Cannot create apply function with static language?

Question

I have read that with a statically typed language like Scala or Haskell there is no way to create or provide a Lisp apply function:

(apply #\'+ (lis         


        

Answer 1

A list in Haskell can only store values of one type, so you couldn't do funny stuff like (apply substring ["Foo",2,3]). Neither does Haskell have variadic functions, so (+) can only ever take two arguments.

There is a $ function in Haskell:

($)                     :: (a -> b) -> a -> b
f $ x                   =  f x

But that's only really useful because it has very low precedence, or as passing around HOFs.

I imagine you might be able to do something like this using tuple types and fundeps though?

class Apply f tt vt | f -> tt, f -> vt where
  apply :: f -> tt -> vt

instance Apply (a -> r) a r where
  apply f t = f t

instance Apply (a1 -> a2 -> r) (a1,a2) r where
  apply f (t1,t2) = f t1 t2

instance Apply (a1 -> a2 -> a3 -> r) (a1,a2,a3) r where
  apply f (t1,t2,t3) = f t1 t2 t3

I guess that's a sort of 'uncurryN', isn't it?

Edit: this doesn't actually compile; superseded by @FUZxxl's answer.