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Re: BASIC oddity?

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Alan Adams wrote:
> Jean-Michel wrote:
>> druck wrote:
>>> But anyway this highlights the lack of date and time manipulation SWIs
>>> in RISC OS. The only things you can do with a 5 byte time is convert it
>>> to or from a string.
>> SWI Territory_ConvertTimeToOrdinals
>> return an integers block with centisecond, second, minute, hour, etc

And the other variants, now subsumed into Territory_ConvertTimeFormats 
in RO5.

The Territory SWIs are not very friendly. ;-)

> And it  would be possible to do date-based arithmetic using this. Messy in
> the general case, because of varying month lengths, and leap years. For
> just elapsed time within a day or two, not too bad.

You also have 'Day of Week' (DOW) and 'Day of Year' (DOY) which might be 
useful, but for extended periods you need the Julian Day Number (JDN). 
There is a suitable algorithm on the Wikipedia page.

> I did wonder whether switching to BASIC VI and putting the data into
> floats would be a workaround. The floats in BASIC VI have more than 40
> bits of precision.

With care I have used BASIC V floats to represent unsigned integer 
values greater than &7FFFFFFF, to do things like DIV and MOD in special 
cases. There is no universal way to do this, though.

In addition, a BASIC V float is adequate to hold a 5-byte UTC value. You 
cannot do anything with it directly, but the '|' indirection operator 
can copy it back into a buffer to be manipulated.

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BASIC oddity? Alan Adams <alan@adamshome.org.uk> - 2020-01-03 17:16 +0000
  Re: BASIC oddity? Martin <News03@avisoft.f9.co.uk> - 2020-01-03 19:31 +0000
    Re: BASIC oddity? druck <news@druck.org.uk> - 2020-01-03 21:00 +0000
      Re: BASIC oddity? Alan Adams <alan@adamshome.org.uk> - 2020-01-03 22:26 +0000
        Re: BASIC oddity? Steve Drain <steve@kappa.me.uk> - 2020-01-04 10:40 +0000
          Re: BASIC oddity? Martin <News03@avisoft.f9.co.uk> - 2020-01-04 16:08 +0000
            Re: BASIC oddity? Alan Adams <alan@adamshome.org.uk> - 2020-01-04 16:22 +0000
              Re: BASIC oddity? David Higton <dave@davehigton.me.uk> - 2020-01-04 17:24 +0000
                Re: BASIC oddity? Alan Adams <alan@adamshome.org.uk> - 2020-01-04 18:47 +0000
                Re: BASIC oddity? Matthew Phillips <spam2011m@yahoo.co.uk> - 2020-01-06 08:58 +0000
                Re: BASIC oddity? David Higton <dave@davehigton.me.uk> - 2020-01-06 16:20 +0000
                Re: BASIC oddity? Matthew Phillips <spam2011m@yahoo.co.uk> - 2020-01-07 08:49 +0000
                Re: BASIC oddity? Martin <News03@avisoft.f9.co.uk> - 2020-01-07 11:20 +0000
                Re: BASIC oddity? David Higton <dave@davehigton.me.uk> - 2020-01-07 15:05 +0000
                Re: BASIC oddity? Matthew Phillips <spam2011m@yahoo.co.uk> - 2020-01-08 08:23 +0000
                Re: BASIC oddity? Alan Adams <alan@adamshome.org.uk> - 2020-01-08 10:26 +0000
                Re: BASIC oddity? druck <news@druck.org.uk> - 2020-01-08 21:02 +0000
                Re: BASIC oddity? Richard Ashbery <basura@invalid.addr.uk> - 2020-01-09 12:53 +0000
                Re: BASIC oddity? Steve Fryatt <news@stevefryatt.org.uk> - 2020-01-09 23:16 +0000
                Re: BASIC oddity? Steve Fryatt <news@stevefryatt.org.uk> - 2020-01-08 22:35 +0000
                Re: BASIC oddity? Martin <News03@avisoft.f9.co.uk> - 2020-01-08 23:51 +0000
          Re: BASIC oddity? Steve Drain <steve@kappa.me.uk> - 2020-01-10 11:30 +0000
            Re: BASIC oddity? Alan Adams <alan@adamshome.org.uk> - 2020-01-10 12:38 +0000
      Re: BASIC oddity? Jean-Michel <jmc.bruck@orange.fr> - 2020-01-06 20:39 +0100
        Re: BASIC oddity? Alan Adams <alan@adamshome.org.uk> - 2020-01-06 21:13 +0000
          Re: BASIC oddity? Steve Drain <steve@kappa.me.uk> - 2020-01-08 12:46 +0000

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