[ruby-core:93414] [Ruby trunk Bug#15708] Implicit numbered argument decomposes an array
From:
eregontp@...
Date:
2019-06-28 17:26:24 UTC
List:
ruby-core #93414
Issue #15708 has been updated by Eregon (Benoit Daloze).
I think we don't need a new ticket.
This ticket description explains the problem and I argue it is bug, even if the current behavior was intended by nobu.
Let's let matz judge.
Also, if the behavior is kept we should have a clear reason written on this ticket.
I see no reason on the ticket besides "intended" which doesn't explain the rationale, so I think the discussion shouldn't be closed.
OTOH I see usages which are broken by this behavior (e.g., array_of_arrays and map), and yet no answer to that.
----------------------------------------
Bug #15708: Implicit numbered argument decomposes an array
https://bugs.ruby-lang.org/issues/15708#change-78956
* Author: sawa (Tsuyoshi Sawada)
* Status: Rejected
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version:
* ruby -v: 2.7.0dev
* Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
In the following, `@1` refers to the entire item iterated:
```ruby
a = [1, 2, 3]
a.map{|x| x} # => [1, 2, 3]
a.map{@1} # => [1, 2, 3]
```
whereas in the following, `@1` refers to the first item achieved by decomposing the item iterated, behaving the same as `x` given by `|(x)|` rather than by `|x|`:
```ruby
a = [[1], [2], [3]]
a.map{|x| x} # => [[1], [2], [3]]
a.map{|(x)| x} # => [1, 2, 3]
a.map{@1} # => [1, 2, 3]
```
Is this intended?
---Files--------------------------------
single-implicit-arg-no-destructure.diff (471 Bytes)
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