(&self, start: TextSize)
| 288 | } |
| 289 | |
| 290 | fn node_range(&self, start: TextSize) -> TextRange { |
| 291 | // It's possible during error recovery that the parsing didn't consume any tokens. In that |
| 292 | // case, `last_token_end` still points to the end of the previous token but `start` is the |
| 293 | // start of the current token. Calling `TextRange::new(start, self.last_token_end)` would |
| 294 | // panic in that case because `start > end`. This path "detects" this case and creates an |
| 295 | // empty range instead. |
| 296 | // |
| 297 | // The reason it's `<=` instead of just `==` is because there could be whitespaces between |
| 298 | // the two tokens. For example: |
| 299 | // |
| 300 | // ```python |
| 301 | // # last token end |
| 302 | // # | current token (newline) start |
| 303 | // # v v |
| 304 | // def foo \n |
| 305 | // # ^ |
| 306 | // # assume there's trailing whitespace here |
| 307 | // ``` |
| 308 | // |
| 309 | // Or, there could tokens that are considered "trivia" and thus aren't emitted by the token |
| 310 | // source. These are comments and non-logical newlines. For example: |
| 311 | // |
| 312 | // ```python |
| 313 | // # last token end |
| 314 | // # v |
| 315 | // def foo # comment\n |
| 316 | // # ^ current token (newline) start |
| 317 | // ``` |
| 318 | // |
| 319 | // In either of the above cases, there's a "gap" between the end of the last token and start |
| 320 | // of the current token. |
| 321 | if self.prev_token_end <= start { |
| 322 | // We need to create an empty range at the last token end instead of the start because |
| 323 | // otherwise this node range will fall outside the range of it's parent node. Taking |
| 324 | // the above example: |
| 325 | // |
| 326 | // ```python |
| 327 | // if True: |
| 328 | // # function start |
| 329 | // # | function end |
| 330 | // # v v |
| 331 | // def foo # comment |
| 332 | // # ^ current token start |
| 333 | // ``` |
| 334 | // |
| 335 | // Here, the current token start is the start of parameter range but the function ends |
| 336 | // at `foo`. Even if there's a function body, the range of parameters would still be |
| 337 | // before the comment. |
| 338 | |
| 339 | // test_err node_range_with_gaps |
| 340 | // def foo # comment |
| 341 | // def bar(): ... |
| 342 | // def baz |
| 343 | TextRange::empty(self.prev_token_end) |
| 344 | } else { |
| 345 | TextRange::new(start, self.prev_token_end) |
| 346 | } |
| 347 | } |
no test coverage detected