Question

How using regexp replace something in code that is not a comment?

..PATTERN.. PATTERN // .. PATTERN ..

to

..ANOTHER.. ANOTHER // .. PATTERN ..

Comments can be // or /* */

Regexp to find comments is:

/\*(.|[\r\n])*?\*/|(//.*)

Answer 1

You can easily do this for single line comments by using a negative lookbehind (but still prone to problem of literal string of the form “….//…..”):

string target = "replace // don't replace";
var output = Regex.Replace(target, "(?<!//.*)replace", "new string");
Console.WriteLine(output); //  new string // don't replace

Maybe this could work for multiline:

string target = 
    @"replace;
/*
* don't replace
*/
replace;
    ";

var output = Regex.Replace(target, @"(?<!./\*\s*)replace(?!\s*\*/)", "new string", RegexOptions.Singleline);

Console.WriteLine(output); 

output:

new string;
/*
* don’t replace
*/
new string;