Re: How to do regex backreferences within $variable replacement text?

Finally got a moment away from child minding :). Here's a non-eval technique:

use warnings;
use strict;

my $udStr = "abcabcabc";
my $udSearch = '(a)';
my $udRep = '---$1---';

print "before: $udStr\n";
my $before = $udStr;
$udStr =~ s/$udSearch/$udRep/;
my @starts = @-;
my @ends = @+;

for (1..$#starts)
  {
  my $replace = substr $before, $starts[$_], $ends[$_] - $starts[$_];
  $udStr =~ s/\$$_(?=\D)/$replace/;
  }
print "after: $udStr\n";
[download]

Prints:

before: abcabcabc
after: ---a---bcabcabc
[download]

This still doesn't fix (?{...}) and (??{...}) in $user_defined_search, but those could be filtered.

Perl is Huffman encoded by design.

Comment on Re: How to do regex backreferences within $variable replacement text? Select or Download Code

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Re^2: How to do regex backreferences within $variable replacement text? by Hue-Bond (Priest) on Sep 18, 2005 at 01:26 UTC
One can also add a 'g' to lines 10 and 17 to replace all ocurrences of $udSearch. -- David Serrano	[reply]
Re^3: How to do regex backreferences within $variable replacement text? by GrandFather (Saint) on Sep 18, 2005 at 01:33 UTC
Yes, I intended to :(. Must be in Sunday mode. Perl is Huffman encoded by design.	[reply]
Re^2: How to do regex backreferences within $variable replacement text? by Hue-Bond (Priest) on Sep 18, 2005 at 02:20 UTC
Before seeing your code, I had tried something similar but limited only to $1. Now I've worked on it a bit more and came up with this. Just another WTDI. use warnings; use strict; my $user_defined_string = "There's more than one way to do it (more th +an one)."; my $user_defined_search = '(more)(.*?)(one)'; my $user_defined_replace = '<b>$1</b>$2<b>$3</b>'; my (@subs) = $user_defined_string =~ /$user_defined_search/; for my $sub (1..@subs) { $user_defined_replace =~ s/\$$sub/$subs[$sub-1]/ge; } print "mangled replace: $user_defined_replace\n"; $user_defined_string =~ s/$user_defined_search/$user_defined_replace/g +e; print "after: $user_defined_string\n"; __OUTPUT__ mangled replace: <b>more</b> than <b>one</b> after: There's <b>more</b> than <b>one</b> way to do it (<b>more</b> t +han <b>one</b>). [download] As we can see, the user is expected to have a deep understanding of Perl regexes (non-greediness in this example) if she wants to do fancy stuff ;^). -- David Serrano	[reply] [d/l]
Re^3: How to do regex backreferences within $variable replacement text? by Skeeve (Parson) on Sep 18, 2005 at 07:32 UTC
This simply does not work! Replace the search text with "There's more than one way to do it (more or less than one)." and you'll see what I mean. you don't do any backreferencing but a simple replacement with the first strings found. `$\=~s;s.;q^\|D9JYJ^^qq^\//\\\///^;ex;print`	[reply] [d/l]