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From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: affectation to $1
Message-ID: <10479@jpl-devvax.JPL.NASA.GOV>
Date: 20 Nov 90 18:51:06 GMT
References: <STEF.90Nov19220552@zweig.sun>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 37

In article <STEF.90Nov19220552@zweig.sun> stef@zweig.sun (Stephane Payrard) writes:
: 
: 
: using perl level 36 on a Sun 4/110 running SunOS 4.1:
: 
: I want to convert to lower case a string I have
: matched. I want to do it in place (in $1);
: I discover that I can't write to $1;
: Is this a bug or a known/justified feature?

$1, $2, etc. are readonly currently.  What would it mean to say this?

	$x = 'foo';
	$x =~ /(fo*)/;
	$x = 'bar';
	$1 =~ y/a-z/A-Z/;


: demonstrated by the following script.
: 
: #! /usr/local/bin/perl
: $_='A';
: m/(.*)/;
: $1 =~ y/A-Z/a-z/;
: print "I expect 'a'; I get '$1'\n";
: $1='B';
: print "I expect 'b'; I get '$1'\n";

There are two ways to do this.

    s#(.*)#($tmp = $1) =~ y/A-Z/a-z/, $tmp#e;

or

    /.*/ && substr($_, length($`), length($&)) =~ y/A-Z/a-z/;

Larry