Could you clarify? I read it thrice, and I think you want to match a given pattern when it appears as a literal. As in not as part of a comment or a string.
What your asking for is pretty tricky to do as a single regexp. Because you want to skip strings. Multiple strings in one line would complicate matters.
I wouldn't even try to do it in one regexp. Instead, I'd pass each line through a filter first, to remove strings, and then comments in that order. And then try and match your pattern.
In Perl because of it's regexp processing power. Assuming @lines is a list of lines you want to match, and $pattern is the pattern you want to match.
@matches =[];
for (@lines){
$line = $_;
$line ~= s/"[^"]*?(?<!\)"//g;
$line ~= s/'.*//g;
push @matches, $_ if $line ~= m/$pattern/;
}
The first substitution finds any pattern that starts with a double quotation mark and ends with the first unescaped double quote. Using the standard escape character of a backspace.
The next strips comments. If the pattern still matches, it adds that line to the list of matches.
It's not perfect because it can't tell the difference between "a\\" and "a\" The first is usually a valid string, the later is not. Either way these substitutions will continue to look for another ", if one isn't found the string isn't thrown out. We could use another substitution to replace all double backslashes with something else. But this will cause problems if the pattern you're looking for contains a backslash.