Using unboxed integers
I have x, y :: Int# I expect that x <=# y :: Bool but ghc 7.8 says Couldn't match expected type âBoolâ with actual type âInt#â In the expression: x <=# y In an equation for âbâ: b = x <=# y I have MagicHash and I've imported the right modules so that <=# is recognised as *something*, but at this point I'm baffled. I'm also not clear on how I can show an Int#.
Use the isTrue# function which is made visible by importing GHC.Base.
isTrue# (x <=# y) :: Bool
You can show an Int# by wrapping it up in an I# data constructor and
applying show to it:
x# :: Int#
show (I# x#) ::String
You can make the I# data constructor visible via GHC.Base like above.
Hope that helps!
Rahul
On Wed, Nov 2, 2016 at 11:20 AM, Richard A. O'Keefe
I have x, y :: Int# I expect that x <=# y :: Bool but ghc 7.8 says Couldn't match expected type ‘Bool’ with actual type ‘Int#’ In the expression: x <=# y In an equation for ‘b’: b = x <=# y
I have MagicHash and I've imported the right modules so that <=# is recognised as *something*, but at this point I'm baffled.
I'm also not clear on how I can show an Int#.
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-- Rahul Muttineni
import GHC.Base isTrue# (comparison) show (I# x#) worked. Thank you very much. This made a barely measurable difference to my program, so I now that I know how to use unboxed integers, I can forget again.
If you look at the Core GHC produces (with -ddump-simpl), you'll probably
see that the Ints have been unboxed for as many operations as possible, so
manual unboxing won't make that much difference.
On Nov 2, 2016 1:15 AM, "Richard A. O'Keefe"
import GHC.Base isTrue# (comparison) show (I# x#) worked. Thank you very much.
This made a barely measurable difference to my program, so I now that I know how to use unboxed integers, I can forget again. _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.
participants (3)
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Rahul Muttineni -
Richard A. O'Keefe -
Zemyla