bug#13536: 24.2; Patterns in `diary-european-date-forms' NOT mutually exclusive -- incl. suggested Fix

bug#13536: 24.2; Patterns in `diary-european-date-forms' NOT mutually exclusive -- incl. suggested Fix

[Andreas Merziger]

To reproduce the bug start with

emacs -Q

Contents of ~/diary are the following five lines:
23 Jan 10:00 Test-Entry 1
23 Jan 10pm Test-Entry 2
23 Jan 10am Test-Entry 3
23 Jan 10Pm Test-Entry 4
23 Jan 10Am Test-Entry 5

1.) Start the calendar:

M-x calendar

2.) Set calendar-date-style to 'european

M-x calendar-set-date-style

Choose 'european.

3.) In *Calendar* - buffer go to date:

 January, 23 of year 10

4.) Type key `d' to show the diary for that date

UNEXPECTEDLY, the buffer `Fancy Diary Entries' looks like this:

Saturday, 23 January 10
=======================
10:00 Test-Entry 1
10pm Test-Entry 2
10am Test-Entry 3
10Pm Test-Entry 4
10Am Test-Entry 5
00 Test-Entry 1
m Test-Entry 2
m Test-Entry 3
m Test-Entry 4
m Test-Entry 5


The first five line are the expected ones - the last five lines appear due to the
fact, that the elements of the list `diary-european-date-forms' are NOT
mutually exclusive, as they should as required by the documentation.

--- End of Bug description ---

SUGGESTED FIX:

In File PATH-TO-EMACS/lisp/calendar/calendar.el 
do the following:

(defcustom diary-european-date-forms
  '((day "/" month "[^/0-9]")
    (day "/" month "/" year "[^0-9]")
    (backup day " *" monthname"\\W+\\<\\([^*0-9]\\|\\([0-9]+[:aApP]\\)\\)")
;;--------------------------------------------------------------
;; (day " *" monthname " *" year "[^0-9]")  (not restrictive enough)
   (day " *" monthname " *" year "[^0-9:aApP]") ;; (suggested fix)
;;--------------------------------------^^^^^------------------- 
;; Include letters a,A,p,P and colon here
;;
    (dayname "\\W"))
  "List of pseudo-patterns describing the European style of dates.
The defaults are: DAY/MONTH; DAY/MONTH/YEAR; DAY MONTHNAME;
DAY MONTHNAME YEAR; DAYNAME.  Normally you should not customize this, but
`diary-date-forms' (which see)."
  :type '(repeat (choice (cons :tag "Backup"
                               :value (backup . nil)
                               (const backup)
                               (repeat (list :inline t :format "%v"
                                             (symbol :tag "Keyword")
                                             (choice symbol regexp))))
                         (repeat (list :inline t :format "%v"
                                       (symbol :tag "Keyword")
                                       (choice symbol regexp)))))
  :group 'diary)

After this change I could not observe this unexpected behaviour anymore.

COMMENT:
This misbehaviour is not just a matter of sophistry.
I'm trying to develop a contribution to emacs calendar/diary
which allows a form of natural (automated) archiving of outdatet diary entries, this
way trying to avoid that the diary file grows unnecessarily large over
time. (Any hints, ideas, minimal requirements on this welcome :-))

Matching of diary entries is much harder, if these date-forms are NOT
mutually exclusive.

So please consider fixing that the suggested (or any other) way.

Thanks in advance!

bug#13536: 24.2; Patterns in `diary-european-date-forms' NOT mutually exclusive -- incl. suggested Fix

[Lars Ingebrigtsen]

Andreas Merziger <andreas.merziger@online.de> writes:

> To reproduce the bug start with
>
> emacs -Q
>
> Contents of ~/diary are the following five lines:
> 23 Jan 10:00 Test-Entry 1
> 23 Jan 10pm Test-Entry 2
> 23 Jan 10am Test-Entry 3
> 23 Jan 10Pm Test-Entry 4
> 23 Jan 10Am Test-Entry 5
>
> 1.) Start the calendar:
>
> M-x calendar
>
> 2.) Set calendar-date-style to 'european
>
> M-x calendar-set-date-style
>
> Choose 'european.

(I'm going through old bug reports that have unfortunately gotten no
responses yet.)

I don't use Calendar that much, but I don't quite understand this use
case.  If you have "10am" in your diary file, and then you set the date
style to `european', then surely that diary file will be invalid?
"10am" isn't a valid `european' way to specify a time, I think?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#13536: 24.2; Patterns in `diary-european-date-forms' NOT mutually exclusive -- incl. suggested Fix

[Lars Ingebrigtsen]

The mail bounced, so I'm closing this bug report.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#13536: 24.2; Patterns in `diary-european-date-forms' NOT mutually exclusive -- incl. suggested Fix

[Glenn Morris]

Lars Ingebrigtsen wrote:

> I don't use Calendar that much, but I don't quite understand this use
> case.  If you have "10am" in your diary file, and then you set the date
> style to `european', then surely that diary file will be invalid?
> "10am" isn't a valid `european' way to specify a time, I think?

The default value of diary-european-date-forms obviously tries to
support times of the form "10:00", "10am", "10AM", "10pm", "10PM".

The various elements of said form should be mutually exclusive but
aren't, as the OP demonstrates.

This seemed like a valid bug report to me, but I never cared enough to
do anything about it.

IMO applying the suggested fix or leaving it open would be better than
closing it due to a bouncing email.

bug#13536: 24.2; Patterns in `diary-european-date-forms' NOT mutually exclusive -- incl. suggested Fix

[Lars Ingebrigtsen]

Glenn Morris <rgm@gnu.org> writes:

> The default value of diary-european-date-forms obviously tries to
> support times of the form "10:00", "10am", "10AM", "10pm", "10PM".
>
> The various elements of said form should be mutually exclusive but
> aren't, as the OP demonstrates.
>
> This seemed like a valid bug report to me, but I never cared enough to
> do anything about it.

Oh, I missed that bit in the value above ("backup day") which indeed
supports AM/PM.

So I've applied the change now.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no