Hi all,
I'm just trying to write a recursive function that iterates¹ on a string
and I'd like to use pattern matching as in:

let rec iter f s =
   match s with
      | ""  -> unit;
      | c^s1 -> f c; iter f s1;;

but the ^ concatenates 2 strings and not a char with a string and above
all seems to be inadmissible in the patterns.

Does this mean that I can't write a function on strings by pattern
matching or is there something I don't know?²

Thanks for the help
Walter

¹ I know that exists String.iter but I'd like to improve my skill in
   writing functions by using pattern matching
² I read about micmatch but I'd like to avoid non standard packages.
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