[Haskell-cafe] Fwd: Pointers by using functions

[Holden Lee]

What is the best way to implement data structures that use pointers in
Haskell?

My first thought is as follows. Suppose for simplicity the labels are just
integers, and each object need to point to one other one. I would have a

getObject:: Int -> a
f:: Int -> Int

But I don't understand how Haskell maintains functions in memory, and in
particular whether lookup/update is efficient. So suppose I define a f

f x = case x of
 1 -> 2
 2 -> 3
.... (etc.)

Q: if there are n entries here, how long does looking up (f m) take?

Suppose later I update, with something like this:

update::Int->Int->(Int->Int)->(Int->Int)
update x y f z = (if z==x then y else f x)

Q: how is "update x y f" maintained?

Is using a f::Int->Int like using a pointer in terms of time complexity,
and if not, what data structure should I use instead?

Thanks,
Holden
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