[Haskell-cafe] Re: Syntax question regarding 'import'
Maurcio [EMAIL PROTECTED] wrote:
About this teste code:
module Main (main) where {
import Foreign hiding (unsafePerformIO,Foreign.Ptr,Data.Bits,) ;
blo = xor 10 10 :: Int ;
main = return ()
}
You're only hiding the typeclass Data.Bits, not the function xor. To do
that, you have to write
import Foreign hiding (unsafePerformIO,Data.Bits(..))
Generally, I'd use
import Foo(bar, Baz, Quux(..)) as F
(or even using qualified) instead of using hiding, it may be more
verbose but is way less confusing. Actually, I usually just write
import qualified Foo as F
and don't ever have to worry about name clashes.
--
(c) this sig last receiving data processing entity. Inspect headers
for copyright history. All rights reserved. Copying, hiring, renting,
performance and/or quoting of this signature prohibited.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Syntax question regarding 'import'
About this teste code:
module Main (main) where {
import Foreign hiding (unsafePerformIO,Foreign.Ptr,Data.Bits,) ;
blo = xor 10 10 :: Int ;
main = return ()
}
You're only hiding the typeclass Data.Bits, not
the function xor. To do that, you have to write
import Foreign hiding (unsafePerformIO,Data.Bits(..))
Generally, I'd use (...)
import qualified Foo as F
and don't ever have to worry about name clashes.
Agree. I'm asking this because I'm wrting my
syntax reference. Is that a GHC extension? Look at
this (from haskell 98 report sections 5.2 and
5.3):
export - qvar
| qtycon [(..) | ( cname1 , ... , cnamen )]
| qtycls [(..) | ( var1 , ... , varn )]
| module modid
import - var
| tycon [ (..) | ( cname1 , ... , cnamen )]
| tycls [(..) | ( var1 , ... , varn )]
It seems 'modid's are included when exporting
names, but not when importing.
Maurício
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
