[ruby-core:120108] [Ruby master Bug#20931] Using `in` as an expression requires extra parentheses
From:
"stephenprater (Stephen Prater) via ruby-core" <ruby-core@...>
Date:
2024-12-04 23:04:22 UTC
List:
ruby-core #120108
Issue #20931 has been updated by stephenprater (Stephen Prater).
That works for me - thanks for the explanation.
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Bug #20931: Using `in` as an expression requires extra parentheses
https://bugs.ruby-lang.org/issues/20931#change-110856
* Author: stephenprater (Stephen Prater)
* Status: Rejected
* ruby -v: 3.3.1
* Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
TBH - I'm not sure if this is a bug or not - but it certainly surprising behavior and I'd at least like to understand it.
Given a hash t - that can be pattern matched: `t = {a: 1, b:1 }`
``` ruby
r = t in {a: 1, c:1 } # returns `false`
r # {a: 1, c: 1} wat
```
Presumably this is because `=` binds higher than `in` - so that expression is equivalent to `(r = t) in {a: 1, c: 1}`
But in that case - why does using the results of `in` require an additional set of parentheses to avoid a syntax error when the result of the expression is used as an argument to a method?
``` ruby
puts(t in {a: 1, c: 1}) # syntax error
puts((t in {a: 1, c: 1}) # false
```
Especially since this works fine:
``` ruby
puts(case t; in { a: 1, c:1 }; true; else false; end)
```
--
https://bugs.ruby-lang.org/
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