Phinite

Phinite is a windows desktop application that implements an approximate solution to a language theory problem. The task was to create a deterministic finite-state machine that is equivalent to a given regular expression.

In short, it is a desktop application that enables user to enter a regular expression (i.e. expression formed in a regular language) and then automatically creates a deterministic finite-state machine that is equivalent to this given expression (i.e. a directed graph-like structure that can simulate the process of parsing the give regular expression).

The app is developed in C#, using WPF (Windows Presentation Foundation) and many other libraries like Graph#, WPF Toolkit, WPF Converters, etc. It’s an open-source project. Another feature of the app is ability to generate LaTeX and then PDF file that summarizes the work that was done (i.e. how the finite-state machine was constructed) for a given input. Such report is automatically generated if a LaTeX distribution (e.g. MiKTeX, texlive, or equivalent) is present on the computer. After the finite-state machine is generated, user can supply some example words to see behaviour of the generated construct.

To layout the nodes of graphical representation of the machine, the program uses gravitational algorithm provided by Graph# library. I’ve written my own algorithm to properly layout edges and labels - to handle cases of crossing edges, case where there is an edge from A to B as well as from B to A, and a case where edge label is covered by some other elementof the canvas, as well as some other rare corner cases. Such complexity is required in order to achieve nice looking output regardless of what data the user gives to the program.

This project is purely academic, and if you are not sure what some of the terms used in previous paragraphs mean, I suggest following links to Wikipedia. I daresay that the source code is well-documented, so if you’d like to use some of it in your open-source project, be my guest. In its documentation section, the project has a business analysis and technical documentation written prior to final implementation. The final implementation follows (or at least attempts to follow) the pre-written documentation. I’ve attached quick help guides to most vital elements of the application. These many quick tips are available from within the application via “?” buttons, so you can learn what to do as you go.