Declaring primitive function types

[Andrea Corallo <acorallo@gnu.org>]

Hi all,

yesterday night I toyed with some code (scratch/func-type-decls) to move
out the type declaration of primitive functions from
'comp-known-type-specifiers' and move them to where actually functions
are defined.

In order to do that I added an optional argument to the DEFUN macro.

So to get practical 'arrayp' definition goes from:

DEFUN ("arrayp", Farrayp, Sarrayp, 1, 1, 0,
       doc: /* Return t if OBJECT is an array (string or vector).  */)
  (Lisp_Object object)
{
  if (ARRAYP (object))
    return Qt;
  return Qnil;
}

to:

DEFUN ("arrayp", Farrayp, Sarrayp, 1, 1, 0,
       doc: /* Return t if OBJECT is an array (string or vector).  */,
       (function (t) boolean))
  (Lisp_Object object)
{
  if (ARRAYP (object))
    return Qt;
  return Qnil;
}

I guess another option would have been having the type in the doc
argument (as for attributes) and have something like:

DEFUN ("arrayp", Farrayp, Sarrayp, 1, 1, 0,
       doc: /* Return t if OBJECT is an array (string or vector).  */
       type: (function (t) boolean))
  (Lisp_Object object)
{
  if (ARRAYP (object))
    return Qt;
  return Qnil;
}

This would complexify a little things as we'd need 'make-docfile' to
parse it and generate something somewhere that we read afterwards.

I like the solution of the prototype for its simplicity but maybe people
find the last one is more aesthetic?  Also I've the impression that
'make-docfile' was used so far only for problems that were not solvable
with just the DEFUN expansion.

Opinions?

Thanks!

  Andrea

PS for lisp functions I'm about to open another thread as I think will
be more efficient to be discuss the two separately