From: "drbrain (Eric Hodel)" <drbrain@...7.net>
Date: 2012-07-25T06:50:56+09:00
Subject: [ruby-core:46740] [ruby-trunk - Bug #6723] Global variable scoping problem.


Issue #6723 has been updated by drbrain (Eric Hodel).


These are described as "Special global variables" and are described as "thread-local and method-local" in the Regexp documentation.  I updated a reference to them in re.c, but the existing documentation should be sufficient.
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Bug #6723: Global variable scoping problem.
https://bugs.ruby-lang.org/issues/6723#change-28411

Author: iblue (Markus Fenske)
Status: Closed
Priority: Normal
Assignee: drbrain (Eric Hodel)
Category: DOC
Target version: 2.0.0
ruby -v: -


This issue exists from 1.8 to ruby-head.

See the following example:

def foobar
  "Foobar".match(/^(\w*)/)
  puts $1.inspect
end

foobar
puts $1.inspect
puts global_variables.inspect

This demonstrates that $1 does not behave like a global variable. However it's listed by Kernel.global_variables as a global variable. And it's named like a global variable.

This leads to some confusion sometimes. See for example http://stackoverflow.com/q/11441782/773690

It may not be a good idea to fix this inconsistent naming, because it may break severaly things. However the fact that $1 and friends are not global variables should be clearly documented. And by the way: Ruby != Perl.

Or maybe make $1 a real global variable?


-- 
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