From: Brian Mitchell <binary42@...>
Date: 2006-04-06T10:14:32+09:00
Subject: Re: compare to strings

On 4/5/06, Dominik Bathon <dbatml@gmx.de> wrote:
> So, regular expression matching itself is not that much slower than
> String#include?.
> What makes "url2 =~ /#{url}/" slow is the creation of so many Regexp
> objects.

Ruby has some very subtle optimizations for Regexps too:

# ruby 1.8.4 (2006-03-20) [powerpc-darwin8.5.0]
GC.disable
n = ObjectSpace.each_object(Regexp){}
def foo; /abc/ end
# Note I didn't call foo.
ObjectSpace.each_object(Regexp){} - n #=> 1
1000.times {foo}
ObjectSpace.each_object(Regexp){} - n #=> 1

It is always nice to see simple optimizations like this.

Brian.