[Haskell-cafe] When does the UNPACK pragma work?

[Eugene Kirpichov]

Oh, I see, thanks!

So then, I guess, the solution would be to use a fixed-precision integer
type instead.

On Fri, Oct 28, 2011 at 1:54 PM, Daniel Fischer <
daniel.is.fischer at googlemail.com> wrote:

> On Friday 28 October 2011, 11:41:15, Eugene Kirpichov wrote:
> > newtype Day = ModifiedJulianDay {toModifiedJulianDay :: Integer}
> > newtype DiffTime = MkDiffTime Pico
> >
> > And Pico is also essentially a newtype for Integer.
> >
> > So, I'm getting warnings on this definition of UTCTime.
> > QUESTION: Is it the case that I can only UNPACK primitive fields, and
> > not even their newtypes?
>
> The problem is that you can't {-# UNPACK #-} Integer.
> You can only unpack single-constructor types.
>



-- 
Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
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