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

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
[download]

Output:

123456789
456789
789
[download]

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.

Comment on Re: "ee" in Regular Expression: version issue? Select or Download Code

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Re^2: "ee" in Regular Expression: version issue? by kennethk (Abbot) on Dec 03, 2012 at 20:23 UTC
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. #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l] [select]
Re^3: "ee" in Regular Expression: version issue? by Kenosis (Priest) on Dec 03, 2012 at 20:32 UTC
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;` [download] The substituting expression is problematic w/o either being interpolated via `"$1$2$3"` or concatenated using `$1.$2.$3`.	[reply] [d/l] [select]