perl: passing subroutines rexexp replace with search results - regex

Question

i have the following perl subroutine:
sub rep {
defined ($filein = shift) || die ("no filein");
defined ($fileout = shift) || die ("no fileout");
$look = shift;
$replace = shift;
open (infile, "$filein")|| die;
open (outfile, "> $fileout")|| die;
while (<infile>) {
s/$look/$replace/g;
print outfile;
}
(close the files)
}
and the following text:
kuku(fred) foo(3)
kuku(barney) foo(198)
i want to call it with the following structures:
$look = kuku\((\w+)\) foo \((\d+)\),
$replace = gaga\(($1)\) bar\(($2)\).
but when i called the sub with the following (and it's variations), i couldn't make it accept the $1, $2 format:
&rep ($ARGV[0], $ARGV[1],
"kuku\\(\(\\w+\)\\) foo \\(\(\\d+\)\\)" ,
"gaga\\(\(\$1\)\\) bar\\(\(\$2\)\\)");
all i get is:
gaga($1) bar($2)
gaga($1) bar($2)
what am i doing wrong?
how can i make the subroutine identify the $1\ $2 (...) as the search results of the search and replace?

Answer 1

I'm not sure if substitution part in regex can be set in a way you want it without using eval /e, so this is how I would write this.
qr// parameter is real regex, followed by callback in which $_[0] is $1
rep( $ARGV[0], $ARGV[1], qr/kuku\((\w+)\) foo \((\d+)\)/, sub { "gaga($_[0]) bar($_[1])" } );
sub rep {
my ($filein, $fileout, $look, $replace) = #_;
defined $filein or die "no filein";
defined $fileout or die "no fileout";
open (my $infile, "<", $filein) or die $!;
open (my $outfile, ">", $fileout) or die $!;
while (<$infile>) {
s/$look/$replace->($1,$2)/ge;
print $outfile;
}
# (close the files)
}
This could be even more simplified by just passing callback which would change $_.
rep( $ARGV[0], $ARGV[1], sub { s|kuku\((\w+)\) foo \((\d+)\)|gaga($1) bar($2)| } );
sub rep {
my ($filein, $fileout, $replace) = #_;
defined $filein or die "no filein";
defined $fileout or die "no fileout";
open (my $infile, "<", $filein) or die $!;
open (my $outfile, ">", $fileout) or die $!;
while (<$infile>) {
$replace->();
print $outfile;
}
# (close the files)
}