Distinguish between pseudo-class selectors and interpolation #8
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# Related Links: Addresses [Issue 7: tree-sitter parses complex declaration as pseudo-class instead of CSS custom property](tree-sitter-grammars#7). # What This commit places a guard clause around the scanner expression for detecting a pseudo-class selector colon. The guard clause ensures that the character *prior to* any `{` symbol was not the start of interpolation. I have also re-run the generate under 0.24.5, so the parser, headr files, and generated grammar have been updated to the latest & greatest version. A `tree-sitter.json` file has also been generated, and the corresponding tree-sitter clause removed from `package.json` (automatically, by tooling). # Why This declaration, which has been [added to the test cases](./test/corpus/declarations.txt). ``` div { --#{$x}--left: var(--#{$y}--right); } ``` As written, when `PSEUDO_CLASS_SELECTOR_COLON` is a valid possible symbol, the scanner clause for pseudo-class selector detection passes if a `{` is detected before encountering a `}` or `;` symbol. The expression `#{$y}` in the test case meets that criteria, the lexer result is marked incorrectly, and the parser fails to parse the declaration correctly. Adding a guard that the prior character seen was a `#` and that the `{` is not the start of a nested block identified by a pseudo-class but is, instead, part of an interpolation, fixes this issue. # Test steps 1. Run the tests under the old clause and see this failure: ``` correct / expected / unexpected 1. Interpolation on both sides of a declaration: (stylesheet (rule_set (selectors (tag_name)) (block (declaration (ERROR) (property_name (identifier) (interpolation (variable)) (identifier)) (call_expression (function_name) (arguments (identifier) (interpolation (variable)) (identifier))))))) ``` 2. Run it with the new clause and there is no more failure. :-) In fact, *all* of the tests now pass.
| @@ -49,16 +49,6 @@ | |||
| "parse": "tree-sitter parse", | |||
| "test": "tree-sitter test" | |||
| }, | |||
| "tree-sitter": [ | |||
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Change made by tree-sitter generate version 0.24.
| while (lexer->lookahead != ';' && lexer->lookahead != '}' && !lexer->eof(lexer)) { | ||
| // We need a { to be a pseudo class selector, a ; indicates a | ||
| // property | ||
| while (lexer->lookahead != ';' && lexer->lookahead != '}' && |
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This is where the actual fix begins; here I initialize a boolean to track the prior character, record it if necessary, and ignore the problematic { if possible_interpolation is still true. I then remove the possible_interpolation if the follow-on character was not a problematic {.
Man, I hate going back and writing C again.
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| { | |||
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Added by tree-sitter generate with version 0.24.
| @@ -19,17 +19,24 @@ void tree_sitter_scss_external_scanner_destroy(void *payload) {} | |||
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| void tree_sitter_scss_external_scanner_reset(void *payload) {} | |||
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| unsigned tree_sitter_scss_external_scanner_serialize(void *payload, char *buffer) { return 0; } | |||
| unsigned tree_sitter_scss_external_scanner_serialize(void *payload, | |||
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Most of this is clang_format and whatever the original code was formatted with disagreeing. The only syntactical change is marked below.
Hah! Thanks! And although this works, trying it out on the Patternfly source code revealed a whole bunch of edge cases, so I'm going to have to withdraw it and try again. It`s tree-sitter vs IBM. "Whose cuisine will reign supreme!?" |
Related Links:
Addresses Issue 7: tree-sitter parses complex declaration as pseudo-class instead of CSS custom property.
What
This commit places a guard clause around the scanner expression for detecting a pseudo-class selector colon. The guard clause ensures that the character prior to any
{symbol was not the start of interpolation.I have also re-run the generate under 0.24.5, so the parser, headr files, and generated grammar have been updated to the latest & greatest version. A
tree-sitter.jsonfile has also been generated, and the corresponding tree-sitter clause removed frompackage.json(automatically, by tooling).Why
This declaration, which has been added to the test cases.
As written, when
PSEUDO_CLASS_SELECTOR_COLONis a valid possible symbol, the scanner clause for pseudo-class selector detection passes if a{is detected before encountering a}or;symbol. The expression#{$y}in the test case meets that criteria, the lexer result is marked incorrectly, and the parser fails to parse the declaration correctly.Adding a guard that the prior character seen was a
#and that the{is not the start of a nested block identified by a pseudo-class but is, instead, part of an interpolation, fixes this issue.Test steps