[Haskell-cafe] GHC including System.Time but not Data.Time?

John Goerzen jgoerzen at complete.org
Tue Apr 14 12:44:12 EDT 2009

Hi folks,

Apologies in advance because this sounds rantish...

So I went to my friendly API reference at
http://www.haskell.org/ghc/docs/latest/html/libraries/index.html and
noticed that I couldn't find Data.Time there anymore.  Though it was
still at

After some checking on IRC, apparently this is on purpose.

I find it *incredibly* annoying, and leaves us with the following
unfortunate set of circumstances:

1) GHC ships with NO way to do date/time calculations in the preferred
   way (Data.Time)

2) GHC's docs reference only the obsolete (System.Time) way of doing
   things, with no reference to the preferred way.

3) I can't tell people to just install GHC and expect them to be able
   to perform date & time calculations the preferred way.  Just about EVERY other
   language (C, Perl, Java, Python, etc.) come with this as part of
   the base install.

4) I can't update all my apps to use Data.Time without worrying about
   Yet Another Dependency.

5) Result: black eye on us.

As I saw on IRC:

<quicksilver> the system isn't supposed to work out the box.
<quicksilver> the haskell platform is supposed to work out of the box.
<quicksilver> (shame it doesn't exist)

Which is a fine goal, but until then, pretty please don't go dropping
Data.Time out of GHC.

I understand the goal of removing stuff from GHC, but the practical
implications can be rather annoying.

-- John

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