From: "zw963 (Wei Zheng)" <noreply@...>
Date: 2021-11-06T12:36:27+00:00
Subject: [ruby-core:105961] [Ruby master Feature#18291] When use =~ with named group, if regex is on the right side, variable not defined.

Issue #18291 has been updated by zw963 (Wei Zheng).


jeremyevans0 (Jeremy Evans) wrote in #note-1:
> `regexp.rdoc` documents that the literal regexp must be on the left hand side in order to assign to local variables, so this is not a bug.  Switching to feature request.

Hi, Jeremy, thank you for answer, yes, maybe it is a feature, not a bug, but, i guess do some trick specially only for this named regexp group matching to make variable is always available maybe is possible.

----------------------------------------
Feature #18291: When use =~ with named group, if regex is on the right side, variable not defined.
https://bugs.ruby-lang.org/issues/18291#change-94508

* Author: zw963 (Wei Zheng)
* Status: Open
* Priority: Normal
----------------------------------------
Following code not work.


```rb
if "Billy Zheng" =~ /(?<first_name>\w+)\s+(?<last_name>\w+)/
  p first_name
  p last_name
end
# NameError: undefined local variable or method `first_name' for main:Object
```

But, if we switch left and right between =~

```rb
if /(?<first_name>\w+)\s+(?<last_name>\w+)/ =~ "Billy Zheng"
  p first_name
  p last_name
end
# => "Billy"
# =>"Zheng"
```

I know ruby keep this same behavior since 1.9, but i am curious if we can improve this?

I consider this as a bug, because that not good, when i want to use this way, i have to
take care must write regexp before =~

Thank you.







-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>