On 21/12/2011 9:41 PM, Jonathan M Davis wrote:
Okay. At the moment, the time point types in std.datetime have functions for
converting to and from strings of standard formats but not custom formats, so
functions for that need to be added. I've come up with a proposal for how
they're going to work and would like some feedback on it.
Originally, I was going to make them work like strftime and strptime, since it
was my understanding that those functions were fairly standard among various
programming languags. And it _does_ look like a variety of programming
languages have something similar (Java, Ruby, Python, etc.), but the exact set
of flags that they use is not standard, so there _isn't_ really a standard to
follow, just similar functions across a variety of programming languages. And
honestly, strftime and strptime aren't very good. They're fairly limited IMHO,
and the choice of flags is fairly arbitrary, so it seems like a good idea to
Every language seems to force you memorize a bunch of format strings for
different toString functions, which is quite annoying. I highly doubt
I'm the only person who has to look up the format strings every single
time I want to use a custom toString (besides an obvious one like YYYY).
It would be nice if D did better in this regard. Something taking
advantage of enums, such as 'time.toCustomString!(Year, ", ", LongHour,
":", LongMinute, " ", AMPM)'. The problem with that particular example,
is that it's... quite ugly. And bloated. Perhaps there would be a way to
make it not quite so bloated however, while still retaining the
simplicity of compile-time enums.
Perhaps this doesn't matter so much in D though, given that template
arguments are passed in and thus can be evaluated at compile-time. I
definitely like the current approach shown in docs, but it's still
painful to try and figure out something like
assert(st.toCustomString!"%4yplus%04+Y-%emon-%02D%02H:%02m:%02s%f%tz"()
== "2010-Jul-04 07:06:12").
