Complete regex literal lexing #1463
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hamishknight
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ahoppen
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Mar 30, 2023
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@ahoppen Addressed review feedback, let me know what you think. Also noticed that we needed to properly classify the prefix operators we're splitting, so pushed a commit to fix that. |
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- Run swift-format over them - Update expectations now that we diagnose unterminated regex literals - Remove semantic errors - Fix test splitting in a few cases - Add TODOs where we should error
We currently track the previous raw token kind, but that is not sufficient to identify keyword kinds. Additionally store the keyword kind.
The SwiftSyntax parser doesn't have a way of disabling bare slash regex literals, so this is unnecessary.
Many of these can fall through to the default case to lex the operator. Also factor out `lexPostfixOptionalChain` in preparation for a bit of custom state transition logic.
Generalize in preparation for its use by regex literals.
The previous regex literal lexing logic didn't implement all the heuristics needed to parse all the regex literals that the old C++ parser handles. Update it with the heuristics it needs, and better handle diagnostics for invalid cases. This unfortunately requires a bit of lexical hackery, including a heuristic to classify previous token kinds to determine if we're in regex literal position, but it's needed to handle pathological cases such as `x /^ y/` where there's an ambiguity with a binary operator.
Previously we always produced `.prefixOperator`, which is wrong for cases like prefix `&`, `=`, and `?` which should produce different token kinds. Factor out the classification code, and use it to produce the correct token kind.
We can confidently lex unless we have a previous token that indicates that we're in an argument list. In such a case, an unapplied operator can be parsed, and we want to ensure we maintain that behavior.
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@swift-ci please test |
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@swift-ci please test Windows |
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The previous regex literal lexing logic didn't implement all the heuristics needed to parse all the regex literals that the old C++ parser handles. Update it with the heuristics it needs, and better handle diagnostics for invalid cases.
This unfortunately requires a bit of lexical hackery, including a heuristic to classify previous token kinds to determine if we're in regex literal position, but it's needed to handle pathological cases such as
x /^ y/where there's an ambiguity with a binary operator.Resolves #1059
rdar://102213809