In your first code sample, you have:

my $re_str=qr{([0-6BS])};
$_="B";
my $ans;
if (eval m{$re_str})

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Why are you using eval? It should not be needed.

In your second code sample:

my $re_str="qr{([0-6BS])}";
$_="B";
my $ans;
if (eval m{$re_str})

[download]

The m{$re_str} will be interpreted as m/qr{([0-6BS])}/ which is looking to match something that starts with "qr". (And I'm not sure how the "{([0-6BS])}" will get interpreted as. "{" and "}" in a regex are normally used to quantify the number of matches.)

To store a regex as a hash key, you could prefix the regex with a character that won't otherwise appear as the first character of any of your hash keys. So, something like this:

#not tested, YMMV
for $key (keys %options)
{
    if ($key =~ s/^#//)
    {
        if (/$key/)
        {
            print "Match: $1\n";
        }
    }
    else
    }
        if ($_ eq $key)
        {
            print "Equals: $1\n";
        }
    }
}

[download]

In reply to Re: how to use string RE (against $_ and capture) by RonW
in thread how to use string RE (against $_ and capture) by perl-diddler

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