From: "Bartosz Dziewoński" <matma.rex@...>
Date: 2011-08-29T22:17:09+09:00
Subject: Re: String#split resets regex captures variables (Ruby 1.8.7)

2011/8/29 Josh Cheek <josh.cheek@gmail.com>:
> 2011/8/29 Bartosz Dziewoński <matma.rex@gmail.com>
>> I think it makes sense for $1, $2 etc to change any time a regex match
>> is performed anywhere in Ruby, it might be even kind of useful in some
>> perverse scenarios. That said, you shouldn't use these if you can,
>> it's a Perl relic (but I admit, sometimes it's the easiest way).
>>
> I don't, that means that if you call some method, then it can implicitly and
> unintentionally change variables you've set, and the only way to know it is
> to go digging through source code. You could empirically experiment with it,
> but say the regex was conditionally evaluated, then you'd not know it was
> used unless conditions were right, meaning it might not pop up until you
> were in production.

That's precisely why you shouldn't use them in anything except for
scripts written in 20 minutes.


2011/8/29 Robert Klemme <shortcutter@googlemail.com>:
> And actually the situation is much more friendly: $1 etc. are local to
> stack frame...
>
> ... and local to thread:
>

Fun, fun, fun. Semi-local global variables. I had no idea it's that crazy.


-- Matma Rex