solatar / regextonfa

University course project on Data Structures and Algorithms

RegexToNfa Application

University course project on Data Structures and Algorithms.

The app takes a regular expression and a string as input, builds an NFA fron the regex and checks whether it accepts the string.

The application uses Shunting-Yard and Thompson's construction algorithms. Due to the nature of the latter, the app adds character '.' between concatenated characters. For example, (a|b|c)*abc becomes (a|b|c)*.a.b.c. User may enter their regex in regular form. Parentheses are used for grouping characters but they are dropped when regex is converted into postfix form.

Currently the app supports these regular expression operations (in the order of precedence): . for concatenation, | for alternation * for closure (zero or more) and + for one or more.

Requirements specification

User Manual

Implementation report

Testing report

Weekly progress

regextonfa's Issues

Code review

Downloaded zip-file 8.10.2022 at 5pm

I was not able to run the code on my computer due to the JavaFx dependencies, so I settled for just reading the code.
The quality of code seems good and comments made to the code helped a lot in reading the code. Unit testing is also comprehensive enough, testing the important classes.

Couple of suggestions:

-All the classes are currently in the same package. I think dividing UI classes and functionality classes into different packages would make things more clear.

-The method constructNfa is quite long. Would it be possible to divide it into smaller methods?

I found it quite hard to find things to suggest, which I suppose means that the project is in a really good state. Good luck with the rest of the project!

Peer review

Downloaded the project at 22.00 on October 15.

Running the application works and the tests (9) show no failures or errors.

Due to the project being about regular epressions and nfa, it takes some time to understand the code, but the code is very well commented which helps a lot. The algorithms do their job nicely.

I would divide the UI and application logic classes into different packages, and add a small explanation what each class does at the top of the class.

If I were to suggest an addition, I would include a small guide/a few examples in the UI of simple regex expressions the user can try.

Nice work and good luck with the rest of the project 👍