C++ Regex Speed Optimize

Question

hello this is my c++ regex

regex MyRGX(R"~((\w*)\s*[(]([^;]*)[)]\s*[;])~");

and this is my string

Data1 (

   anything1

);

this regex get Data1 and everything exists between (); with any condition. but when i have more than 50 blocks like Data1 , this regex search speed is going to be lower than equivalent regex in pcre. i think this regex that i have, isn't optimize for speed. do you have any suggestion to increase speed of this regex with this conditions (get everything exists between (); and ...) ?

Answer 1

As I suspected from your previous question, this looks like a case where Regex isn't the most logical solution.

"Regex" comes from "Regular Expressions" which describe "Regular Languages". And languages with matched parentheses (like C++ itself) are not regular. Now, what we call "regex" has evolved to include some non-regular languages, but that's not optimal.

In this case, it looks like a perfectly ordinary parser would work. As I understand it, the goal is to look for anything between ( and ); . So do a simple text search forward for ( , backwards for ); . Check that both are found and that ( precedes ); , then just use the index pair found to extract the substring.