Regex engine implementation

The aim of this project is to create a regular expression engine using Thompson's construction

Note: This is a personal educational project and is not meant to be used inside a production environment.

At the current stage in development, the engine converts each regex expression into its corresponding non deterministic finite automata and supports only text directed matching.

Possible additional features.

• Regex-directed matching features, such as look back and capture groups.

Usage

Development

There are three empty folders: lib, bin and include which are populated by Make install.

To build to project, from the project root directory run the following commands:

> rm -rf build && mkdir build
> git submodule init && git submodule update
> cd build
> cmake ...
> make && make install

or you can run the script build.sh to execute a clean build.

Engine

Currently we have the class NDFA which a converts a regular expression to an automata by passing the regular expression as an argument:

std::string regex = "a*|a*b"
NDFA corrosponding_automata{regex};

std::string text1 {"aaaaaaaa"};
std::string text2 {"aaaaaaaab"};
std::string text3 {"bb"};

std::cout << corrosponding_automata.match(text); // prints true
std::cout << corrosponding_automata.match(text); // prints true
std::cout << corrosponding_automata.match(text3) // prints false