From: Robert Klemme <shortcutter@...>
Date: 2008-10-26T19:34:51+09:00
Subject: Re: regular expressions and conditionals

On 26.10.2008 01:02, Caleb Clausen wrote:
> On 10/25/08, Matt Harrison <iwasinnamuknow@genestate.com> wrote:
>> I'm writting a little program to convert some source files to html.
>>
>> I'm using regexp's to determine the content of each line and format it
>> accordingly. For example, if the line starts with a #, then it should be
>> output with a div (and id set to 'comment').
>>
>> The problem is with matching the regular expressions. If I do this:
>>
>> f = File.new("myfile", "r")
>> while !f.eof?
>>   line = f.gets
>>
>>   if line.match(/^# (.*)/)
>>     puts "<div id='comment'>#{line.match(/^# (.*)/)[0]}</div>"
>>   end
>> end
>>
> 
> I think what you're trying to write is a little more like this:
> f = File.new("myfile", "r")
> while line = f.gets
>   if line.match(/^# (.*)/)
>     line="<div id='comment'>#{line.chomp}</div>\n"
>   end
>   puts line
> end

Even better is

# Use the block form of File.open!
File.new("myfile", "r") do |f|
   f.each do |line|
     line.chomp!
     case line
     when /^# *(.*)/
       puts "<div id='comment'># {$1}</div>"
     else
       puts line
     end
   end
end

or, for that matter

File.foreach("myfile") do |line|
   line.chomp!
   case line
   when /^# *(.*)/
     puts "<div id='comment'># {$1}</div>"
   else
     puts line
   end
end

Kind regards

	robert