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* bug#58563: 29.0.50; Generic functions and advertised-calling-convention
@ 2022-10-16 10:24 Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
  2022-10-16 10:33 ` Lars Ingebrigtsen
                   ` (2 more replies)
  0 siblings, 3 replies; 14+ messages in thread
From: Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors @ 2022-10-16 10:24 UTC (permalink / raw)
  To: 58563; +Cc: Stefan Monnier

Further to https://bugs.gnu.org/58531#25, generic functions do not
currently support advertised-calling-convention very well (or vice
versa).

For example, starting with:

  (cl-defgeneric my-foo (x &optional _y)
    "Frobnicate X."
    (declare (advertised-calling-convention (x) "29.1"))
    x)

Any code that calls my-foo with two arguments correctly gives rise to a
warning during byte-compilation.

C-h f also shows the expected arglist, but not for methods:

  my-foo is a Lisp closure.
  (my-foo X)
  Frobnicate X.
  This is a generic function.
  Implementations:
  (my-foo X &optional _Y)
  Undocumented

More importantly, if we now do:

  (cl-defmethod my-foo ((x symbol) &optional _y)
    "Frobnicate X the symbol."
    (declare (advertised-calling-convention (x) "29.1"))
    x)

Then my-foo's symbol-function is overwritten and its entry in
advertised-signature-table is no longer found, so byte-compilation no
longer warns about incorrect usage, and C-h f regresses to displaying:

  my-foo is a byte-compiled Lisp function.
  (my-foo X &optional Y)
  Frobnicate X.
  This is a generic function.
  Implementations:
  (my-foo (X symbol) &optional _Y)
  Frobnicate X the symbol.
  (my-foo X &optional _Y)
  Undocumented

Note that, unlike with cl-defgeneric, the declare form in cl-defmethod
does not expand to a call to set-advertised-calling-convention.  If
set-advertised-calling-convention is called after the cl-defmethod, then
the advertised-calling-convention is preserved (or rather reinstated),
but only until the next cl-defmethod is defined (which could happen in
third-party code).

I guess either advertised-signature-table should be extended to allow
for the nature of generic functions, or cl-defmethod should be taught to
preserve such function properties (or both).

I wonder if cl-defgeneric should be the single source of this function
property, or whether any cl-defmethod should be able to overload it.
Thoughts?

Thanks,

-- 
Basil

In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.16.0, Xaw3d scroll bars) of 2022-10-16 built on tia
Repository revision: 07222447b6c9e75b713fe3b3954952fbb0e40c71
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Debian GNU/Linux bookworm/sid





^ permalink raw reply	[flat|nested] 14+ messages in thread

end of thread, other threads:[~2022-10-26 14:45 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-10-16 10:24 bug#58563: 29.0.50; Generic functions and advertised-calling-convention Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-16 10:33 ` Lars Ingebrigtsen
2022-10-16 14:26   ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-16 14:27     ` Lars Ingebrigtsen
2022-10-16 14:49       ` Lars Ingebrigtsen
2022-10-16 15:08         ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-16 15:16           ` Lars Ingebrigtsen
2022-10-16 15:35             ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-16 11:10 ` Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-16 16:05 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-23 17:15   ` Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-24 19:50     ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-26 13:51       ` Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-26 14:45         ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors

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