From: Shashank Date <sdate@...>
Date: 2002-11-15T12:22:11+09:00
Subject: Re: regex help

Nice !

Learnt a lot from your examples ...
Thanks !

"ahoward" <ahoward@fsl.noaa.gov> wrote in message
> On Thu, 14 Nov 2002, why the lucky stiff wrote:
>
> [snip]
> stiff>   quote1_re = /((?:''|[^'])+)/
> [snip]
>
> TESTING REGEX ((?:''|[^'])+)
>
>         '        did not match        -
>         ''       matched           ('')
>         '''      matched           ('')
>         ''''     matched         ('''')
>         'a       matched            (a)
>         a'       matched            (a)
>         ''a      matched          (''a)
>         a''      matched          (a'')
>         '''a     matched           ('')
>         a'''     matched          (a'')
>         ''''a    matched        (''''a)
>         a''''    matched        (a'''')
>
> TESTING REGEX (?:^|[^'])('(?:[^']|'')*')(?:[^']|$)
>
>         '        did not match        -
>         ''       matched           ('')
>         '''      did not match        -
>         ''''     matched         ('''')
>         'a       did not match        -
>         a'       did not match        -
>         ''a      matched           ('')
>         a''      matched           ('')
>         '''a     did not match        -
>         a'''     did not match        -
>         ''''a    matched         ('''')
>         a''''    matched         ('''')
>
>
> THE PROGRAM
>
>   #!/usr/bin/env ruby
>
>   regexs = [
>     %r{((?:''|[^'])+)},
>     %r{(?:^|[^'])('(?:[^']|'')*')(?:[^']|$)}
>    ]
>   strings = %w(
>        ' '' ''' '''' 'a a'
>        ''a a'' '''a a''' ''''a a''''
>       )
>   regexs.each do |r|
>     puts "\nTESTING REGEX #{r.source}\n\n"
>     strings.each do |s|
>       m = r.match s
>       format = "\t%-8.8s %-13.13s %8.8s\n"
>       if m
> printf format, s, 'matched', "(#{m[1]})"
>       else
> printf format, s, 'did not match', '-'
>       end
>     end
>   end
>
>
>
>
> (?:^|[^'])('(?:[^']|'')*')(?:[^']|$)
>
>   * beginning with the start of string or not a '
>   * followed by a '
>   * followed by zero or more of not ' or ''
>   * followed by a '
>   * ending with the end of string or not a '
>   * the quoted string is captured, nothing else is
>
>
> -ara
>