There is no need for me to tell you how great Flycheck is. If you do not trust me, at least trust Mickey Petersen on this.

Since I have been playing around with CHICKEN Scheme for quite some time now, it seemed only natural to wish for on-the-fly syntax checking. Why limit myself to wishing, though? Why do not push it a little further and try to help Flycheck maintainers?

Before starting any coding, I took the time to read the Contributor’s Guide. Like all of Flycheck’s documentation, the Contributor’s Guide is well-written and easy to understand. The guidelines about pull requests and commit messages, in particular, put me on the right track.

I forked the Flycheck’s repository and started going through the code in flycheck.el. The lack of experience brought me to shamelessly copying the Racket checker and trying to figure out how it worked. It was not too hard to understand, but maybe starting with the Perl checker — see here — would have been a better choice. Nonetheless, I stole the idea of having Geiser as a requirement from the Racket checker.

Anyway, it was not time to code yet. I needed to understand if on-the-fly syntax checking in CHICKEN Scheme would be possible at all. Flycheck gives you the power to work with different syntax checkers within the same interface, but I didn’t know of a similar checker for CHICKEN Scheme.

With some help on the #chicken IRC channel and from Vítor De Araújo on Twitter, I was able to devise my first attempt and create the proper pull request.

And that is when the real magic started.

I knew Flycheck maintainers are kind and helpful because I had already had some chances to interact with them, but I cannot remember the last time I worked on something with this kind of patient assistance.

Questions promptly answered, suggestions readily available. My code kept getting better and better. Useless lines were removed, documentation was added and the integration test felt like the right thing to do.

I learnt a lot and could not be happier with the result. I hope I will be able to contribute to Flycheck again. Moreover, I do hope every project I wish to contribute to can follow the Flycheck’s community example.

Now go enjoy your on-the-fly syntax checking with CHICKEN Scheme.