Re: [Caml-list] a question about Ocaml toplevel behavior

["Matej Košík" <mail@matej-kosik.net>]

Hi Nicolás,

Thank you for the reply.

On 03/11/18 16:06, Nicolás Ojeda Bär wrote:
> Hello Matej,
> 
> My understanding is that the compiler will delay opening a .cmi file
> until absolutely necessary.> Since it does not need to look into Location in order to compile the
> given phrase, the .cmi is not opened and the type Location.t remains
> abstract. But if you give the compiler an excuse to open location.cmi
> then the definition of the type Location.t will become known to the
> compiler and the toplevel will be able to print the values concretely.
I see some of the disadvantages of this behavior:

  (0) I have lost time wondering why things are printed as "<abstr>" instead of the real thing.

  (1) "<abstr>" may (confusingly) mean something else than "a value of an abstract type".
      It may mean that "toplevel has find an excuse not to load a relevant *.cmi file some so it does not know (yet) how to print a given value.
      (this is very unintuitive)

  (2) #install_printer directive may have no effect if toplevel has find an excuse not to load relevant *.cmi file.
      (this is very unintuitive)

Was this done on purpose? What do we gain from this behavior?
(considering that computer time (as opposed to human time) has ~zero value).