Regex Interpolation

spectre has asked for the wisdom of the Perl Monks concerning the following question:

This might be a silly question, it IS the first time I've asked one here though, so I hope if it is deemed silly I'll be forgiven. Here is my quandry:

I need the $main::pageVar variable in the line below to interpolate, a
+nd I'm not sure how I would do it.

$retVal=~s/showpos\"\svalue\=\"1\"/showpos\"\svalue\=\"$main::pageVar1
+\"/;
[download]

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Re: Regex Interpolation by httptech (Chaplain) on Jun 24, 2000 at 05:16 UTC
Curly braces should do the trick here, to separate your variable name from the '1': `print "Success!\n" if $retVal =~ s/showpos=1/showpos=${main::pageVar}1/;`	[reply] [d/l]
Re: Regex Interpolation by btrott (Parson) on Jun 24, 2000 at 00:28 UTC
What you have currently should already interpolate, if I'm understanding what you mean by interpolate. You should get rid of some of those backslashes, though, because they're not needed. And change the "\s" on the right-hand side of the substitution into a " ". `$retVal =~ s/showpos"\svalue="1"/showpos" value="$main::pageVar1"/ +;` [download] This works for me.	[reply] [d/l]
RE: Re: Regex Interpolation by spectre (Scribe) on Jun 24, 2000 at 00:41 UTC
I re-wrote that line, trying to make that swap at a different place in the code, here is what I found: `print "$retVal\n"; print "Success!\n" if $retVal=~s/showpos=1/showpos=$main::pageVar1/; print "$retVal\n"; print "$main::pageVar\n";` [download] returns this: catCount=0&prodCount=36&show=prod&showpos=1&searchtxt=chip ... (The rest is irrelevant) Success! catCount=0&prodCount=36&show=prod&showpos=&searchtxt=chip 1 What I want to see here is the section "showpos=" to contain the value of $main::pageVar next to a number one. Regards, spectre -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.1 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE5U4KjQY9UwXAsuBQRAtnrAJ4tREiYW93esFhsZjLPQ21UJLPTQQCePU7A 6c5CzwVZr80Cs5vo3MJH5Ow= =7nk0 -----END PGP SIGNATURE-----	[reply] [d/l]
RE: RE: Re: Regex Interpolation by Anonymous Monk on Jun 24, 2000 at 07:48 UTC
The problem comes from the 1 at the end of $main::pageVar. Perl thinks that the variable is $main::pageVar1. To distinguish the variable from the literal 1 change the variable reference to ${main::pageVar} so that the regex looks like print "Success!\n" if $retVal=~s/showpos=1/showpos=${main::pageVar}1/;	[reply]