From: Josh Cheek <josh.cheek@...>
Date: 2009-08-21T21:06:58+09:00
Subject: Re: How to convert string "/regexp/i" to /regexp/i - ?

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Sorry, it gave me what I expected, and Ruby is usually intuitive, so I
thought I got it right. This class, however, is not. I had to learn some of
it's internal logic to figure it out. (they define constants for each flag,
these constants are integers, you then have to add the values of the
constants of all the flags together to get the new options value)


class String
    return nil unless self.strip.match(/\A\/(.*)\/(.*)\Z/mx)
    regexp , flags = $1 , $2
    return nil if !regexp || flags =~ /[^xim]/m

    x = /x/.match(flags) && Regexp::EXTENDED
    i = /i/.match(flags) && Regexp::IGNORECASE
    m = /m/.match(flags) && Regexp::MULTILINE

    Regexp.new regexp , [x,i,m].inject(0){|a,f| f ? a+f : a }
  end
end

#fail cases
"regexp".to_r         # => nil
"regexp/i".to_r       # => nil
"/regexp/mk".to_r     # => nil
<<-ENDOFSTRING.to_r   # => nil
hello rEG
world exP
ENDOFSTRING
"/regexp/mk
hello rEG
world exP".to_r       # => nil

#pass cases
"/reg/".to_r          # => /reg/
"  /reg/x ".to_r      # => /reg/x
"/reg.*?exp/m".to_r   # => /reg.*?exp/m
"/regexp/x".to_r      # => /regexp/x
"/abc
def
ghi/xi".to_r          # => /abc
                      #     def
                      #     ghi/ix

"//".to_r             # => //
"/abc/i".to_r         # => /abc/i
"/abc/x".to_r         # => /abc/x
"/abc/m".to_r         # => /abc/m
"/abc/ix".to_r        # => /abc/ix
"/abc/im".to_r        # => /abc/mi
"/abc/xm".to_r        # => /abc/mx
"/abc/ixm".to_r       # => /abc/mix
"/abc/mxi".to_r       # => /abc/mix





On Fri, Aug 21, 2009 at 5:27 AM, 7stud -- <bbxx789_05ss@yahoo.com> wrote:

> Josh Cheek wrote:
> > class String
> >   def to_r
> >     Regexp.new(*strip.match(/\/(.*)\/(.*)/)[1,2])
> >   end
> > end
> >
> > "/regexp/i".to_r # => /regexp/i
> >
>
> Doesn't work in this case:
>
> str = "/reg.*?exp/m"
>
> test_str =<<ENDOFSTRING
> hello rEG
> world exP
> ENDOFSTRING
>
> ...nor when there is more than one flag.
>
>
>
>
>
> --
> Posted via http://www.ruby-forum.com/.
>
>

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