrap().syntax().text().to_string());
329 assert_eq!("F", pred.ty().unwrap().syntax().text().to_string());
330 assert_bound("Fn(&'a str)", bounds.next());
331}