[Caml-list] re: help with ocaml

[Caml-list] re: help with ocaml

[Bauer, Robert]

Hi,

I have a little definition below written in ocaml.  My problem is that when
I define the class
lattice_point, I would have liked to specify the types of the parameters;
however, when I do so
I get an error - instead, I have to specify the types of the class's
attributes.  I am hoping that
someone can shed some light on this.

Also, I find that if try to use any capitalized variables, I get interesting
errors - for
example if I try let XYZ_ZYX = (false, false);; I get an error, whereas let
xyz_zyx = (false, false);;
works just fine. Or more simply, let XYZ = (false, false);; fails.  Again, I
am hoping for an explanation.

class lattice_point left right =
 object
  val mutable l:bool = left
  val mutable r:bool = right

  method get_l = l
  method get_r = r
end;;

let top_def = new lattice_point false false;;

Thanks.
-------------------
Bug reports: http://caml.inria.fr/bin/caml-bugs  FAQ: http://caml.inria.fr/FAQ/
To unsubscribe, mail caml-list-request@inria.fr  Archives: http://caml.inria.fr

Re: [Caml-list] re: help with ocaml

[Jean-Christophe Filliatre]

Bauer, Robert writes:
 > 
 > Also, I find that if try to use any capitalized variables, I get interesting
 > errors - for
 > example if I try let XYZ_ZYX = (false, false);; I get an error, whereas let
 > xyz_zyx = (false, false);;
 > works just fine. Or more simply, let XYZ = (false, false);; fails.  Again, I
 > am hoping for an explanation.

Ocaml distinguishes between capitalized and uncapitalized identifiers.
The former are used for  constructors, exceptions and modules, and the
latter for other kinds (values, types, etc.)

This helps  avoiding trivial mistakes,  like mispelling the name  of a
constructor (which  would therefore be  understood as a  variable). It
also  helps  when  reading  third-party  code, since  you  can  easily
discriminate between constructors and functions in an application, for
instance.

There is a page of ocaml reference manual about names:

      http://caml.inria.fr/ocaml/htmlman/manual010.html

Sincerely,
-- 
Jean-Christophe Filliatre
  mailto:Jean-Christophe.Filliatre@lri.fr
  http://www.lri.fr/~filliatr
-------------------
Bug reports: http://caml.inria.fr/bin/caml-bugs  FAQ: http://caml.inria.fr/FAQ/
To unsubscribe, mail caml-list-request@inria.fr  Archives: http://caml.inria.fr