Hello All I am trying to flatten a list in Ocaml. I am a newbie so please pardon me if my mistake is dumb
So for example, if input is [[1];[2;3];[4]] I should end up with [1;2;3;4].
The idea I am trying to use is as follows Iterate through the list from the right (Using fold_right) with accumaltor = [] The pseudo code is as follows
func flatten(list, accumalator)
For each item from right to left in list
If Item is a scalar then n :: accumalator
Else fi Item is a list of form head :: tail then
head :: flatten (tail, accumalator).
I think that theoretically the algorithm is correct, but please let me know if you disagree.
Now to my OCaml code to implement this algorithm
let rec flatten acc x =
match x with
n -> n :: acc
| [x] -> x :: acc
| head :: remainder ->
head :: ( my_flat acc remainder )
and my_flat = List.fold_right flatten
;;
my_flat [] [[1];[2;3];[4]]
The Error I get is the following Error: This expression has type 'a but an expression was expected of type 'a list
The error occurs on the line that reads head :: ( my_flat acc remainder ) in the last pattern in the match statement
Any help is appreciated.