Yeah, I'm not really getting the single-assignment bit. That kind of thing makes me think about effect systems and linear types instead... In any case, let ...

Yeah, I'm not really getting the single-assignment bit. That kind of thing makes me think about effect systems and linear types instead... In any case, let ... is basically syntactic sugar for lambdas. let x = a in b is equivalent to (\x -> b)(a) Other than aesthetics, the only reason to have a separate "let" syntax is to tell the typechecker that a function can be polymorphic.