Ocaml: using list.length

Question

I am trying to find the length of a list in ocaml.

I call a function first called

> let get_list_length e in   
> print_list_length out x

the actual code in get_list_length is where I am confused. The "e" is a list of "commands" and I want to find the length of all the "commands".

let get_list_length(e:values) : unit =
match e with
let x = list.length(e);;

So my e is the list of "commands" which are a bunch of values specified in my grammar file. I am confused about how to get the length of the list since e is a list of values and I want the length of that list.

Any help would be appreciated.

Solution

To get the length of a list is simple:

List.length my_list

Your get_list_length function can be as simple as:

let get_list_length e = List.length e

or more simply:

let get_list_length = List.length

As you currently have defined it, get_list_length returns type unit so you won't get anything useful from it. You are also using match incorrectly, it's usually used like this:

match e with something -> do something
| something_else -> do something_else