in reply to Re: a word of warning about /$pattern/
in thread a word of warning about /$pattern/

This kind of thing keeps me humble, because I know that somewhere there is someone who understands exactly why this was a good idea

Its still a good idea: 

if (/foo/ or /bop/ or /fnorble/) {
  s//baz/;
}

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IOW, it means you can have several regexes try to match, and then without having to worry about which one did you can then replace the thing that was matched. I only recently came accross this feature, but sice I have its found its way into more code than I thought it would.


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demerphq

    First they ignore you, then they laugh at you, then they fight you, then you win.
    -- Gandhi

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Re^3: a word of warning about /$pattern/
by Aristotle (Chancellor) on Dec 07, 2003 at 09:43 UTC
    Huh? 
    s/foo|bop|fnorble/baz/;

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    Makeshifts last the longest.

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[d/l]

      Fair point. The example is not the best I've ever written.

      The point is that the empty regex behaviour is useful for allowing you to use m/.../ and then later s//.../ without having to match a second time. Maybe this is better 

      if ($foo and /bar/) {
   print "Condition suceeds.\n";
   if ($bloop and /bop/) {
      #...
   }
   # do other stuff, maybe even exit...
   s//baz/; # switch bar or bop with baz depending 
            # on a bunch of things that have already happened.
 }

      [download]

      Hopefully now you see the point? Sure we could probably rework the logic so this isnt needed, but I like the possibilities this opens up. :-)


      ---
      demerphq

        First they ignore you, then they laugh at you, then they fight you, then you win.
        -- Gandhi

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[d/l]
[select]
        Oh, I understand what you were getting at. I still see it as somewhat obfuscatory though. I also don't really like it conceptually, as the s/// is actually doing the match from scratch (so it's not an atomic operation). It might still be the best way to go about this problem, I don't know: I don't remember ever having to have needed to implement such logic so I have no realistic example scenario to go by. I just can't help the feeling that there has to be a clearer way.

        Makeshifts last the longest.

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