Not a typechecker bug; more a bizarre consequence of
overlapping instance decls.
The instance decl
instance Holidays a = Eq a
overlaps with absolutely every other instance decl for Eq.
In order to make Lattice (Inv a) an instance of Eq, we have
to satisfy Eq (Inv a), since Eq is a
Discern that the following program is apparently well-typed:
module M2 where
class Eq a = Lattice a where
bottom :: a
data Inv a = INV a
deriving Eq
instance Lattice a = Lattice (Inv a)
class Holidays a where
holCode :: a - Int
-- instance Holidays a = Eq a
Now,
After applying the *patch* to .../GC.c of ghc-4.02
i start "making" ghc-4.02 from sources with ghc-4.01
- everything - for and under linux, i386.
So,
myfptools ... ./configure; edit mk/build.mk; make all
yields
[...]
gcc -Iparser -I. -I../includes -O-c parser/ctypes.c -o
SPECIALIZE with '=' is very desirable.
Otherwise, how can one denote with the same name a function together
with its particularly efficient specialization?
Yes it's desirable. I'm not sure how soon we'll get to it
unless other people start yelling too!
In general, expect a quiet patch
Quite impressed with 4.02 so far -- it walks the walks, see promohype
elsewhere, why should I give you all too much free advertising? ;-)
It does indeed seem to be more go-faster than 3.02, _but_:
No profiling! Boo, hiss.
Funny space behaviour -- a module I have that contains just
one
I'm not sure that anybody has "accepted"
undecidable type checking.
People using Gofer or C++ seem to have.
-- Lennart
2.in the face of the above, we need to give the compiler more guidance.
Personally, I favour type declarations everywhere: all identifiers should be
introduced as being of a particular specified type.
Of course, whether these principles are compatible with Haskell it another
On Wed, 17 Feb 1999, michael abbott wrote:
As a C++ user (with a background in categories) patiently waiting for
something a lot better, I personally favour two principles:
1.let's go for undecidable type checking. I want the compiler to be able
to do as much work as possible: ideally,
On 16-Feb-1999, Michael Hobbs [EMAIL PROTECTED] wrote:
I'm not sure if this can be cleanly done or not. (I've been able to do
it less-than-cleanly.) What I want to do is define a class where the
instance has an option of what type of parameters some of its functions
can accept. For example,
As a C++ user (with a background in categories) patiently waiting for
something a lot better, I personally favour two principles:
1. let's go for undecidable type checking. I want the compiler to be able
to do as much work as possible: ideally, everything that can be resolved at
compile
On 16 Feb 1999, Carl R. Witty wrote:
Lars Lundgren [EMAIL PROTECTED] writes:
We have already accepted undecidable type checking, so why not take a
big step forward, and gain expressive power of a new magnitude, by
extending the type system to allow dependent types.
Wait a
On 16-Feb-1999, Carl R. Witty [EMAIL PROTECTED] wrote:
I'm not sure that anybody has "accepted" undecidable type checking.
I think it's becoming clear by now that the theoretical disadvantages
of undecidable type checking are often not significant in practice.
Experience with C++, Gofer, ghc,
What's wrong with
class Foo a b where
write :: a - b - IO ()
?
Well, it's not Haskell. :-)
-- Lennart
Alexander Jacobson [EMAIL PROTECTED] writes:
* facilitate better integration with other languages/systems
For example, it would be nice to be able either to generate a Haskell
datatype from an XML DTD or to generate a XML DTD from a Haskell
datatype.
Funnily enough, that's exactly what
Fergus Henderson wrote:
On 17-Feb-1999, Lennart Augustsson [EMAIL PROTECTED] wrote:
What's wrong with
class Foo a b where
write :: a - b - IO ()
?
Well, it's not Haskell. :-)
Oh, good point blush. I forgot about that.
Please take my mail above as
Alexander Jacobson [EMAIL PROTECTED] writes:
* facilitate better integration with other languages/systems
For example, it would be nice to be able either to generate a Haskell
datatype from an XML DTD or to generate a XML DTD from a Haskell
datatype.
Funnily enough, that's exactly
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