in reply to Constructing a list of regexes

I thought of another question while reading these responses. If I want to read in the substitution value from a file and the substitution contains backreferences, how can I make that work? For example: 
my $new_value='$2 and $1';
my $string="(Jack) and (John)";
my $regex=qr/$string/;
$string=~s/$regex/$new_value/;

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This obviously won't work how I intend, but how would I do this?

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Re: Re: Constructing a list of regexes
by tall_man (Parson) on Feb 20, 2003 at 22:42 UTC
    The following will work. There was another problem with your example. "(Jack) and (John)" the literal string, does not match itself as a pattern with capturing parentheses. 
    my $new_value='$2 and $1';
my $string="(Jack) and (John)";
my $regex=qr/$string/;
$string = "Jack and John";
eval "\$string=~s/\$regex/$new_value/";
print $@ if $@;
print "$string\n";

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