README.md

This learning exercise has come to an end. We are continuing work in this area here

Derivatives for Regular Expressions with Coq

This repo reexamines a few papers on regular expressions using Coq as a learning exercise. We try to prove some things that are mentioned in the papers as a way to teach ourselves some Coq.

• Brzozowski In this folder we explore proving theorems from the original paper Derivatives of Regular Expressions - Janusz A Brzozowski We have retyped and modified it a bit to aid readability.
• Coinduction In this folder we explore using coinduction to prove regular expressions are equivalent.
• Reexamined In this folder we explore a modern version of derivatives defined in the paper Regular-expression derivatives reexamined This paper is a great introduction to using derivatives for regular expressions, since it has been not only been updated, but is also one of the easier papers to read.
• CoqStock standard library.

Background

Brzozowski's Derivatives of Regular Expressions

If you are unfamiliar with Brzozowski's Derivatives you can watch this video.

Setup

1. Install Coq 8.13.0
2. Remember to set coq in your PATH. For example, in your ~/.bash_profile add PATH="/Applications/CoqIDE_8.13.0.app/Contents/Resources/bin/:${PATH}" and run $ source ~/.bash_profile.
3. Run make in this folder.

Note:

• make cleanall cleans all files even .aux files.

Contributing

Please read the contributing guidelines. They are short and shouldn't be surprising.

Regenerate Makefile

Coq version upgrade requires regenerating the Makefile with the following command:

$ coq_makefile -f _CoqProject -o Makefile

Pair Programming

We used to pair program. The schedule was posted as meetups events on meetup.com