* cal-x.el/diary-lib.el diary-mode-hook
@ 2008-05-15 9:52 Karl Chen
2008-05-15 14:52 ` Stefan Monnier
0 siblings, 1 reply; 4+ messages in thread
From: Karl Chen @ 2008-05-15 9:52 UTC (permalink / raw
To: emacs-devel
Hi, this is regarding calendar. I experience the symptoms in
Emacs 22.2, and by inspecting CVS HEAD I suspect it is still
affected despite the code having been significantly updated.
emacs -q
(setq diary-display-hook 'fancy-diary-display)
(setq calendar-setup 'one-frame)
(calendar)
A couple places in calendar/*.el seem to assume that
diary-mode-hook is a list of functions, e.g. when it uses ``(memq
'diary-fancy-display diary-display-hook)''.
In my setup I had ``(setq diary-display-hook
'fancy-schedule-display-desk-calendar)'' [instead of add-hook or
``setq .. '(..)''] and this would trigger a type error.
I realize the documentation for diary-display-hook says "list of
functions", but a couple places in the code let-bind
diary-display-hook to non-lists, and the documentation in 22.2 has
sample code with non-lists.
Thanks,
Karl
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: cal-x.el/diary-lib.el diary-mode-hook
2008-05-15 9:52 cal-x.el/diary-lib.el diary-mode-hook Karl Chen
@ 2008-05-15 14:52 ` Stefan Monnier
2008-05-15 19:28 ` Karl Chen
0 siblings, 1 reply; 4+ messages in thread
From: Stefan Monnier @ 2008-05-15 14:52 UTC (permalink / raw
To: Karl Chen; +Cc: emacs-devel
> Hi, this is regarding calendar. I experience the symptoms in
> Emacs 22.2, and by inspecting CVS HEAD I suspect it is still
> affected despite the code having been significantly updated.
> emacs -q
> (setq diary-display-hook 'fancy-diary-display)
> (setq calendar-setup 'one-frame)
> (calendar)
> A couple places in calendar/*.el seem to assume that
> diary-mode-hook is a list of functions, e.g. when it uses ``(memq
> 'diary-fancy-display diary-display-hook)''.
> In my setup I had ``(setq diary-display-hook
> 'fancy-schedule-display-desk-calendar)'' [instead of add-hook or
> ``setq .. '(..)''] and this would trigger a type error.
> I realize the documentation for diary-display-hook says "list of
> functions", but a couple places in the code let-bind
> diary-display-hook to non-lists, and the documentation in 22.2 has
> sample code with non-lists.
Hooks accept either a function or a list of functions, where the former
is only accepted for historical reasons. So all the code that sets
hooks to a single function should be reported as (minor) bugs, and all
the documentation that does that should be reported as (non-minor) bugs.
A quick grep in the EMACS_22_BASE branch disn't show me the sample code
you refer to, so could you please tell us where you found it?
This said, using `memq' on a hook is indeed an error.
Stefan
PS: You should "never" modify a hook with setq, always use `add-hook'.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: cal-x.el/diary-lib.el diary-mode-hook
2008-05-15 14:52 ` Stefan Monnier
@ 2008-05-15 19:28 ` Karl Chen
2008-05-17 20:24 ` Glenn Morris
0 siblings, 1 reply; 4+ messages in thread
From: Karl Chen @ 2008-05-15 19:28 UTC (permalink / raw
To: Stefan Monnier; +Cc: emacs-devel
>>>>> On 2008-05-15 07:52 PDT, Stefan Monnier writes:
>> I realize the documentation for diary-display-hook says
>> "list of functions", but a couple places in the code
>> let-bind diary-display-hook to non-lists, and the
>> documentation in 22.2 has sample code with non-lists.
Stefan> Hooks accept either a function or a list of functions,
Stefan> where the former is only accepted for historical
Stefan> reasons. So all the code that sets hooks to a single
Stefan> function should be reported as (minor) bugs, and all
Stefan> the documentation that does that should be reported as
Stefan> (non-minor) bugs. A quick grep in the EMACS_22_BASE
Stefan> branch disn't show me the sample code you refer to, so
Stefan> could you please tell us where you found it?
Sure.
Emacs 22.2 (Debian)
sample code in docstring:
calendar.el:769: (setq diary-display-hook 'fancy-diary-display)
Let-binds:
appt.el:346: (let* ((diary-display-hook 'appt-make-list)
diary-lib.el:581: (let* ... (diary-display-hook 'ignore)
diary-lib.el:915: (let ((diary-display-hook 'fancy-diary-display))
Stefan> This said, using `memq' on a hook is indeed an error.
Memq on hook:
cal-x.el:90: (if (not (memq 'fancy-diary-display diary-display-hook))
cal-x.el:148: (if (not (memq 'fancy-diary-display diary-display-hook))
Docstring could be tweaked slightly:
diary-lib.el:670: (defun fancy-diary-display ()
diary-lib.el:671: "Prepare a diary buffer with relevant entries in a fancy, noneditable form.
diary-lib.el:672: This function is provided for optional use as the `diary-display-hook'."
Stefan> PS: You should "never" modify a hook with setq, always
Stefan> use `add-hook'.
I see. I think the whole confusion arises because
diary-display-hook doesn't act like a regular hook, where a bunch
of hooks are typically stacked and called sequentially. The
various functions for diary display are really alternates to each
other, not stackable extras. If diary-display-hook already
contains fancy-diary-display, then when add-hook
fancy-schedule-display-desk-calendar has no effect. An nil value
for diary-display-hook also has different semantics than for
regular hooks. Perhaps it should have been called
"diary-display-function" to begin with, though there was probably
a reason for converting it into a list-of-functions hook other
than just its name.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2008-05-17 20:24 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2008-05-15 9:52 cal-x.el/diary-lib.el diary-mode-hook Karl Chen
2008-05-15 14:52 ` Stefan Monnier
2008-05-15 19:28 ` Karl Chen
2008-05-17 20:24 ` Glenn Morris
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