Re: [FWP] Re: Receipts

[Jeff Pinyan <jeffp@crusoe.net>]

On Sep 11, igp_list2@tesco.net said:

>On Mon, 11 Sep 2000 at 13:24:02 +0100, Leon Brocard wrote:
>> Philip Newton sent the following bits through the ether:
>> > or FWP
>> Well, here's as good a start as any:
>
>> % perl -ne 'print if $_=~/(.)\1(.)\2(.)\3/' /usr/dict/words  
>> bookkeeper
>> bookkeepers
>> bookkeeping
>
>    perl -ne '/((.)\2){3}/&&print' /usr/dict/words
>(I wondered if this would work, and it surprised me a little that it
>did.)

If you look at the -mre=debug output, you'll see why:

compiling RE `((.)\2){3}'
size 16 first at 7
   1: CURLYX {3,3}(15)
   3:   OPEN1(5)
   5:     OPEN2(7)
   7:       ANY(8)
   8:     CLOSE2(10)
  10:     REF2(12)
  12:   CLOSE1(14)
  14:   WHILEM(0)
  15: NOTHING(16)
  16: END(0)

You'll find that $2 is the last letter repeated.  Just as if you'd done:

  "alphabet" =~ /(.)+/;

$1 is 't', not 'a'.

-- 
Jeff "japhy" Pinyan     japhy@pobox.com     http://www.pobox.com/~japhy/
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