OCaml - Pattern matching with list reference in a tuple

Question

is there a cleaner way of doing this? I'm trying to do pattern matching of a

(a' option * (char * nodeType) list ref

the only way I found was doing this :

match a with
| _, l -> match !l with
  | (c, n)::t -> doSomething 

Wouldn't there be a way to match a with something else like ...

match a with
| _, ref (c,n)::t -> doSomething

... or something similar? In this example it doesn't look heavy to just do another match with, but in the real case it can somewhat be...

Thanks for your answers.

Answer 1

The ref type is defined as a record with a mutable field:

type 'a ref = {
    mutable contents : 'a;
}

This means that you can pattern match against it using record syntax like this:

match a with
| _, { contents = (c,n)::t } -> doSomething

Answer 2

In OCaml a ref is secretly a record with a mutable field named contents.

match a with
| _, { contents = (c, n) :: t } -> (* Do something *)