Re^2: Interpolate into replacement with s//?

[ikegami]

$replace contains a template. Therefore, you need a template engine to process it. The only existing template module I know that can process that language is String::Interpolate. (Yeah, it has a weird interface.)

Alternatively, if $replace actually contained a string literal (i.e. Perl code), you could use eval to evaluate it.

$string = 'ABC';
$search = qr/^(A)/;
$replace = '"$1Z"';
$string = s{$search}{
   my $replacement = eval($replace);
   die $@ if $@;
   $replacement
}eg;
say $string;

[tchrist]

ikegami wrote:

$replace contains a template. Therefore, you need a template engine to process it.

Aw /gee whiz, we don’t need no stinkin’ modules for such a trivial task. Merely render unto Perl that which is Perl’s:

use v5.14;
my $string  =  q/ABC/;
my $search  = qr/^(A)/;
my $replace =  q/"Z\l$1Z"/;
$string =~ s/$search/$replace/gee;
say $string;

Which when run duly prints out ZaZBC.

[philkime]

Hmm, I tried /gee but $replace isn't directly assigned, it's from elsewhere so say I'd read $replace from another file and it was a string 'Z$1Z' then this doesn't seem to work?

[ikegami]

It doesn't matter where the string came from. Notice he changed Z$1Z (not Perl code) to "Z$1Z" (Perl code). So you'd need to either change the file or add quotes to what you read from the file.