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From: worley@compass.uucp (Dale Worley)
Newsgroups: comp.lang.perl
Subject: Detab function
Message-ID: <1990Nov20.182049.12017@uvaarpa.Virginia.EDU>
Date: 20 Nov 90 18:20:49 GMT
Sender: mmdf@uvaarpa.Virginia.EDU (Uvaarpa Mail System)
Reply-To: worley@compass.uucp
Organization: The Internet
Lines: 26


   X-Name: Stu Donaldson

   I need a detab function written in perl.  [...] How about a one liner? :-)

This isn't even ugly:

perl -pe '$spacing = 8; 1 while s/\t/" " x ($spacing - length($`) % $spacing)/e;'

(Amazing!  The only other language I know of that can do this in one
line is Snobol!)

However, the apparently equivalent program

perl -pe '$spacing = 8; s/\t/" " x ($spacing - length($`) % $spacing)/eg;'

doesn't work, apparently because s///g doesn't work exactly as I
expect.  I expect it to perform each search and replacement, and then
start searching again in the modified string.  It appears (if I insert
a strategic print) that the successive searches are done in the
original string, and all modifications are in a copy of it.  (Is this
what we really want?  Is this documented?)

Dale Worley		Compass, Inc.			worley@compass.com
--
It is easier to get forgiveness than permission.