Re: (no subject)
[EMAIL PROTECTED] writes: I am a student who study a computer programing. I want to have Haskell software to study . However, it is very hard to get the Haskell . and I hope you give me the way to get the Heskell. If you mail me to show the way to get the Heskell , I would appreciate your kindness. See http://haskell.org/hugs/ for an easily installed Haskell compiler. It has version for Windows and Unix. See http://haskell.org/implementations.html for other versions. See http://haskell.org/ for lots of other information. -- Alastair Reid[EMAIL PROTECTED]http://www.cs.utah.edu/~reid/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: (no subject)
I'm not sure where the documentation is, but here's the idea on how to
used named fields. I'll make a smaller example, though :)
data T = T { x :: Int, y :: Bool }
now, to create a value of type T, you can write:
x = T 5 True
as the datatype declaration creates the following function:
T :: Int - Bool - T
You can also pattern match as if you had just declared it as data T = T
Int Bool. However, this datatype declaration introduces two functions
into the namespace:
x :: T - Int
y :: T - Bool
which extract values. for instance:
x (T 5 True)
evaluates to 5 and
y (T 5 True)
evaluates to True.
You can also use field names to create values:
T { x = 5, y = True }
or
T { y = True, x = 5}
order is irrelevant (i'm not sure about rules if you specify the same
field more than once...check in the report on that).
Finally, you can update parts of labelled fields independent of everything
else:
let q = T {x=4, y=True}
q' = q {x=5}
in q'
will yield T 5 True.
Of course, this isn't value replacement, it's just a more convenient way
to create a new value based on an old one, with minor changes.
I see Ashley also replied to this thread with a pointer to
documentation. Hopefully the combination will help.
--
Hal Daume III
Computer science is no more about computers| [EMAIL PROTECTED]
than astronomy is about telescopes. -Dijkstra | www.isi.edu/~hdaume
On 25 Feb 2002, Tom Bevan wrote:
Hi,
I've come across this sort of data constructor below many times but I'm
not really sure how to use it. Can someone please point me to the right
section in the documentation?
In particular, I want to know how to create a calendar time and how to
access the fields .
Tom
data CalendarTime = CalendarTime {
ctYear :: Int,
ctMonth :: Month,
ctDay, ctHour, ctMin, ctSec :: Int,
ctPicosec :: Integer,
ctWDay:: Day,
ctYDay :: Int,
ctTZName :: String,
ctTZ :: Int,
ctIsDST :: Bool
} deriving (Eq, Ord, Read, Show)
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Re: (no subject)
uma kompella wrote:
hi
i am new to haskell and am having a problem to write
function which takes a boolean expression and returns
a truthvalue stating whether or not it is a tautology.
Can anyone please help me??
Thanks a lot
uma
I assume this is your homework. It is better to say so explicitly.
Think about this: what does it mean for an expression to be a
tautology? Can you think of an a way to check this? Once you've come
up with a way to check this, it should be quite easy to write it in
Haskell.
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Re: (no subject)
At 2001-12-10 16:07, uma kompella wrote: i am new to haskell and am having a problem to write function which takes a boolean expression and returns a truthvalue stating whether or not it is a tautology. If you really want to impress your tutor, see if you can find a function that does this in polynomial time. -- Ashley Yakeley, Seattle WA ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Haskell -- Java was Re: (no subject)
Have a look at http://www.mondrian-script.org Erik - Original Message - From: "Chris Angus" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, November 24, 2000 1:44 AM Subject: (no subject) I was wondering if Has anybody had access to a Haskell - Java compiler/translator. - Chris Angus Armature Enterprise House 1 Apex View Leeds LS11 9BH +44 113 2595253 [EMAIL PROTECTED] ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Haskell -- Java was Re: (no subject)
Sorry folks the Haskell compiler at http://www.mondrian-script.org doesn't produce Java, yet... Actually the compiler *does* produce Java but it has been turned off as there is no Haskell Prelude for Java yet, that bit is currently only for .NET. We'll produce such a Java Prelude when we get the time, no promises as to when at present - .NET is our first priority at the moment. (For the technically minded the GHC Prelude is a mix of Haskell and C, its getting the C stuff converted for JVM/.NET which takes the time.) However there is a Mondrian compiler on the site which does produce Java, so maybe that will do you in the meantime. At 8:48 am -0800 24/11/00, Erik Meijer wrote: Have a look at http://www.mondrian-script.org Erik - Original Message - From: "Chris Angus" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, November 24, 2000 1:44 AM Subject: (no subject) I was wondering if Has anybody had access to a Haskell - Java compiler/translator. -- -- Dr Nigel PerryEmail: [EMAIL PROTECTED] IIST Tel: +64 6 350 5799 2477 Massey University Fax: +64 6 350 2259 Palmerston North FTP/WWW: smis-asterix.massey.ac.nz New Zealand It makes as much sense to wear a "cycle" style helmet in a car as on a bike... Choosing to wear one on a bike but not in a car is mere inconsistency. Refusing to wear one in a car while insisting others do so on a bike is pure hypocrisy. Will the new Labour government repeal the National government's hypocrisy, or will they discriminate against cyclists like their predecessors? Politics and hypocrisy before safety - the NZ Helmet Law, NZ's Shame ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
