From: Armin Roehrl <armin@...>
Date: 2002-10-22T20:18:30+09:00
Subject: Re: newby asks: giving regexps as argument for funvtions


> i want to pass a regular expression as a parameter to ruby. Tthe following
> code snippet can be made easier but it shows the principle I want to
> understand:
>
> def     findPosRE(str, re)
>     m = %r{re}.match(str)
>     return m.begin(0)
> end
>
>
> pos = findPosRE ("hey you behind the wall", "/behind/")
>
>
> This gives the error:
>
> -->undefined method 'begin' for nil (NameError)
>
> How I convince ruby that the local variable m is a MatchData object, so the
> begin() method can be sent to m ?
>

You can pass a RE directly as a paramter to the Method you are calling.
No need to pass a string and recreate a regular expression. 

def  findPosRE(str, re)
     m = re.match(str)
     m.begin(0) if m!=nil 
end

pos = findPosRE ("hey you behind the wall", /behind/) 

Hope this is what you wanted,
	-A.
-----------------------------------------------
Armin Roehrl, http://www.approximity.com