PEP 634: change walrus pattern to AS pattern #1661
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Whoops, the PEP 635 half of this conflicts with another branch. I'll remove that for now. |
gvanrossum
changed the title
brandtbucher
requested changes
Oct 19, 2020
| @@ -158,7 +158,7 @@ Irrefutable case blocks | |||
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| A pattern is considered irrefutable if we can prove from its syntax | |||
| alone that it will always succeed. In particular, capture patterns | |||
| and wildcard patterns are irrefutable, as are walrus patterns whose | |||
| and wildcard patterns are irrefutable, and so are AS patterns whose | |||
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| pattern: walrus_pattern | or_pattern | ||
| walrus_pattern: capture_pattern ':=' or_pattern | ||
| pattern: as_pattern | or_pattern | ||
| as_pattern: or_pattern 'as' capture_pattern |
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I forget, do we still need/want to unify the grammars in the implementation and spec? As it currently stands, as_pattern isn't a rule, it's just folded into pattern:
pattern[expr_ty]:
| value=or_pattern 'as' target=NAME { _Py_MatchAs(value, target->v.Name.id, EXTRA) }
| or_pattern
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(this isn't the only difference, though)
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I'd like the implementation eventually to use the same grammar as the PEP. I'd rather not change the PEP (unless we find bugs) because I use the rule names (e.g. "as pattern") in the text without explanation.
Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
brandtbucher
approved these changes
Oct 19, 2020
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