Clojurians Log v2

Sorry for the late reply. I will hopefully be able to answer this thoroughly today. It is actually something that comes up quite often so, I plan on adding some examples to the cookbook. Optionality is a little difficult just because it is context sensitive. The easiest (but often times not scalable) answer is to make multiple patterns that match with or with out it. Like I said, I should have an example later today.

@pbaille Here is one way: https://github.com/timothypratley/justice/blob/master/src/justice/defn.cljc

FWIW If you compare it with the “spec driven approach” linked in the comment I think Meander is way more expressive 🙂

note that the way I emulated “optional” was to use a memory variable constrained to contain 1 or 0 elements

I wish Meander had a built in operator for optional (hint hint @noprompt)

@timothypratley The memory variable trick works too. I didn’t use it in the example. 🙂

I tried to hack on in one time. But the compiler depends on the length of a pattern quite often to be able to do things intelligently. I found myself running into trouble because of that.

Also as a side topic; you can use tools analyzer to parse/emit normalized versions then match with meander to remove most optionality (happy to share examples on that too if interesting).