On Sun, May 11, 2008 at 9:06 PM, Ashley Yakeley
I've implemented 'ParseTime' and 'Read' instances for 'AbsoluteTime'. Before submitting a patch I want to confirm with you that they belong in 'Data.Time.Format.Parse' as opposed to 'Data.Time.Clock.TAI'. Is this correct?
I'm not sure if it matters, since it is instances rather than new exported symbols, and anyone using those instances must have both AbsoluteTime and ParseTime in scope already.
True for the 'ParseTime' instance but not necessarily so for the 'Read' instance. I recall being rather confused at first that 'UTCTime' and its 'Show' and 'Read' instances were in three different modules, but perhaps it has to be that was due to dependencies. This doesn't seem to be the case with 'AbsoluteTime' so since you don't seems to have any preference I'll put them all in 'Data.Time.Clock.TAI'.
I'm doing work on additional time coordinates of interest to e.g. astrodynamicists. In particular Terrestrial Time (TT = TAI + 32.184 seconds, previously known as Terrestrial Dynamical Time or TDT) and perhaps Geocentric Coordinate Time (TCG) and others. Would you be interested in receiving patches with these rather esoteric time coordinates? If not I'll release them in a new "time-astro" package.
Are you going to create a new type for TT?
TT is isomorphic to TAI in the category of measurements. I've generally tried to avoid separate types for isomorphic measurements. That's why it's called AbsoluteTime rather than TAITime...
I did already create a new type for TT. However, what you are saying makes sense too (I've been wondering about the 'AbsoluteTime' name). I'm not sure that how to best handle parsing and formatting of TT without another type though... I'll give it some thought. Hmm, I realize I might also have to reconsider my 'ParseTime' instance for 'AbsoluteTime' before I submit that patch... Thanks, Bjorn