diff options
Diffstat (limited to 'crates/ra_assists/src/handlers/introduce_variable.rs')
-rw-r--r-- | crates/ra_assists/src/handlers/introduce_variable.rs | 529 |
1 files changed, 529 insertions, 0 deletions
diff --git a/crates/ra_assists/src/handlers/introduce_variable.rs b/crates/ra_assists/src/handlers/introduce_variable.rs new file mode 100644 index 000000000..7312ce687 --- /dev/null +++ b/crates/ra_assists/src/handlers/introduce_variable.rs | |||
@@ -0,0 +1,529 @@ | |||
1 | use format_buf::format; | ||
2 | use ra_syntax::{ | ||
3 | ast::{self, AstNode}, | ||
4 | SyntaxKind::{ | ||
5 | BLOCK_EXPR, BREAK_EXPR, COMMENT, LAMBDA_EXPR, LOOP_EXPR, MATCH_ARM, PATH_EXPR, RETURN_EXPR, | ||
6 | WHITESPACE, | ||
7 | }, | ||
8 | SyntaxNode, TextUnit, | ||
9 | }; | ||
10 | use test_utils::tested_by; | ||
11 | |||
12 | use crate::{Assist, AssistCtx, AssistId}; | ||
13 | |||
14 | // Assist: introduce_variable | ||
15 | // | ||
16 | // Extracts subexpression into a variable. | ||
17 | // | ||
18 | // ``` | ||
19 | // fn main() { | ||
20 | // <|>(1 + 2)<|> * 4; | ||
21 | // } | ||
22 | // ``` | ||
23 | // -> | ||
24 | // ``` | ||
25 | // fn main() { | ||
26 | // let var_name = (1 + 2); | ||
27 | // var_name * 4; | ||
28 | // } | ||
29 | // ``` | ||
30 | pub(crate) fn introduce_variable(ctx: AssistCtx) -> Option<Assist> { | ||
31 | if ctx.frange.range.is_empty() { | ||
32 | return None; | ||
33 | } | ||
34 | let node = ctx.covering_element(); | ||
35 | if node.kind() == COMMENT { | ||
36 | tested_by!(introduce_var_in_comment_is_not_applicable); | ||
37 | return None; | ||
38 | } | ||
39 | let expr = node.ancestors().find_map(valid_target_expr)?; | ||
40 | let (anchor_stmt, wrap_in_block) = anchor_stmt(expr.clone())?; | ||
41 | let indent = anchor_stmt.prev_sibling_or_token()?.as_token()?.clone(); | ||
42 | if indent.kind() != WHITESPACE { | ||
43 | return None; | ||
44 | } | ||
45 | ctx.add_assist(AssistId("introduce_variable"), "Extract into variable", move |edit| { | ||
46 | let mut buf = String::new(); | ||
47 | |||
48 | let cursor_offset = if wrap_in_block { | ||
49 | buf.push_str("{ let var_name = "); | ||
50 | TextUnit::of_str("{ let ") | ||
51 | } else { | ||
52 | buf.push_str("let var_name = "); | ||
53 | TextUnit::of_str("let ") | ||
54 | }; | ||
55 | format!(buf, "{}", expr.syntax()); | ||
56 | let full_stmt = ast::ExprStmt::cast(anchor_stmt.clone()); | ||
57 | let is_full_stmt = if let Some(expr_stmt) = &full_stmt { | ||
58 | Some(expr.syntax().clone()) == expr_stmt.expr().map(|e| e.syntax().clone()) | ||
59 | } else { | ||
60 | false | ||
61 | }; | ||
62 | if is_full_stmt { | ||
63 | tested_by!(test_introduce_var_expr_stmt); | ||
64 | if !full_stmt.unwrap().has_semi() { | ||
65 | buf.push_str(";"); | ||
66 | } | ||
67 | edit.replace(expr.syntax().text_range(), buf); | ||
68 | } else { | ||
69 | buf.push_str(";"); | ||
70 | |||
71 | // We want to maintain the indent level, | ||
72 | // but we do not want to duplicate possible | ||
73 | // extra newlines in the indent block | ||
74 | let text = indent.text(); | ||
75 | if text.starts_with('\n') { | ||
76 | buf.push_str("\n"); | ||
77 | buf.push_str(text.trim_start_matches('\n')); | ||
78 | } else { | ||
79 | buf.push_str(text); | ||
80 | } | ||
81 | |||
82 | edit.target(expr.syntax().text_range()); | ||
83 | edit.replace(expr.syntax().text_range(), "var_name".to_string()); | ||
84 | edit.insert(anchor_stmt.text_range().start(), buf); | ||
85 | if wrap_in_block { | ||
86 | edit.insert(anchor_stmt.text_range().end(), " }"); | ||
87 | } | ||
88 | } | ||
89 | edit.set_cursor(anchor_stmt.text_range().start() + cursor_offset); | ||
90 | }) | ||
91 | } | ||
92 | |||
93 | /// Check whether the node is a valid expression which can be extracted to a variable. | ||
94 | /// In general that's true for any expression, but in some cases that would produce invalid code. | ||
95 | fn valid_target_expr(node: SyntaxNode) -> Option<ast::Expr> { | ||
96 | match node.kind() { | ||
97 | PATH_EXPR | LOOP_EXPR => None, | ||
98 | BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()), | ||
99 | RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()), | ||
100 | BLOCK_EXPR => { | ||
101 | ast::BlockExpr::cast(node).filter(|it| it.is_standalone()).map(ast::Expr::from) | ||
102 | } | ||
103 | _ => ast::Expr::cast(node), | ||
104 | } | ||
105 | } | ||
106 | |||
107 | /// Returns the syntax node which will follow the freshly introduced var | ||
108 | /// and a boolean indicating whether we have to wrap it within a { } block | ||
109 | /// to produce correct code. | ||
110 | /// It can be a statement, the last in a block expression or a wanna be block | ||
111 | /// expression like a lambda or match arm. | ||
112 | fn anchor_stmt(expr: ast::Expr) -> Option<(SyntaxNode, bool)> { | ||
113 | expr.syntax().ancestors().find_map(|node| { | ||
114 | if let Some(expr) = node.parent().and_then(ast::Block::cast).and_then(|it| it.expr()) { | ||
115 | if expr.syntax() == &node { | ||
116 | tested_by!(test_introduce_var_last_expr); | ||
117 | return Some((node, false)); | ||
118 | } | ||
119 | } | ||
120 | |||
121 | if let Some(parent) = node.parent() { | ||
122 | if parent.kind() == MATCH_ARM || parent.kind() == LAMBDA_EXPR { | ||
123 | return Some((node, true)); | ||
124 | } | ||
125 | } | ||
126 | |||
127 | if ast::Stmt::cast(node.clone()).is_some() { | ||
128 | return Some((node, false)); | ||
129 | } | ||
130 | |||
131 | None | ||
132 | }) | ||
133 | } | ||
134 | |||
135 | #[cfg(test)] | ||
136 | mod tests { | ||
137 | use test_utils::covers; | ||
138 | |||
139 | use crate::helpers::{ | ||
140 | check_assist_range, check_assist_range_not_applicable, check_assist_range_target, | ||
141 | }; | ||
142 | |||
143 | use super::*; | ||
144 | |||
145 | #[test] | ||
146 | fn test_introduce_var_simple() { | ||
147 | check_assist_range( | ||
148 | introduce_variable, | ||
149 | " | ||
150 | fn foo() { | ||
151 | foo(<|>1 + 1<|>); | ||
152 | }", | ||
153 | " | ||
154 | fn foo() { | ||
155 | let <|>var_name = 1 + 1; | ||
156 | foo(var_name); | ||
157 | }", | ||
158 | ); | ||
159 | } | ||
160 | |||
161 | #[test] | ||
162 | fn introduce_var_in_comment_is_not_applicable() { | ||
163 | covers!(introduce_var_in_comment_is_not_applicable); | ||
164 | check_assist_range_not_applicable( | ||
165 | introduce_variable, | ||
166 | "fn main() { 1 + /* <|>comment<|> */ 1; }", | ||
167 | ); | ||
168 | } | ||
169 | |||
170 | #[test] | ||
171 | fn test_introduce_var_expr_stmt() { | ||
172 | covers!(test_introduce_var_expr_stmt); | ||
173 | check_assist_range( | ||
174 | introduce_variable, | ||
175 | " | ||
176 | fn foo() { | ||
177 | <|>1 + 1<|>; | ||
178 | }", | ||
179 | " | ||
180 | fn foo() { | ||
181 | let <|>var_name = 1 + 1; | ||
182 | }", | ||
183 | ); | ||
184 | check_assist_range( | ||
185 | introduce_variable, | ||
186 | " | ||
187 | fn foo() { | ||
188 | <|>{ let x = 0; x }<|> | ||
189 | something_else(); | ||
190 | }", | ||
191 | " | ||
192 | fn foo() { | ||
193 | let <|>var_name = { let x = 0; x }; | ||
194 | something_else(); | ||
195 | }", | ||
196 | ); | ||
197 | } | ||
198 | |||
199 | #[test] | ||
200 | fn test_introduce_var_part_of_expr_stmt() { | ||
201 | check_assist_range( | ||
202 | introduce_variable, | ||
203 | " | ||
204 | fn foo() { | ||
205 | <|>1<|> + 1; | ||
206 | }", | ||
207 | " | ||
208 | fn foo() { | ||
209 | let <|>var_name = 1; | ||
210 | var_name + 1; | ||
211 | }", | ||
212 | ); | ||
213 | } | ||
214 | |||
215 | #[test] | ||
216 | fn test_introduce_var_last_expr() { | ||
217 | covers!(test_introduce_var_last_expr); | ||
218 | check_assist_range( | ||
219 | introduce_variable, | ||
220 | " | ||
221 | fn foo() { | ||
222 | bar(<|>1 + 1<|>) | ||
223 | }", | ||
224 | " | ||
225 | fn foo() { | ||
226 | let <|>var_name = 1 + 1; | ||
227 | bar(var_name) | ||
228 | }", | ||
229 | ); | ||
230 | check_assist_range( | ||
231 | introduce_variable, | ||
232 | " | ||
233 | fn foo() { | ||
234 | <|>bar(1 + 1)<|> | ||
235 | }", | ||
236 | " | ||
237 | fn foo() { | ||
238 | let <|>var_name = bar(1 + 1); | ||
239 | var_name | ||
240 | }", | ||
241 | ) | ||
242 | } | ||
243 | |||
244 | #[test] | ||
245 | fn test_introduce_var_in_match_arm_no_block() { | ||
246 | check_assist_range( | ||
247 | introduce_variable, | ||
248 | " | ||
249 | fn main() { | ||
250 | let x = true; | ||
251 | let tuple = match x { | ||
252 | true => (<|>2 + 2<|>, true) | ||
253 | _ => (0, false) | ||
254 | }; | ||
255 | } | ||
256 | ", | ||
257 | " | ||
258 | fn main() { | ||
259 | let x = true; | ||
260 | let tuple = match x { | ||
261 | true => { let <|>var_name = 2 + 2; (var_name, true) } | ||
262 | _ => (0, false) | ||
263 | }; | ||
264 | } | ||
265 | ", | ||
266 | ); | ||
267 | } | ||
268 | |||
269 | #[test] | ||
270 | fn test_introduce_var_in_match_arm_with_block() { | ||
271 | check_assist_range( | ||
272 | introduce_variable, | ||
273 | " | ||
274 | fn main() { | ||
275 | let x = true; | ||
276 | let tuple = match x { | ||
277 | true => { | ||
278 | let y = 1; | ||
279 | (<|>2 + y<|>, true) | ||
280 | } | ||
281 | _ => (0, false) | ||
282 | }; | ||
283 | } | ||
284 | ", | ||
285 | " | ||
286 | fn main() { | ||
287 | let x = true; | ||
288 | let tuple = match x { | ||
289 | true => { | ||
290 | let y = 1; | ||
291 | let <|>var_name = 2 + y; | ||
292 | (var_name, true) | ||
293 | } | ||
294 | _ => (0, false) | ||
295 | }; | ||
296 | } | ||
297 | ", | ||
298 | ); | ||
299 | } | ||
300 | |||
301 | #[test] | ||
302 | fn test_introduce_var_in_closure_no_block() { | ||
303 | check_assist_range( | ||
304 | introduce_variable, | ||
305 | " | ||
306 | fn main() { | ||
307 | let lambda = |x: u32| <|>x * 2<|>; | ||
308 | } | ||
309 | ", | ||
310 | " | ||
311 | fn main() { | ||
312 | let lambda = |x: u32| { let <|>var_name = x * 2; var_name }; | ||
313 | } | ||
314 | ", | ||
315 | ); | ||
316 | } | ||
317 | |||
318 | #[test] | ||
319 | fn test_introduce_var_in_closure_with_block() { | ||
320 | check_assist_range( | ||
321 | introduce_variable, | ||
322 | " | ||
323 | fn main() { | ||
324 | let lambda = |x: u32| { <|>x * 2<|> }; | ||
325 | } | ||
326 | ", | ||
327 | " | ||
328 | fn main() { | ||
329 | let lambda = |x: u32| { let <|>var_name = x * 2; var_name }; | ||
330 | } | ||
331 | ", | ||
332 | ); | ||
333 | } | ||
334 | |||
335 | #[test] | ||
336 | fn test_introduce_var_path_simple() { | ||
337 | check_assist_range( | ||
338 | introduce_variable, | ||
339 | " | ||
340 | fn main() { | ||
341 | let o = <|>Some(true)<|>; | ||
342 | } | ||
343 | ", | ||
344 | " | ||
345 | fn main() { | ||
346 | let <|>var_name = Some(true); | ||
347 | let o = var_name; | ||
348 | } | ||
349 | ", | ||
350 | ); | ||
351 | } | ||
352 | |||
353 | #[test] | ||
354 | fn test_introduce_var_path_method() { | ||
355 | check_assist_range( | ||
356 | introduce_variable, | ||
357 | " | ||
358 | fn main() { | ||
359 | let v = <|>bar.foo()<|>; | ||
360 | } | ||
361 | ", | ||
362 | " | ||
363 | fn main() { | ||
364 | let <|>var_name = bar.foo(); | ||
365 | let v = var_name; | ||
366 | } | ||
367 | ", | ||
368 | ); | ||
369 | } | ||
370 | |||
371 | #[test] | ||
372 | fn test_introduce_var_return() { | ||
373 | check_assist_range( | ||
374 | introduce_variable, | ||
375 | " | ||
376 | fn foo() -> u32 { | ||
377 | <|>return 2 + 2<|>; | ||
378 | } | ||
379 | ", | ||
380 | " | ||
381 | fn foo() -> u32 { | ||
382 | let <|>var_name = 2 + 2; | ||
383 | return var_name; | ||
384 | } | ||
385 | ", | ||
386 | ); | ||
387 | } | ||
388 | |||
389 | #[test] | ||
390 | fn test_introduce_var_does_not_add_extra_whitespace() { | ||
391 | check_assist_range( | ||
392 | introduce_variable, | ||
393 | " | ||
394 | fn foo() -> u32 { | ||
395 | |||
396 | |||
397 | <|>return 2 + 2<|>; | ||
398 | } | ||
399 | ", | ||
400 | " | ||
401 | fn foo() -> u32 { | ||
402 | |||
403 | |||
404 | let <|>var_name = 2 + 2; | ||
405 | return var_name; | ||
406 | } | ||
407 | ", | ||
408 | ); | ||
409 | |||
410 | check_assist_range( | ||
411 | introduce_variable, | ||
412 | " | ||
413 | fn foo() -> u32 { | ||
414 | |||
415 | <|>return 2 + 2<|>; | ||
416 | } | ||
417 | ", | ||
418 | " | ||
419 | fn foo() -> u32 { | ||
420 | |||
421 | let <|>var_name = 2 + 2; | ||
422 | return var_name; | ||
423 | } | ||
424 | ", | ||
425 | ); | ||
426 | |||
427 | check_assist_range( | ||
428 | introduce_variable, | ||
429 | " | ||
430 | fn foo() -> u32 { | ||
431 | let foo = 1; | ||
432 | |||
433 | // bar | ||
434 | |||
435 | |||
436 | <|>return 2 + 2<|>; | ||
437 | } | ||
438 | ", | ||
439 | " | ||
440 | fn foo() -> u32 { | ||
441 | let foo = 1; | ||
442 | |||
443 | // bar | ||
444 | |||
445 | |||
446 | let <|>var_name = 2 + 2; | ||
447 | return var_name; | ||
448 | } | ||
449 | ", | ||
450 | ); | ||
451 | } | ||
452 | |||
453 | #[test] | ||
454 | fn test_introduce_var_break() { | ||
455 | check_assist_range( | ||
456 | introduce_variable, | ||
457 | " | ||
458 | fn main() { | ||
459 | let result = loop { | ||
460 | <|>break 2 + 2<|>; | ||
461 | }; | ||
462 | } | ||
463 | ", | ||
464 | " | ||
465 | fn main() { | ||
466 | let result = loop { | ||
467 | let <|>var_name = 2 + 2; | ||
468 | break var_name; | ||
469 | }; | ||
470 | } | ||
471 | ", | ||
472 | ); | ||
473 | } | ||
474 | |||
475 | #[test] | ||
476 | fn test_introduce_var_for_cast() { | ||
477 | check_assist_range( | ||
478 | introduce_variable, | ||
479 | " | ||
480 | fn main() { | ||
481 | let v = <|>0f32 as u32<|>; | ||
482 | } | ||
483 | ", | ||
484 | " | ||
485 | fn main() { | ||
486 | let <|>var_name = 0f32 as u32; | ||
487 | let v = var_name; | ||
488 | } | ||
489 | ", | ||
490 | ); | ||
491 | } | ||
492 | |||
493 | #[test] | ||
494 | fn test_introduce_var_for_return_not_applicable() { | ||
495 | check_assist_range_not_applicable(introduce_variable, "fn foo() { <|>return<|>; } "); | ||
496 | } | ||
497 | |||
498 | #[test] | ||
499 | fn test_introduce_var_for_break_not_applicable() { | ||
500 | check_assist_range_not_applicable( | ||
501 | introduce_variable, | ||
502 | "fn main() { loop { <|>break<|>; }; }", | ||
503 | ); | ||
504 | } | ||
505 | |||
506 | // FIXME: This is not quite correct, but good enough(tm) for the sorting heuristic | ||
507 | #[test] | ||
508 | fn introduce_var_target() { | ||
509 | check_assist_range_target( | ||
510 | introduce_variable, | ||
511 | "fn foo() -> u32 { <|>return 2 + 2<|>; }", | ||
512 | "2 + 2", | ||
513 | ); | ||
514 | |||
515 | check_assist_range_target( | ||
516 | introduce_variable, | ||
517 | " | ||
518 | fn main() { | ||
519 | let x = true; | ||
520 | let tuple = match x { | ||
521 | true => (<|>2 + 2<|>, true) | ||
522 | _ => (0, false) | ||
523 | }; | ||
524 | } | ||
525 | ", | ||
526 | "2 + 2", | ||
527 | ); | ||
528 | } | ||
529 | } | ||