Re^3: Variable substitute and capturing

It did work .. i'm guessing cause $search is from qr// ..

use strict;
use warnings;
my $s = "foobar";
my $search=qr/(foo)(bar)/;
my $replace="\$1-\$2";
my $perl = "\$s =~ s/$search/$replace/";
warn $perl;
eval $perl;
print $s;
__OUTPUT__
$s =~ s/(?-xism:(foo)(bar))/$1-$2/ at -e line 1.
foo-bar
[download]

I guess escaping $search is better though so that each eval call is dynamic on both ends (search & replace)..

Also, i had tried the other way, but got an output of "0" instead of "foo-bar":

perl -le '$s = foobar; $search=qr/(foo)(bar)/; $replace="\$1-\$2"; $s 
+=~ s/$search/eval $replace/e; print $s'
[download]

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Re^4: Variable substitute and capturing by ikegami (Patriarch) on Jan 16, 2006 at 17:08 UTC
You're right. Even without `qr//`. I've updated my post. `# qr & no eval $s = qr/\\/; $t = "\\\\"; $t =~ s/$s/!/; print("$t\n"); # qr & eval $s = qr/\\/; $t = "\\\\"; eval "\$t =~ s/$s/!/"; print("$t\n"); # qr & no stringification $s = qr/\\/; $t = "\\\\"; eval "\$t =~ s/\$s/!/"; print("$t\n"); print("\n"); # qq & no eval $s = "\\\\"; $t = "\\\\"; $t =~ s/$s/!/; print("$t\n"); # qq & eval $s = "\\\\"; $t = "\\\\"; eval "\$t =~ s/$s/!/"; print("$t\n"); # qq & no stringification $s = "\\\\"; $t = "\\\\"; eval "\$t =~ s/\$s/!/"; print("$t\n");` [download] The regexp still gets stringified and recompiled, though. This all goes to prove the value of a template system.	[reply] [d/l] [select]

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Re^4: Variable substitute and capturing
by ikegami (Patriarch) on Jan 16, 2006 at 17:08 UTC

qr//

# qr & no eval
$s = qr/\\/;
$t = "\\\\";
$t =~ s/$s/!/;
print("$t\n");

# qr & eval
$s = qr/\\/;
$t = "\\\\";
eval "\$t =~ s/$s/!/";
print("$t\n");

# qr & no stringification
$s = qr/\\/;
$t = "\\\\";
eval "\$t =~ s/\$s/!/";
print("$t\n");

print("\n");

# qq & no eval
$s = "\\\\";
$t = "\\\\";
$t =~ s/$s/!/;
print("$t\n");

# qq & eval
$s = "\\\\";
$t = "\\\\";
eval "\$t =~ s/$s/!/";  
print("$t\n");

# qq & no stringification
$s = "\\\\";
$t = "\\\\";
eval "\$t =~ s/\$s/!/";
print("$t\n");
[download]

The regexp still gets stringified and recompiled, though.

This all goes to prove the value of a template system.

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[select]