Re: [PATCH] Reimplement module functions

[Eli Zaretskii <eliz@gnu.org>]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Sat, 13 May 2017 16:44:08 +0200
> Cc: Philipp Stephani <phst@google.com>
> 
> Instead of a lambda, create a new type containing all data required to
> call the function, and support it in the evaluator.  Because this type
> now also needs to store the function documentation, it is too big for
> Lisp_Misc; use a pseudovector instead.  That also has the nice benefit
> that we don't have to add special support to the garbage collector.

Thanks.

> +#ifdef HAVE_MODULES
> +  else if (MODULE_FUNCTIONP (fun))
> +    doc = XMODULE_FUNCTION (fun)->documentation;
> +#endif

I wonder whether it would be cleaner to have MODULE_FUNCTIONP defined
even when HAVE_MODULES is not: it looks like it could save us quite a
few #ifdef's.

> -DEFUN ("internal--module-call", Finternal_module_call, Sinternal_module_call, 1, MANY, 0,
> -       doc: /* Internal function to call a module function.
> -ENVOBJ is a save pointer to a module_fun_env structure.
> -ARGLIST is a list of arguments passed to SUBRPTR.
> -usage: (module-call ENVOBJ &rest ARGLIST)   */)
> -  (ptrdiff_t nargs, Lisp_Object *arglist)
> +Lisp_Object
> +funcall_module (const struct Lisp_Module_Function *const envptr,
> +                ptrdiff_t nargs, Lisp_Object *arglist)
>  {

I don't think we can simply remove a function that was already present
in one or more Emacs releases.  We need to provide a backward
compatibility layer, and definitely also mention this in NEWS.