Re: ghc on Win32
Matthias, I've just installed ghc-4.08 / binary release for Win32. When compiling a file Type.hs, the following happens: START Compiling Type.hs does not exist Action: openFile Reason: file does not exist /tmp/ghc1096.cpp END I had the same problem, until I read the following from http://www.haskell.org/ghc/docs/latest/set/book-users-guide.html : ## Furthermore, it seems that TMPDIR must be set to a directory in the same file system in which you invoke GHC. Otherwise you get very werid messages when you invoke GHC, such as: does not exist Action: openFile Reason: file does not exist /tmp/ghc11068.cpp We think this is due to a bug in Cygwin. ## So if your source file is in d:/src, and your TMPDIR is c:/tmp, you probably need to: cd c: path/to/ghc/bin/ghc //d/src/Type.hs -- Zhanyong Wan Dept of Computer Science, Yale University
form of class constraints
I'm using the GHC 4.08 binary distribution on Windows. According to the Haskell 98 report, class constraints are of the form C (a t1 ... tn), where C is a class, a is a type variable, and t1, ..., tn are arbitrary types (including type variables, n = 0). However, the following code failed to compile: ## module Test where newtype StateT s t b x = StateT (s - t b (s, x)) instance Functor (t b) = Functor (StateT s t b) ## Illegal constraint `Functor (t b)' in instance context (Instance contexts must constrain only type variables) I have no problem with the same code in Hugs. Is this a GHC bug? -- Zhanyong Wan Dept of Computer Science, Yale University
Time profiling interval?
While trying to generate a heap profile for a large run, I was getting lots of floating point exceptions when running hp2ps. Normally, I'd have used "+RTS -i5" (or the like) to reduce the number of samples being generated (which, I think, avoids the heap overflow and would also reduce runtime to an acceptable amount). So, the question is: how do I set the profiling interval? (btw the online users guide still documents the -i flag) -- Alastair Reid[EMAIL PROTECTED]http://www.cs.utah.edu/~reid/
RE:
-Original Message- From: Matthias Kilian [mailto:[EMAIL PROTECTED]] Sent: 06 August 2000 22:01 To: Mirko Pracht Cc: [EMAIL PROTECTED] Subject: Re: On Sun, 6 Aug 2000, Mirko Pracht wrote: average x | null x= 0.0 What does you make thinking the average of an empty list is 0? Its' obviously _|_, thus average xs = sum xs / length xs does this not need a "fromInt" to keep it happy I seem to remember a function genericLength once upon a type ... has this been removed nowadays? [which is inefficient, but simple] Kili -- _|_ is pronounced 'bottom', and is the greatest lower bound of a complete lattice. Nick Williams in comp.lang.functional
Re: Haskell and the NGWS Runtime
"Chris Saunders" [EMAIL PROTECTED] writes: It seems to me that this .Net thingy is a runtime and therefore could potentially be as portable as anything from Java. Potentially, yes. This runtime just needs to be ported to other operating systems similarily to the Java runtime. So it's a question of either source availability - or at least a very complete specification - or Microsoft strategy. -kzm -- If I haven't seen further, it is by standing in the footprints of giants
RE: Haskell and the NGWS Runtime
It is not what language that you want on your phone that matters -- you
didn't write the software. What matters is any development team can pick
the language they prefer to use and make their software portable to your
phone or your PC.
-Original Message-
From: Nigel Perry [mailto:[EMAIL PROTECTED]]
Sent: Friday, August 04, 2000 12:54 AM
To: [EMAIL PROTECTED]
Subject: Re: Haskell and the NGWS Runtime
We're drifting a bit off Haskell here, but...
At 10:57 am +1000 4/8/00, Kevin Glynn wrote:
I don't believe this says anything about support for other OS's. I
think the devices here are hardware, (PCs, handhelds, phones, fridge
interfaces, ...) Of course Microsoft believes that some day, very
soon, all devices will run (a version of) Windows. Hence this
statement refers to Microsoft's announced plans to port .NET to all
Windows OS's, including WinCE.
Do you have another reference which is more convincing?
I haven't seen a WinCE version but at a recent conference one of the
exhibitors was offering a .NET on WindowsCE course - however when I
inquired they just said "ask MS, we don't know, we just teach the
courses" (somehow I don't think I'll be recommending them!) So that's
not too convincing!
They are talking phones - but that has to be a stripped down version.
However I'm not sure why I want Haskell on my phone ("the phone with
higher-order polymorphic lazy dialing"?)
As to others OSES...
At 10:24 pm -0400 3/8/00, Chris Saunders wrote:
It seems to me that this .Net thingy is a runtime
and therefore could potentially be as portable
as anything from Java. This runtime just needs
to be ported to other operating systems similarily
to the Java runtime.
Porting JVM is a big enough job (you find a lot of "native"
methods...) .NET has more paraphernalia than the JVM so it will be
quite a job. However I think MS is moving to "standardise" the IL
(the byte codes) which I guess is to suggest it is not a moving
target (not the the JVM really is but I hear the lack of JVM 2's has
been blamed on lack of info out of Sun - but that might be just
passing the blame)
At 5:59 pm +0200 3/8/00, Juan J. Quintela wrote:
nigel Disclaimer, as Fergus added one: I am working with Microsoft on .NET
nigel implementation, but I run Windows 2000 on my G3 PowerBook and take
it
nigel to Microsoft with me. I'm biased on everything :-)
Windows 2000 in a G3 Powerbook? I am lost here :((
Why have any other computer when you can have a Mac?
Mine runs:
DVD Movies
MacOS
JVM
Playstation games
Windows 95
Windows 2000 (a bit slugglish)
and could run:
Linux (but I have no use for it at present)
At 2:07 am +1000 4/8/00, Fergus Henderson wrote:
Note that on x86 there are only six general purpose registers,
so you very quickly run out...
Who uses the x86? Oh I remember... ;-)
Cheers,
Nigel
--
--
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 insult cyclists' like their predecessors?
Politics and hypocrisy before safety - the NZ Helmet Law, NZ's Shame
RE: Haskell and the NGWS Runtime
Back to the language wars then. It does seem like integration of Haskell and the NGWS is a graunch, largely because Haskell is not OO. Is there anything preventing Haskell from becoming OO and seamlessly fitting into the NGWS? Or from designing a functional language that would be a good fit into the NGWS. A major problem I see is that there is probably a standard set of container classes in NGWS which have a high impedance mismatch with the lists functional languags use for their constructions. Can we ever have functional programming "in the large" given the OO paradigm and NGWS are both here to stay? This can not happen until I can get a language which seamlessly fits into NGWS (or some similar thing on a non-windows platform). -Original Message- From: Antony Courtney [mailto:[EMAIL PROTECTED]] Sent: Sunday, August 06, 2000 3:49 PM To: Jürgen A. Erhard Cc: [EMAIL PROTECTED] Subject: Re: Haskell and the NGWS Runtime "Jürgen A. Erhard" wrote: "Manuel" == Manuel M T Chakravarty [EMAIL PROTECTED] writes: Manuel "Erik Meijer" [EMAIL PROTECTED] wrote, [...] The lab is *sponsored* by Microsoft, but definitively not *at* Microsoft. I doubt there are any Linux boxes at Microsoft :-) Manuel [...] There have also been reports of Linux boxes in the main Manuel company, but the validity of these reports is of course not But easy to believe... I mean, wouldn't you take a good look at your competition? Having spent five years doing Windows and Win32 hacking, and 10+ years doing Unix hacking before that, I can assure you there is little evidence that Microsoft are interested in learning anything whatsoever from Linux or any other Unix work-alike. Rather than re-iterate the argument, I'll simply point interested readers towards the excellent article "Working with Win32: the good, the bad and the ugly" by David G. Korn http://www.usenix.org/publications/login/1997-11/win32.html which mostly reinforces the quote: Those who do not understand Unix are condemned to reinvent it, poorly. -- Henry Spencer Now that I've gotten MY little barb in, can we PLEASE end this tangent on OS wars, and return to our regularly scheduled language wars? :-) Thanks, -Antony (haskell list lurker) -- Antony Courtney [EMAIL PROTECTED] http://www.apocalypse.org/pub/u/antony
unlines: the mystery of the trailing \n
Here's a Prelude inconsistency that's been irking me once in a while for a loong time - today it came up again, so here goes: unlines ["a","b"] == "a\nb\n" unwords ["a","b"] == "a b" I like that unwords (ls1 ++ [unwords ls2]) == unwords (ls1 ++ ls2) but not that 'unlines' doesnt' obey the same rule, i.e., unlines [line1, unlines [line2,line3]] /= unlines [line1,line2,line3] Is this by design? I notice that 'unlines' mirrors Miranda's 'lay', but I'd find it a little more useful without the trailing \n (esp. considering now that putStrLn is std.) The current defn of 'unlines' doesn't keep me up at night, but still. --sigbjorn
Re: unlines: the mystery of the trailing \n
Here is a concern: At present, a final \n in lines' input is optional, because a line is ended by either a \n or the end of the string. Consequently lines "a" and lines "a\n" have the same value ( ["a"] ). This seems a desirable feature that is worth preserving. Consider the composition lines.unlines, and what happens when the last line is empty. unlines ["a", ""] is "a\n\n", and lines correctly reconstructs the two lines from this. With this suggestion, unlines ["a", ""] becomes "a\n", which, unless you change its behaviour, lines interprets as representing a single line ["a"], and lines.unlines is no longer the identity function. --brian Sigbjorn Finne wrote: Here's a Prelude inconsistency that's been irking me once in a while for a loong time - today it came up again, so here goes: unlines ["a","b"] == "a\nb\n" unwords ["a","b"] == "a b" I like that unwords (ls1 ++ [unwords ls2]) == unwords (ls1 ++ ls2) but not that 'unlines' doesnt' obey the same rule, i.e., unlines [line1, unlines [line2,line3]] /= unlines [line1,line2,line3] Is this by design? I notice that 'unlines' mirrors Miranda's 'lay', but I'd find it a little more useful without the trailing \n (esp. considering now that putStrLn is std.) The current defn of 'unlines' doesn't keep me up at night, but still. --sigbjorn
RE: unlines: the mystery of the trailing \n
Hi Sigbjorn, | Here's a Prelude inconsistency that's been irking me once | in a while for a loong time - today it came up again, so here goes: | | unlines ["a","b"] == "a\nb\n" | unwords ["a","b"] == "a b" | | [... unwords adds space between items, not at the beginning or end; | unlines puts a newline after each item, including at the end ...] I quite like the fact that the definition for unlines gives us laws like: unlines (xs ++ ys) = unlines xs ++ unlines ys unlines . concat = concat . map unlines Of course, the fact that unwords doesn't add a terminating space means that we don't get quite such nice laws for unwords ... All the best, Mark
