Python: Allow use of match as an identifier
#19895
Open
+31,674
−29,909
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This previously only worked in certain circumstances. In particular, assignments such as `match[1] = ...` or even just `match[1]` would fail to parse correctly. Fixing this turned out to be less trivial than anticipated. Consider the fact that ``` match [1]: case (...) ``` can either look the start of a `match` statement, or it could be a type ascription, ascribing the value of `case(...)` (a call) to the item at index 1 of `match`. To fix this, then, we give `match` the identifier and `match` the statement the same precendence in the grammar, and additionally also mark a conflict between `match_statement` and `primary_expression`. This causes the conflict to be resolved dynamically, and seems to do the right thing in all cases.
IdrissRio
approved these changes
Jun 27, 2025
Oh yes, I completely forgot to do that. We usually do that for any change, no matter how small (unless it literally doesn't touch any code at all), so thanks for the reminder! |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This previously only worked in certain circumstances. In particular, assignments such as
match[1] = ...or even justmatch[1]would fail to parse correctly.Fixing this turned out to be less trivial than anticipated. Consider the fact that
can either look the start of a
matchstatement, or it could be a type ascription, ascribing the value ofcase(...)(a call) to the item at index 1 ofmatch.To fix this, then, we give
matchthe identifier andmatchthe statement the same precendence in the grammar, and additionally also mark a conflict betweenmatch_statementandprimary_expression. This causes the conflict to be resolved dynamically, and seems to do the right thing in all cases.