This repository contains an implementation of a bare-bones regular expression matching routine. It's bare-bones because it only supports:

• A simple match routine that returns a bool indicating whether a given string matches a given regular expression.
• Strings of byte-wide characters.
• Regular expressions comprised of sequences of alphanumeric literals, the | (alternation) and * (repetition) operators, and parenthesis.

It is based on Russ Cox' description of work by Ken Thompson. A key feature of Thompson's approach is that its run-time is linear in the length of the input string, as a result of not using back-tracking.

I wrote this as an exercise to gain some familiarity with C++, and it's not intended for "production" use. For example, one shortcoming is that the parser uses recursion and will fail ungracefully when given a sufficiently large regular expression as input.