bug#23486: 25.0.93; Modules: features missing from make_function

[Philipp Stephani]

emacs_env::make_function lacks the following features supported by
`defun':

1. Functions with both optional and rest arguments.
2. Specification of parameter names.
3. Integration with `help-function-arglist'.
4. Specification of interactive forms.
5. Specification of declare forms.
6. Docstrings containing null or non-Unicode characters.

(6) is probably rather unimportant.  (5) is probably not implementable
(would require wrapping `defun', not `lambda').  (1)–(4) are more severe
and quite limit the usefulness of make_function right now; for a
truly generic `defun'-like construct one currently has to eval a `defun'
form wrapping another function.

To solve (1)–(3), I'd propose replacing the "arity" arguments with a
true arglist specification.  This could either be at the C level, e.g.

    ptrdiff_t num_mandatory_args, char** mandatory_arg_names,
    ptrdiff_t num_optional_args, char** optional_arg_names,
    char* rest_arg_name

or by requiring to pass a Lisp argument list.

To solve (4) I'd propose to pass another value for the interactive form,
probably as emacs_value* (to support non-interactive functions).

As an alternative, if people feel this would require too many
parameters, I'd propose reverting the change that adds the documentation
string.  A docstring without arglist is not very useful.  We could also
remove the arity parameters and have the C function check the arity
itself.



In GNU Emacs 25.0.93.5 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2016-04-24 built on localhost
Repository revision: 0cd2e923dba8d8c7128b0c084ce6af22069e8db5
Windowing system distributor 'The X.Org Foundation', version 11.0.11501000
System Description:     Ubuntu 14.04 LTS

Configured using:
 'configure --with-modules'

Configured features:
XPM JPEG TIFF GIF PNG SOUND GSETTINGS NOTIFY FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 MODULES

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns help-mode easymenu
cl-loaddefs pcase cl-lib mail-prsvr mail-utils time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment elisp-mode lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core frame cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese charscript case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer cl-preloaded nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote inotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 88004 8077)
 (symbols 48 19855 0)
 (miscs 40 325 197)
 (strings 32 14723 4466)
 (string-bytes 1 436825)
 (vectors 16 12084)
 (vector-slots 8 438946 3946)
 (floats 8 164 12)
 (intervals 56 202 0)
 (buffers 976 12)
 (heap 1024 36386 931))

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