From: Greg Hurrell <greg.hurrell@...>
Date: 2007-02-22T22:00:06+09:00
Subject: Re: Weird behaviour escaping special characters in a string

On 21 feb, 19:45, James Edward Gray II <j...@grayproductions.net>
wrote:
> On Feb 21, 2007, at 12:36 PM, Austin Ziegler wrote:
>
> It's probably better to use a character class [\\'] instead of  
> alternation (\\|').
>
> James Edward Gray II

I did some quick and dirty benchmarks and using a character class is a
little bit quicker. Interpolation ("\\#$1") is slower but more
readable. I guess I'll stick with the character class and no
interpolation though.

require 'benchmark'
include Benchmark

bm(6) do |x|
  x.report('alternation') { 100_000.times { "'foo'".gsub(/(\\|')/, '\\\
\\1') } }
  x.report('char class')  { 100_000.times { "'foo'".gsub(/[\\']/, '\\\\
\&') } }
  x.report('interpolation') { 100_000.times { "'foo'".gsub(/(\\|')/, "\
\#$1") } }
  x.report('interpolation with char class') { 100_000.times
{ "'foo'".gsub(/[\\']/, "\\#$&") } }
end
            user     system      total        real
alternation  0.450000   0.000000   0.450000 (  0.452661)
char class  0.390000   0.000000   0.390000 (  0.396193)
interpolation  0.540000   0.010000   0.550000 (  0.532106)
interpolation with char class  0.480000   0.000000   0.480000
(  0.485922)