[ruby-core:47164] [ruby-trunk - Feature #6693] Don't warn for unused variables starting with _

Issue #6693 has been updated by alexeymuranov (Alexey Muranov).


drbrain (Eric Hodel) wrote:
> Why should we break compatibility with ruby 1.9?
> 
> RDoc uses double assignment to avoid the unused variable warning for use by ERb via a binding.  The syntax error would break RDoc, so I dislike it.

I am sorry, was this about my proposal? I was not suggesting to raise an error, i just suggested that `_` be treated as any other variable, for example by making it possible to repeat any variable, not just `_`.  For completely unused variables, a special syntax can be used.
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Feature #6693: Don't warn for unused variables starting with _
https://bugs.ruby-lang.org/issues/6693#change-28843

Author: marcandre (Marc-Andre Lafortune)
Status: Feedback
Priority: Low
Assignee: 
Category: core
Target version: 2.0.0


Currently, variables which are set but not used will generate a warning (ruby -w), except if they have the special name "_".

So best practice is to use "_" for all unused variables. This does not encourage readable code.

    # Currently must read:
    _, _, _, suffix = parse_name

    # could read:
    _first, _middle, _last, suffix = parse_name

We should not warn for unused variables starting with a "_".

This would create an option (but no obligation) to use more descriptive names than "_" without generating warnings.



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