Re: Re: evaluating $1 in a replace string

Regarding: Well, I thought doing a s//e on it would be the ticket, but apparently not.

It takes a little extra work, but it is certainly do-able...

#!/usr/bin/perl -w
use strict;

my $find = 'proof(\S+)';
my $rpl  = '"read$1"';
my $text = 'proofing is proof it needed to be proofed';

if ($text =~ s/$find/$rpl/ee) {
    print "1st replacement made:\n\t$text\n";
}
[download]

The double /ee is needed. The first /e sub's in the value of $rpl. The second /e evaluates that and DWIM's.

The nested quotes are needed in defining $rpl because without the inner double-quotes, the second /e fails. Another way to do that bit (and this may help in understanding) would be: my $rpl = '"read" . $1'; You have to get both the quoting and the /ee right for the thing to work as intended.

HTH

------------------------------------------------------------
"Perl is a mess and that's good because the
problem space is also a mess." - Larry Wall

Comment on Re: Re: evaluating $1 in a replace string Select or Download Code

Replies are listed 'Best First'.
Re: Re: Re: evaluating $1 in a replace string by Fletch (Bishop) on Jul 08, 2002 at 11:41 UTC
ObSecurity: Of course remember that this is an `eval`, so be sure to turn tainting on and watch where you're getting your input if what's winding up in $1 could come from an untrusted source (i.e. from a filthy user :).	[reply] [d/l]
Re: Re: Re: evaluating $1 in a replace string by Oaks (Novice) on Jul 08, 2002 at 06:24 UTC
Triple sweetness! Now I understand. I think I'll use the following version, because it gives me the same end result (having a double-quoted replacement expression on the final evaluation) and allows me to use the replacement expression as it is given to me. `#!/usr/bin/perl -w use strict; my $find = 'proof(\S+)'; my $rpl = 'read$1'; my $text = 'proofing is proof it needed to be proofed'; if ($text =~ s/$find/"\"$rpl\""/ee) { print "1st replacement made:\n\t$text\n"; }` [download]	[reply] [d/l]