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Integrate purescript-cst #3555
Description
Activity
Fixes
- Parser backtracking issues with nested arrays #2690
- Excessive parser backtracking in lambda arguments #3262
- Poor compile time performance with deeply nested types #3376
- Parser does not allow combination of function guards and case guards #3443
- Many of the things in Language grammar deprecations #3517
- Inline type annotations have wrong precedence #3554
purescript-cst currently adds some stuff to account for a few of the things mentioned in #3517 so more code in the wild parses, but it can be removed (particularly stuff around
caseindentation).This would also fix #3549.
Some other things it accounts for:
if/then/elseindosyntax. You can chain them without stair-stepping.- It fixes error positions in general so they are the correct span and don't include whitespace/comments. This obviates the need for all the heuristics
psauses to find the minimal span for an error. - It fixes the issue where the last token in a source file has the wrong span.
Reacted by Vladimir Kalnitsky and no longer on github
https://github.com/natefaubion/purescript-cst is at the point where it can parse and compile anything you throw at it (modulo intended breaking changes). It's faster, has better error reporting for many cases that require a lot of backtracking in the current parser, and it can serve as a basis for tooling (formatter) and a grammar specification.