RE: [Evolution] Islamic Calendar Support File (Progress!)

["Ray Lee" <ray madrabbit org>]

> > == I, and > == Ali Abdin wrote:

> I create the time_t in the first place by /using/ the tm structure.
> So basically, to create a 'tm' structure from an Islamic date
> should be very simple.

Okay, cool.

> True - but I don't think the calendar-client code is set-up for
> this well (i.e. i don't think it was designed to allow it to work
> with two different calendar formats). So that may take some work.

Agreed, but as soon as you need to deal with two of something, it's just
as easy to deal with a dozen. So this might be a good time to take a quick
peek at the Chinese, Hindu, and other calendars to see what they may need
in terms of support for dates and years, and then find something nice and
abstract that can wrap all of them.

> last_day_of_gregorian_month tells you the number of days (or
> 'size') of the month. I fail to see how time and/or mktime will help
> me in that.

Well, then I'm just not being very clear. Look at this instead, and maybe
it'll explain what I'm trying to say:

        [ray ~]$ cat days.c
        #include <stdio.h>
        #include <time.h>

        int main(int argc, char *argv[]) {
                struct tm tm;
                char buff[10];
                int i;

                for (i=1;i<=12;i++) {
                        memset(&tm,0,sizeof tm);
                        tm.tm_year=atoi(argv[1])-1900;
                        tm.tm_mon=i;
                        tm.tm_mday=0; // 1 is first day, so 0=day before
                        mktime(&tm);  // now the fields are correct
                        strftime(buff,sizeof buff, "%b %d",&tm);
                        printf("%s  ",buff);
                        if (i%6==0) printf("\n");
                }
        }

        [ray ~]$ ./days 2000
        Jan 31  Feb 29  Mar 31  Apr 30  May 31  Jun 30
        Jul 31  Aug 31  Sep 30  Oct 31  Nov 30  Dec 31
        [ray ~]$ ./days 2001
        Jan 31  Feb 28  Mar 31  Apr 30  May 31  Jun 30
        Jul 31  Aug 31  Sep 30  Oct 31  Nov 30  Dec 31
        [ray ~]$

(libc, getting the 2000 leap year problem right for years now...)

[Integration of different calendars into Evolution]
> > Or as above. (Find a nice split point in the code base, define an
> > interface, and populate most of the interface with the
> > existing routines.)
> split point in the code base? sorry I do not understand.

To split the date representation code from the date display code. We don't
care how the date is represented internally, as long as it covers all the
dates and times we're interested in. However, we *do* care about how it's
displayed to the user. So the display code needs to be split away from the
date representation code, and an interface defined, such that any kind of
modern calendar can be used.

Ray Lee / ray madrabbit org ~ rblee impulse net