Gentle Haskellers
Would you be interested in working for three months at Microsoft
Research, Cambridge, on a project related to GHC or Haskell?
MSR Cambridge now takes interns *year-round*, not just in the summer
months. Simon Marlow and I are keen to attract motivated and
well-qualified folk
I am trying to derive MyOrd class from Eq (Prelude):
class Eq a = MyOrd a where
(%=), (%), (%=) :: a - a - Bool
x %= y = (x y || x == y)
x % y = y x
x %= y = (y x || x == y)
I get these errors:
ClassTest.hs:28:21:
Could not deduce (Ord a) from the context
I am trying to derive MyOrd class from Eq (Prelude):
class Eq a = MyOrd a where
(%=), (%), (%=) :: a - a - Bool
x %= y = (x y || x == y)
x % y = y x
x %= y = (y x || x == y)
Q: What's wrong? Why 'Ord' gets into play here?
You are using which is a function
Sorry, left out an important verb, *hide*:
You can the prelude and thus the Ord class and make your own and
You can *hide* the prelude and thus the Ord class and make your own and
Jared.
--
http://www.updike.org/~jared/
reverse )-:
___
Hello Dmitri,
Tuesday, July 25, 2006, 8:15:41 PM, you wrote:
class Eq a = MyOrd a where
(%=), (%), (%=) :: a - a - Bool
x %= y = (x y || x == y)
x % y = y x
x %= y = (y x || x == y)
you are mixing definition of class and its (default) instance. try the
What time on September 14th will the GHC Hackathon begin? I don't need a precise answer, just a quick one. Plus or minus an hour will do.Thanks,Greg
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Bulat,
Dmitri is not necessarily mixing [...] class and its (default)
instance.
Bulat, one could suspect a reasonable use of default class methods:
http://www.haskell.org/onlinereport/decls.html#overloading
Indeed, Dmitri's declarations make sense as default class methods.
... except for Jared's
What time on September 14th will the GHC Hackathon begin? I don't need a
precise answer, just a quick one. Plus or minus an hour will do.
Morning certainly. In the absence of a more definite answer from the
Simons (or the Galois hosts), I would guess 0900-1000hrs local time.
Regards,
Hello Ralf,
Tuesday, July 25, 2006, 9:59:58 PM, you wrote:
Dmitri is not necessarily mixing [...] class and its (default)
instance.
sorry, i was thoughtless. it really seems like a mistake in use MyOrd
class instead of attempt to use Ord operations. Dmitri should know
better :)
--
Best
Hi,
I was playing around with runhaskell (runghc to be precise), and I discovered
the limitation wherein you have to use the file suffix .hs. Don't get me
wrong, runhaskell is great, but if you didn't have that restriction it would
make haskell much more attractive to many programmers who
Well now that I understand how it works, I'm perfectly happy with the
current functionality.
As long as I put all my FFI imports into one module and compile that,
then I can load the other modules into GHCi at will
during development and testing. I was going to do some FFI imports into
another
vim has been my choice as well. Now that vim 7.0 has tabbed windows
it's better than ever.
All they need now is a way to integrate it with a console window
I guess you can find scite/scintilla settings for Haskell as well
http://www4.in.tum.de/~haftmann/resources/haskell.properties
Marc
Looking through the mailing list I see something from May 2005 on this
topic about adding the equivalent of gcc's -x option to ghc. What's the
status of that?
You should always be able to do something like this:
#!/usr/bin/runfileAsHSFile $@
module Main where
import
blah
[Sorry for the late reply.]
On Wed, Jul 19, 2006 at 03:16:48AM +0100, Neil Mitchell wrote:
I want to make sure a filename is valid. For example, prn and con
This is another rat's nest, so I suggest that it be dealt with
separately from the basic filepath module. The notion of valid is
I have a query which is asked out of interest's sake...
I'm essentially looking for an affirmation of what I think I already
understand (or some info if I'm deluded ;)).
To put this in context...
I have some C code...
typedef int func(void *);
void from_maybe_int(void *val, func
Hi
It's already there - see System.Directory.createDirectoryIfMIssing.
I'd missed that one entirely, and I think other people had (because I
added ensureDirectory at a request of several people), will go.
If we have shortPath at all, perhaps it would be better named
Hi
Its a rats nest to do it properly, but some very basic idea of does
this path have things which there is no way could possibly be in a
file - for example c:\|file is a useful thing to have.
This seems to encourage the classic mistake of checking not known bad
rather than known good.
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