From: mathew <meta@...>
Date: 2005-07-30T05:06:02+09:00
Subject: Re: Sed -> Ruby : .. and ...

Keith Fahlgren wrote:
> On Thursday 28 July 2005 5:46 pm, mathew wrote:
>>working_file.gsub!(/(?=BEGIN RANGE)(.*?)(?=END RANGE)/m) {||
>>   $1.gsub(/MATCH/m, 'REPLACEMENT')
>>}
> 
> Matthew pointed out an easier way to get around it but I had rejected 
> that method from the start because I wanted to be able to nest ranges 
> (like I can in sed).

Oh, well, in that case, let's make my 3 lines into an iterator:

class String
   # Execute a code block on the substring starting with startstring and
   # ending with endstring, and return the result
   def in_range(startstring, endstring)
     return gsub(/(?=#{startstring})(.*?)(?=#{endstring})/m) {||
       yield($1)
     }
   end
end

Example usage:

puts data.in_range('BEGIN RANGE', 'END RANGE') {|subdata|
   subdata.in_range('NESTED RANGE', 'END OF NESTED RANGE') {|x|
     x.gsub('MATCH', 'REPLACEMENT')
   }
}


mathew
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