You could also use quotemeta(), which is how the \Q is implemented. Ie., 

$formula = '(4+5)';
$bit = quotemeta $formula;
if ( $formula =~ /$bit/ ) {
  print "yeah\n"; 
} else { 
  print "Oh no!\n"; 
}
This will handle literal '$' and '@'.

In reply to Re: How do I escape metacharacters in a user-defined string? by Perlmage
in thread How do I escape metacharacters in a user-defined string? by Coyo

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