Perl regexp how to escape only some chars

Question

I have a string $regexp_as_string

Now I want to "convert" it into an regex / use it as regexp

if ($text_to_search =~ $regexp_as_string)
{
...
}

Now there are characters like "." and I want to automaticly escape them - \Q and \E should do that

 if ($text_to_search =~ /\Q$regexp_as_string\E/)
    {
    ...
    }

Is there a way to specify a list of characters that should be auto escaped? Because at the moment that way auto escapes for example "|" , but I want to keep that.

Answer 1

You can prepare the string using quotemeta, then remove backslashes selectively. E.g.:

my $str = quotemeta('foo${}|'); 
$str =~ s/\\(?=[|])//g; 
say $str;

Output:

foo\$\{\}|

Add any characters you want not escaped to the character class in the substitution, e.g. [|?()].