[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Proposed changes to SRFI-19
> I prefer time-comparison names without terminal question marks.
> I think these
> (time= t1 t2)
> (time< t1 t2)
> are clearer than these
> (time=? t1 t2)
> (time<? t1 t2)
> The terminal ? is redundant, hence unnecessary clutter.
But so is string=?, char=?, etc. Here I prefer consistency with RnRS
than independent elegance because you don't have to constantly wonder
if you should add the question mark or not. (But I agree that dropping
the ? is more elegant.)
> You may wish to look at the scsh time spec, at the above URL. It has some
> flaws, due to its close binding to the Posix API, but also has some
> nice features. There are two time representations -- time (seconds), and
> date (broken-out time -- y/m/d/h/m/s etc.) The API is quite simple:
> (date) -> the current date (a struct)
> (date tm [tz]) -> the date for time TM in timezone TZ
> (time) -> the current time (an integer)
> (time dt) -> the time for date DT
Except for the names (I would prefer (current-date) and
(current-time)) and that time is represented concretely by an integer,
I like this approach. To me a "time" object is an absolute point on
the time line, and is independent of time zones, etc (and also
independent of relativity but that's another topic...). A "date"
object is really a representation of time that depends on local
context (the time zone, daylight-savings time, etc). I see no problem
in using a "time" object to program a deep-space probe, but would have
a hard time using a "date" object... So I would suggest separating
the two concepts in SRFI-19.