Re: "ee" in Regular Expression: version issue?

[Kenosis]

Try concatenating the vars for use in the substitution:

use strict;
use warnings;

my $lhs = '(\d*?)-(.*?)-(.*)';
my $rhs = '$1.$2.$3';

while ( my $var = <DATA> ) {
    chomp $var;
    $var =~ s/$lhs/$rhs/ee;
    print $var, "\n";
}

__DATA__
123-456-789
-456-789
789

Output:

123456789
456789
789

From the error message, it appears that the results of the first evaluation is ambiguous to the interpreter when it attempts to evaluate it without the concatenation operator.

[kennethk]

Or use straight interpolation: my $rhs = '"$1$2$3"';. The key here is that the string literal present after the initial eval (which subs $rhs to its value) is valid Perl code.

[Kenosis]

Yes, excellent. Perhaps the enclosing double-quotes (also) helps to disambiguate the expression. After the first eval, the interpreter sees this:

$var =~ s/(\d*?)-(.*?)-(.*)/$1$2$3/ee;

The substituting expression is problematic w/o either being interpolated via "$1$2$3" or concatenated using $1.$2.$3.