shapeless
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milessabin
Add variants of Fn{To,From}Product which are parametric in the result type
See this gist for a motivating example.
A result type parametric Fn{To,From}Product would allow us to constrain the shape of the arguments to an arbitrary arity function type without having to commit a particular result type. In the example shown we've worked around this by constraining an HList argument L to a Function1 and then have an implicit conversion from an arbitrary arity function to that L => R. This only works if the type of the function is fully known, hence the type annotations on the function's arguments.
@milessabin do you mean something like FnGeneric in this PR: typelevel/kittens#223
Do you think it makes sense to contribute it to shapeless instead?
Honestly I have no recollection of what this issue is about and the description and the gist are leaving me none the wiser.
I don't have any strong feelings about whether that PR belongs in kittens or here.
I don't have any strong feelings about whether that PR belongs in kittens or here.
Me neither. Then I would keep it in kittens.
If anyone needs this they can use the version from Kittens: https://github.com/typelevel/kittens/pull/223