Clojure’s instaparse TI-style math interpreter

There aren’t too many examples of Clojure’s instaparse use out there, so if you’re working on parsing a little language of your own, I hope this might come in handy.

I’ve been working on a little interpreter for some internal stuff part of the Front Row stack, mainly for validating student answers in the more complex middle school math domains. The interpreting the answer becomes pretty much mandatory for validating things like equivalence of two polynomials. This is what came out from the early efforts.

The EBNF grammar itself can be found here, the implementation of the parser is here (still blows my mind it’s under 50 lines), and the tests are all here. Wouldn’t have touched this with a ten foot pole without testing every single incremental addition.

A couple of resources I found useful, in addition to instaparse’s official docs:

The author of instaparse himself was also generous with a few tips on the library’s Google Groups.

Clojure’s instaparse TI-style math interpreter

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