* In GHC 8.4.1, the operator <> has become a method of the Semigroup class
and is exported from the Prelude. This is unfortunate, since <> is also
exported from the standard library module Text.PrettyPrint, so in any
module that defines a pretty printer, there is likely to be an ambiguity.
This affects ~18 modules in GF. Solution:
import Prelude hiding (<>)
This works also in older versions of GHC, since GHC does't complain if
you hide something that doesn't exists.
* In GHC 8.4.1, Semigroup has become a superclass of Monoid. This means
that anywhere you define an instance of the Monoid class you also have to
define an instance in the Semigroup class.
This affects Data.Binary.Builder in GF. Solution: conditionally define
a Semigroup instance if compiling with base>=4.11 (ghc>=8.4.1)
The standard binary package has improved efficiency and error handling [1], so
in the long run we should consider switching to it. At the moment, using it is
possible but not recommended, since it results in incomatible PGF files.
The modified modules from the binary package have been moved from
src/runtime/haskell to src/binary.
[1] http://lennartkolmodin.blogspot.se/2013/03/binary-07.html
Fixes the following build failure:
src/runtime/haskell/Data/Binary/IEEE754.lhs:256:17:
Could not deduce (Num a) arising from a use of `mask'
from the context (Bits a)
bound by the type signature for
clamp :: Bits a => BitCount -> a -> a
GF produced slightly different PGF files on 64-bit systems and 32-bit systems.
This could cause problems when a PGF was produced on a 32-bit system and used
on a 64-bit system.
To fix this, the GF compiler and the Haskell PGF run-time library now reads
and writes PGF files like the 32-bit version even when compiled on a 64-bit
system.
Note: the Haskell type Int is still used internally in GF, which could be
32 bits or 64 bits...
The default binary representation in haskell's Data.Binary package is
homemade and quite complicated. Making it compliant with IEEE 754 will
make it easyer for the java runtimes (and probably others) to load the
PGF.
