Well, 2 things: first, I meant "currying". second, I found the answer: no.
Under dynamic typing, the reduction steps are:
(\a -> \b -> a) 1 2
(\b -> a) 2 -- the substitution don't occur right away (that would be
lexical scope)
a
?? "a" is not in the environment!!
Sorry for the noise.
PS: In a meta interpreter, lexical scope seems to be actually easier
to implement than dynamic scope.
2009/4/26 Loup Vaillant
Hi, can this code
(\a -> \b -> a) 1 2
eval to normal form in a strict language with dynamic scope?
Thanks, Loup
PS: some context:
I am currently implementing a toy language. The AST is this one:
data whnf = -- Weak Head Normal Form | Unit | Int of int | Bool of bool | Prim of (whnf -> whnf) -- curried | Fun of string * expr -- curried
data expr = | Whnf of whnf | Var of string | App of expr * expr | If of expr * expr * expr
Dynamic typing, dynamic scope, and, as you can see, functions have to be curried. I plan to implement lexical scope.