How does Djinn work?

Question

OK, so I realise that I will probably regret this for the rest of my life, but... How does Djinn actually work?

The documentation says that it uses an algorithm whic

Answer 1

Perhaps I'm looking at this all wrong. Perhaps all this formal logic stuff is just a distraction. Rather than staring at the deduction rules for LJT or whatever, maybe the thing I should be doing is looking at Haskell.

There are, what, 6 possible kinds of expression in Haskell? And each one places different type constraints on the variables it uses, right? So, maybe I just generate one new variable for each argument in the function's type, and start seeing what expressions I can construct.

It's not even like you have to generate all possible expressions in a brute-force search. If none of your arguments have function types, there's no point trying function applications. If all of your arguments are polymorphic type variables, case expressions aren't going to help you. And so on. The types available tell you which sorts of expressions might work.

Things get a bit more interesting if you're allowing your code to call existing top-level functions. Aside from the amusing scoping problems with polymorphic types, there's the question of figuring out which functions will or won't help you.

Clearly I will have to go away and think about this for a while...