Re: [Caml-list] Newbie question: semantics of 'mutable' in relation to deep / shallow copying of CAML values.

[Alain Frisch <frisch@clipper.ens.fr>]

On Thu, 22 Nov 2001, Gerard Murphy wrote:

> #       let value2 = value1;;

This is just a binding, no copy is involved: value1 and value2
simply denotes the same value. There are several methods to
create shallow copies of values:
- for objects: use Oo.copy or the {< >} notation
- for records: use the { r with ...} notation (you have to make
  at least one field explicit !)
- for everything except objets, you can also use Obj.dup, but
  you are not encouraged to do so !

To create deep copies, the only generic method, AFAIK, it to
marshal/unmarshal values:

let deep (x : 'a) : 'a = Marshal.from_string (Marshal.to_string x [Marshal.Closures]) 0;;

(add Marshal.No_sharing to the list if you don't want to keep sharing
inside the value)

I never felt the need for such an operation in OCaml, though.

-- 
  Alain

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