[Haskell-cafe] Hoogle problems?
I've just tried using Hoogle, but either get a 404 not found (http://haskell.org/hoogle/) or else I find I get a ELF 64-bit LSB executable being downloaded If I search using Google and click on the first link (shown as www.haskell.org/hoogle/ I get the following (spaces deliberately added to make it less dangerous) https://www.goo gle.com/url?sa=trct=jq=esrc=ssou rce=webcd=1cad=rjaved=0CC8QFjAAurl=http%3A%2F%2Fwww.haskell.org%2Fhoogle%2Fei=y_njUdZAhY 7sBsGpgNAKusg=AFQjCNFljq5Oyb4LT7VF-I5MUotq512AQgsig2 =SVRE_6nF3bhho7-NKqEaCwbvm=bv.487 05608,d.ZGU Using Mac OS X 10.6, Chrome and Safari Is it me, or is there a wider problem ? Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] mapFst and mapSnd
I have them defined for my stuff. Generally I find it much quicker to roll my own than to (1) ask on this list if someone else has done it... (2) look at arrows or MyFavouriteCategoryTheoryBitOfFPBecauseICantGetAbstractEnough and the try to figure out what is going on. The joy of Haskell is both that rolling your own is often so easy, and that there are lots of approaches out there that allow you to get abstract as well... Regards, Andrew (Engineering graduate, feet still firmly embedded in concrete :-) On 28 May 2013, at 09:54, Dominique Devriese wrote: Hi all, I often find myself needing the following definitions: mapPair :: (a - b) - (c - d) - (a,c) - (b,d) mapPair f g (x,y) = (f x, g y) mapFst :: (a - b) - (a,c) - (b,c) mapFst f = mapPair f id mapSnd :: (b - c) - (a,b) - (a,c) mapSnd = mapPair id But they seem missing from the prelude and Hoogle or Hayoo only turn up versions of them in packages like scion or fgl. Has anyone else felt the need for these functions? Am I missing some generalisation of them perhaps? Regards, Dominique ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Teaching FP with Haskell
Rustom, you should look at Helium - http://www.cs.uu.nl/wiki/bin/view/Helium/WebHome Andrew. On 21 May 2013, at 10:55, Rustom Mody wrote: We are offering a MOOC on haskell : https://moocfellowship.org/submissions/the-dance-of-functional-programming-languaging-with-haskell-and-python Full Announcement on beginners list : http://www.haskell.org/pipermail/beginners/2013-May/012013.html One question that I have been grappling with in this regard: How to run ghc in lightweight/beginner mode? 2 examples of what I mean: 1. gofer used to come with an alternative standard prelude -- 'simple.pre' Using this, gofer would show many of the type-class based errors as simple (non-type-class based) errors. This was very useful for us teachers to help noobs start off without intimidating them. 2. Racket comes with a couple of levels. The easier numbers were not completely consistent with scheme semantics, but was gentle to beginners Any thoughts/inputs on this will be welcomed Rusi ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Markdown extension for Haddock as a GSoC project
My 2c (before such coins disappear...) On 2 May 2013, at 09:14, Petr Pudlák wrote: Hi, Personally I'd incline to choose some existing, well-established markup language with formal specification that supports math (hopefully there is one). So TeX/LaTeX is out then :-( Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GSoC Project Proposal: Markdown support for Haddock
On 4 Apr 2013, at 22:53, Aleksey Khudyakov wrote:
If we are going to change haddock syntax we should add ability to add
math formulae to documentation. It's not currently possible and it makes
documenting numeric code properly difficult.
How about support for .lhs files?
- both those with bird-tracks (which I don't use anymore)
and \begin{code}...\end{code} (which I do use).
My .lhs files are also LaTeX sources - I guess some way to nicely integrate
haddock markup/down/whatever with LaTeX stuff would be needed
+1 in any case
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Re: [Haskell-cafe] GSoC Project Proposal: Markdown support for Haddock
I'm not proposing the LaTeX is used for hyperlinking the
reference - hence my comment about nicely integrating
Perhaps a \begin{haddock} ... \end{haddock} environment* ?
* This would only affect those using LaTeX/lhs - everyone else could haddock**
as usual
** haddock = whatever markdow/up/sideways scheme you guys come up with...
On 5 Apr 2013, at 16:22, Aleksey Khudyakov wrote:
On 5 April 2013 12:20, Andrew Butterfield
andrew.butterfi...@scss.tcd.ie wrote:
On 4 Apr 2013, at 22:53, Aleksey Khudyakov wrote:
If we are going to change haddock syntax we should add ability to add
math formulae to documentation. It's not currently possible and it makes
documenting numeric code properly difficult.
How about support for .lhs files?
- both those with bird-tracks (which I don't use anymore)
and \begin{code}...\end{code} (which I do use).
My .lhs files are also LaTeX sources - I guess some way to nicely integrate
haddock markup/down/whatever with LaTeX stuff would be needed
I'm not sure that it would help. If we to use haddock markup it need to
support math typesetting. And LaTeX IMHO isn't right tool for creating
hyperlinked API reference
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Re: [Haskell-cafe] What Haskell Records Need
On 2 Aug 2012, at 09:25, Erik Hesselink wrote:
Isn't this exactly the problem solved by all the lens packages?
Current popular ones are fclabels [0] and data-lens [1].
[0] http://hackage.haskell.org/package/fclabels
[1] http://hackage.haskell.org/package/data-lens
Not sure what all of these do, but I have a simple solution I use
in my work:
Take the following types from a contrived
example.
type Salary = Integer
data Job = Job
{ title :: String
, salary :: Salary
}
Rather than setTitle :: String - Job - Job we lift the first argument
and define
setfTitle :: (String - String) - Job - Job
setfTitle f jobrec = jobrec{ title = f $ title jobrec }
then setTitle = setfTitle . const
This is all just boilerplate, so we continue
setfSalary :: (Salary - Salary) - Job - Job
setfSalary f jobrec = jobrec{ salary = f $ salary jobrec }
data Person = Person
{ name :: String
, job :: Job
}
setfName :: (String - String) - Person - Person
setfName f prec = prec{ name = f $ name prec }
setfJob :: (Job - Job) - Person - Person
setfJob f prec = prec{ job = f $ job prec }
Now we can use function composition to do two levels
setfTitleInPerson :: (String - String) - Person - Person
setfTitleInPerson = setfJob . setfTitle
setTitleInPerson :: String - Person - Person
setTitleInPerson = setfTitleInPerson . const
Simple function composition works to put these together...
I was frustrated by this problem a while back, and decided to approach it
formally
(I write literate Haskell/LateX documents), and went to work, doing the math
with the intention of writing a suitable combinator, until I discovered I didn't
need one lifting from X - R - R to (X - X) - R - R gave me all I
needed...
Since I've used record syntax, I get
getter/accessor functions (title, salary,
name, job) for free. Now suppose I want to
create an aggregate getter function: return
the salary of a given person. Piece of cake,
it's just function composition
getSalary :: Person - Salary
getSalary = salary . job
Done! Now suppose I want to write a
setter/mutator function for the same nested
field
setSalaryMessy :: Salary - Person - Person
setSalaryMessy newSalary person =
person {
job = (job person) {
salary = newSalary
}
}
Ouch! And that's not even very deeply nested.
Imagine 4 or 5 levels deep. It really makes
Haskell feel clunky next to `a.b.c.d = val`
that you see in other languages. Of course
immutability means that the semantics of
Haskell are quite different (we're creating
new values here, not updating old ones) but
it's still common to model change using these
kinds of updates.
What if along with the free getters that
the compiler generates when we use record
syntax, we also got semantic editor
combinator (SEC) functions[0] that could be
used as follows?
setSalary newSalary = job' $ salary' (const newSalary)
giveRaise amount = job' $ salary' (+amount)
givePercentRaise percent = job' $ salary' (*(1+percent))
For each field x, the compiler generates a
function x' (the tic is mnemonic for change).
These little functions aren't hard to write,
but they're classic boilerplate.
job' :: (Job - Job) - Person - Person
job' f person = person {job = f $ job person}
salary' :: (Salary - Salary) - Job - Job
salary' f job = job { salary = f $ salary job}
These type of utility functions are a dream
when working with any reference type or
State Monad.
modify $ givePercentRaise 0.25
The compiler could also generate polymorphic
SEC functions for polymorphic fields.
Further, the compiler could disallow using
old-style update syntax for fields whose SEC
update function is not in scope, giving us
fine-grained control over access and update.
On the other hand we currently have to create
new functions to achieve this (exporting the
getter means exporting the ability to update
as well, currently).
Of course this doesn't address the
namespacing issues with records, but it is
likely nicely orthogonal to other proposals
which do.
Also note that there's a package on hackage [1]
that will generate SEC functions using TH.
It's nice, but I prefer the style of field
names used above for updaters (field' vs
editField).
Let me know what you think. I'll write up an
official proposal if there's a bit of
general interest around this.
Thanks for reading,
--Jonathan
[0] - http://conal.net/blog/posts/semantic-editor-combinators
[1] -
http://hackage.haskell.org/packages/archive/sec/0.0.1/doc/html/Data-SemanticEditors.html
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Re: [Haskell-cafe] What Haskell Records Need
Ah yes - the joy of Haskell It so easy to roll your own, rather than search to find someone else's (better/more elegant) solution... :-) On 2 Aug 2012, at 11:41, Erik Hesselink wrote: On Thu, Aug 2, 2012 at 12:30 PM, Andrew Butterfield andrew.butterfi...@scss.tcd.ie wrote: On 2 Aug 2012, at 09:25, Erik Hesselink wrote: Isn't this exactly the problem solved by all the lens packages? Current popular ones are fclabels [0] and data-lens [1]. [0] http://hackage.haskell.org/package/fclabels [1] http://hackage.haskell.org/package/data-lens Not sure what all of these do, but I have a simple solution I use in my work: They do exactly that. They create 'lenses' which are getters/setters/modifiers combined, and allow you to compose these to get/set/modify deep inside nested data types. Look at the examples in the fclabels documentation [2] for more details. [2] http://hackage.haskell.org/packages/archive/fclabels/1.1.4/doc/html/Data-Label.html Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I Need a Better Functional Language!
On 5 Apr 2012, at 15:14, Grigory Sarnitskiy wrote: Hello! I've just realized that Haskell is no good for working with functions! Obviously, that's not all of the imaginable possibilities. One also can rewrite programs. And write programs that rewrite programs. And write programs that rewrite programs that rewrite the first programs and so on. But there is no such possibility in Haskell, except for introducing a DSL. So now I wonder, what are the languages that are functional in the sense above? With a reasonable syntax and semantics, thus no assembler. I guess Lisp might be of this kind, but I'm not sure. Probably - but the semantics is dreadful... Note, that the reflectivity is important. Intel developed a reflective functional language/system called Forte that is the basic of a lot of their formal hardware verification process... http://www.cs.ox.ac.uk/tom.melham/res/forte.html ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I Need a Better Functional Language!
Addendum: Intel's Forte was the framework, reFLect was the language : http://www.cs.ox.ac.uk/tom.melham/res/reflect.html Quoting that page: reFLect is a functional programming language designed and implemented by a team at Intel Corporation's Strategic CAD Labs under the direction of Jim Grundy. The language is strongly typed and similar to ML, but provides certain reflection features intended for applications in industrial hardware design and verification. Like LISP, reFLect has quotation and antiquotation constructs that may be used to construct and decompose expressions in the language itself. Unlike LISP, these mechanisms are typed. The language also provides a primitive mechanism for pattern-matching, and in particular for defining functions over code by pattern-matching on the structure of reFLect expressions. On 5 Apr 2012, at 15:14, Grigory Sarnitskiy wrote: Hello! I've just realized that Haskell is no good for working with functions! First, what are 'functions' we are interested at? It can't be the usual set-theoretic definition, since it is not constructive. The constructive definition should imply functions that can be constructed, computed. Thus these are computable functions that should be of our concern. But computable functions in essence are just a synonym for programs. One could expect from a language that bears 'functional' as its characteristic to be able to do everything imaginable with functions. However, the only thing Haskell can do with functions is to apply them to arguments and to feed them as arguments, run in parallel (run and concatenate programs). Obviously, that's not all of the imaginable possibilities. One also can rewrite programs. And write programs that rewrite programs. And write programs that rewrite programs that rewrite the first programs and so on. But there is no such possibility in Haskell, except for introducing a DSL. So now I wonder, what are the languages that are functional in the sense above? With a reasonable syntax and semantics, thus no assembler. I guess Lisp might be of this kind, but I'm not sure. In addition, I'm not a fan of parentheses. What else? Pure? Mathematica? Maxima? Note, that the reflectivity is important. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] interest in Irish Haskell User's Group?
Count me in ! (i've also CCed a colleague) On 24 Jan 2012, at 11:27, John Lato wrote: Hello, Some other Haskellers and I have been discussing starting an Irish Haskell User's Group. I think we're close to critical mass, and need just a few more interested people to give it a run. To that end, I'd appreciate hearing from anyone who would be interested in attending or participating. Our initial meeting would likely be in Maynooth as that's where we're based, however we'd like to see involvement across at least the greater Dublin area, and possibly further afield. So, please let me know if you're interested in participating. I'll post further details when we've established an initial meeting. Thanks, John L. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] black Wikipedia (Was: PhD program at Portland State accepting applications)
Just add ?banner=none to the url if you really have to read the page On 18 Jan 2012, at 17:37, Henning Thielemann wrote: On Wed, 18 Jan 2012, Nathan Collins wrote: - Portland is a very popular US city, known for beer, bikes, music, and street food: http://en.wikipedia.org/wiki/Portland_Oregon (wikipedia is blacked out today) Maybe it is only a JavaScript trick. In Firefox (with JavaScript) I see the complete a page before it is overwritten by the protest page. In Konqueror of KDE 3 (with and without JavaScript) I can read the Wiki pages without problems. Edit however is really disabled. Sometimes I am glad to have the old technology available. :-) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Program used for debugging
On 1 Dec 2011, at 14:10, Yves Parès wrote: Hey, What do you mostly use for debugging? Simple calls to Debug.Trace.trace? Hpc? Hood? Debug.Trace, with some short helpers so dbg x= x displays the value of x, provided x is in Show import Debug.Trace dbg msg x = dbgsh show msg x dbgsh sh msg x = trace (msg++sh x) x cdbg p msg x | p x= dbg msg x | otherwise = x -- if you want to tailor the show: class Dshow t where dshow :: t - String ddbg msg x = dbgsh dshow msg x ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] A Mascot
On 16 Nov 2011, at 08:46, Ertugrul Soeylemez wrote: But I think, despite the well-founded denotational semantics of Haskell, bottom does not play that much of a role. There is one? Where? Last time I looked (a while ago, admittedly) there was no denotational (or any formal) semantics for Haskell. - lots of stuff for fragments of Haskell-like languages or parts of Haskell, but not a full proper definitive semantics for *Haskell*, as found in the wild... Looking at http://en.wikibooks.org/wiki/Haskell/Denotational_semantics the first footnote states In fact, there are no written down and complete denotational semantics of Haskell. This would be a tedious task void of additional insight and we happily embrace the folklore and common sense semantics. However, if you have a proof-based tool used for reasoning about Haskell programs in a safety-critical environment, you might just need to do this tedious task, particularly in order to show your proof rules sound. - has anyone in that area done this? is it available ? Is there a definitive Operational Semantics? Axiomatic? PS - I love the mascot - thanks Heath ! Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife = sex) http://ertes.de/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How unique is Unique
On 27 May 2011, at 08:35, Emil Axelsson wrote: Hello! Lacking a proper blog, I've written some notes about Data.Unique here: http://community.haskell.org/~emax/darcs/MoreUnique/ This describes a real problem that makes Data.Unique unsuitable for implementing observable sharing. Looking at the source for Data.Unique shows that its implemented as an Integer, starting at 0, when the IO monad is started - so the values are only unique within a single I/O run, and are definitely not comparable across runs... The document also proposes a solution that uses time stamps to generate symbols that are more unique. Does anyone have any comments on the proposed solution? Are there any alternatives available? I haven't had time to look at that part yet Thanks! / Emil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Status of Haskell + Mac + GUIs graphics
I have developed a GUI app using wxHaskell I develop using GHCi - invaluable I can run the application once form GHCi, and then a re-run crashes, but - usually after a run there is enough time to re-start GHCi while I tihnk about what needs fixing next - usually I can still run tests and queries from GHCi afterwards... This works because I develop in Windows using GHC 6.10.4 wxHaskell 0.11.1.2 - I haven't upgraded because I believe the GHCi behaviour worsens on later versions of GHC (I'm open to correction on this) - a student of mine has been able to build it on linux using the latest versions of everything - I had to revise some of my code simply because later GHC versions introduced new keywords So - to summarise If you are happy to develop using 6.10.4, on Windows then wxHaskell is workable with GHCi It seems to then build ok on Linux Alas - I have yet to be able to build it on Mac OS X (Snow Leopard) The app ? - see http://www.scss.tcd.ie/Andrew.Butterfield/Saoithin/ On 18 May 2011, at 00:24, Conal Elliott wrote: I still haven't found any way to do GUIs or interactive graphics in Haskell on a Mac that isn't plagued one or more of the following serious problems: * Incompatible with ghci, e.g., fails to make a window frame or kills the process the second time one opens a top-level window, * Goes through the X server, and so doesn't look or act like a Mac app, * Doesn't support OpenGL. A year or two ago, I put my Haskell GUI graphics work on hold while waiting hoping for a functioning pathway to open. So far I haven't heard of one. If anyone has found a solution, I'd love to hear! - Conal ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Those damned parentheses
On 10 May 2011, at 08:30, Yitzchak Gale wrote: If I were to describe to someone in words what this function does, I would say something like: Apply Main.id, turn it into a string, tack a message onto the end, and print it. So why not write it that way in Haskell? Why not indeed ? (--) = flip (.) f = Main.id -- show -- (++ = message received) -- putStrLn ;-) One of the nicest features of Haskell is that the combinator approach is often so natural. :-) :-) Regards, Yitz ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell IDE
On 3 Mar 2011, at 07:05, Hauschild, Klaus (EXT) wrote: Hi Haskellers, whats your Haskell IDE of choise? Currently I use leksah. Is the EclipseFP Plugin for Eclipse a real alternative? WinEdt*/MikTex/GHCi do leksah/EclipseFP support literate haskell programming (mix of .tex and .lhs files) ? * not to be confused with WinEdit ! Thanks Klaus ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I'm still having challenges to get a Haskell GUI to work under Windows 7
On 07/10/2010 19:58, cas...@istar.ca wrote: I'm still having challenges to get a Haskell GUI to work under Windows 7; even after various instructions on the web. e.g. Haskell Platform 2010.2.0.0, wxWidgets-2.9.1, wxHaskell 0.12.1.6 I have seen wxHaskell work on WIndows 7, using the same configuration that works for me on Win XP and Vista (small test program) namely GHC 6.10.4 wxHaskell 0.11.1.2 - uses wxWidgets-2.8.something Installed from binaries. To distribute a useable binary you send around a .exe plus the wxhaskell dll. See http://www.scss.tcd.ie/Andrew.Butterfield/Saoithin/#bin I hope to try this program out on Win 7 later today - I'll let you know how I got on... So unless you really need all the extra goodies of platform 2010, the current fix is to work back to ghc 6.10.4 Similar challenges with GTK+ and gtk2hs. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- --- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Rep. of Ireland. https://www.scss.tcd.ie/Andrew.Butterfield/ --- O ascii ribbon campaign - stop html mail - www.asciiribbon.org ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I'm still having challenges to get a Haskell GUI to work under Windows 7
The windows binaries built using GHC 10.6.4 and wxHaskell 0.11.1.2 on either Win XP or Win 7 work on WIn 7 just fine, except for the font dialog box, which does nothing. This dialog box was a bit flaky on WInXP in any case. I installed 10.6.4 above on WIndows 7 using the binary installer, even though the web-page did not mention WIndows 7 - it seems to work just fine. On 8 Oct 2010, at 09:07, Andrew Butterfield wrote: I hope to try this program out on Win 7 later today - I'll let you know how I got on... Andrew Butterfield andrew.butterfi...@cs.tcd.ie ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I still cannot seem to get a GUI working under Windows.
On 29 Sep 2010, at 20:34, Steve Schafer wrote: This is an attitude that just doesn't fly in the Windows world. Which is unfortunate, because the Windows market is HUGE compared to OS X, and STUNNINGLY HUGE compared to everything else. The fix isn't going to be to find a developer who's willing to do the work to make Haskell+GUI more seamless under Windows. The fix is for the Haskell community--as a whole--to wake up and realize what the wxWidgets folks did a while ago: Hey, you know what? This GUI stuff is _important_ if we want people to pay any attention to the software that we write! This is why, when I developed my theorem prover, I put GUI aspects top of the list I chose wxHaskell because I wanted portability Ironically, given the thrust of this thread, I got it working without too much difficulty on Windows GHC 10.6.4, latest binaries for wxHaskell - easy to install and get working I gather several of my students have successfully done Linux builds of same I switched over recently to Mac OS X (10.6), and (more irony) am having real difficulties getting it to work - installing wxHaskell is a real bear on this platform The GUI theorem prover - see http://www.scss.tcd.ie/Andrew.Butterfield/Saoithin/ (I was going to announce this project to the Haskell Community real soon now, so I guess this is as good a time as any .) -Steve Schafer ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I still cannot seem to get a GUI working under Windows.
On 30 Sep 2010, at 12:02, Serguey Zefirov wrote: 2010/9/30 Andrew Coppin andrewcop...@btinternet.com: And even then, your developed application will only run on Windows boxes that have GTK+ installed (i.e., none of them). You can copy GTK+ DLLs with application. Works fine with wxHaskell as well It works very well. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] RE: Haskell as a first language?
Simon Peyton-Jones wrote: Haskell is a great language! Check out haskell.org. I'm ccing the Haskell Cafe which is read by many people better qualified to answer your question than me. (Since I've been working on Haskell for many years, I am not well qualified to say how it seems to a beginner.) S | -Original Message- | From: Charles Turner [mailto:charlie.h.tur...@googlemail.com] | Sent: 11 July 2009 22:52 | To: Simon Peyton-Jones | Subject: Haskell as a first language? | | I'll make this short! Do you think Haskell is a good language to start | with? I am brand new to programming and have been using Scheme, some of | my peers suggest I should use Haskell. It seems professional to me. | Has features that a beginner should not worry about. What would you | suggest. (I'm not worried about bias) The biggest probelm with full Haskell for beginners is that many type error messages require some familiarity with the class system, which is not a beginner topic.. However, a good starting point perhaps is Helium - a stripped down version of Haskell designed for teaching, with special care gvien to producing useful helpful error messages... http://www.cs.uu.nl/wiki/Helium Then full Haskell could be introduced in semester 2/ year2 / whatever timeline suits (Anything is better than Java.. sigh ;-) | | Thank you very much for your time. | | Charles Turner. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Timing pure functions?
Magnus Therning wrote:
timeIt times ioa = let
timeOnce = do
t1 - getCPUTime
a - ioa
t2 - getCPUTime
let t = fromIntegral (t2-t1) * 1e-12
return t
in sequence $ take times $ repeat timeOnce
main = do
fh - openBinaryFile /dev/urandom ReadMode
d - liftM BS.unpack $ BS.hGet fh 10
t - timeIt 10 $ return $! B64.encode d
print t
I suspect that it all comes from `B64.encode d` being pure, hence the
encoding happens only once. Now I _really_ want the encoding to
happen 10 times, is there some easy way to achieve this?
A quick answer - not a lot of thought - pass function *and* argument
separately into timeIt ?
timeIt times ioaf ioaarg
a - ioaf ioaarg
As it stands you pass the thunk (B64.encode d) in so it only gets
evaluated once
If you pass the function and argument in then a new thunk is built each
time around
(unless the optimiser nabbles it...)
/M
[1]: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/timeit
[2]:
--
Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204
Foundations and Methods Research Group Director.
School of Computer Science and Statistics,
Room F.13, O'Reilly Institute, Trinity College, University of Dublin
http://www.cs.tcd.ie/Andrew.Butterfield/
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Re: [Haskell-cafe] Re: ANNOUNCE: WinGhci, a GUI for GHCI on Windows
Benjamin L.Russell wrote: This is wonderful--just what I was waiting for! The application looks beautiful, and I'm very happy that GHCi now has a matching GUI application along the lines of WinHugs. Indeed - me too ! It would be even better if you could provide some installation/uninstallation information. I unzipped the contents of WinGhci-1.0-bin.zip into the C:\Documents and Settings\username\My Documents\ folder, but there was no README file. And version information - I tried it with GHC 6.4 and it died (Not Responding) What version of GHCi does it require? And no, I won't upgrade GHC just yet (this is the latest GHC/wxHaskell combo that works for me with GHCi...) -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] type metaphysics
Martijn van Steenbergen wrote: To my naive mind this sounds suspiciously like the set of all sets, so it's too big to be a set. Here you're probably thinking about the distinction between countable and uncountable sets. See also: http://en.wikipedia.org/wiki/Countable_set No - it's even bigger than those ! He is thinking of proper classes, not sets. http://en.wikipedia.org/wiki/Class_(set_theory) -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Password hashing
someone asked: What can be used for generating a random salt? Is System.Random secure enough? Achim Schneider wrote: ...or by pinging a random host and taking the time difference, checking the current cpu temperature and fan speed, counting how many times your process gets suspended in a certain amount of time, taking a picture of a lava lamp and hashing it, booting windows, not doing anything, and measure the time it takes to crash, hashing a snapshot of the slashdot frontpage, and, last, but not least, measuring the amount of spam per second currently swooshing into your mail account. or http://www.random.org/ perhaps ? -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] I/O without monads, using an event loop
Robin Green wrote: I have been thinking about to what extent you could cleanly do I/O without explicit use of the I/O monad, and without uniqueness types (which are the main alternative to monads in pure functional programming, and are used in the Concurrent Clean programming language). Suppose you have a main event handler function, like this: eventMain :: (Event, SystemState AppState) - (Command, SystemState AppState) This function could be called over and over in an event loop, until an EndProgram command was received, and the event loop would itself do all the actual I/O (the SystemStates are only in-memory representations of some part of the system state, plus the application's own state). Things like disk I/O could be done with commands which generate events when complete. Interprocess communication could be done in the same way. Then eventMain, and everything called by it, would be referentially-transparent, and yet non-monadic. You could of course build higher-level stuff on top of that. Given the above, without uniqueness typing, and because there is clearly no monad, I could write breakMain :: (Event,Event,SystemState AppState) - ((Command,SystemState AppState),(Command,SystemState AppState)) breakMain (e1,e2,sys) = ( eventMain (e1,sys) , eventMain (e2,sys) ) Now what happens? Do we get two copies of SystemState ? Simpler still, I can write (sys,eventMain e sys) -- what happens here? I have references to both before- and after- state. It is this probelm with copying the un-copiable (external I/O state), that requires pure functional languages to outlaw such programs, either via uniqueness typing, or via a monad interface that completely hides any direct reference to the underlying state and which then sequences the application of state transformers. -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. School of Computer Science and Statistics, Room F.13, O'Reilly Institute, Trinity College, University of Dublin http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Wumpus World
Benjamin L. Russell wrote: Not all students and researchers can afford a Personal License. Can you recommend an alternative, fast Prolog development system under a free licensing agreement, such as GPL/GLPL? For Mac users, https://www.cs.tcd.ie/open-prolog/ might be worth a look ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Mutable arrays
Stefan O'Rear wrote: On Wed, Feb 06, 2008 at 08:57:43PM +, Andrew Butterfield wrote: In Clean, we not only have explicit access to the world, but we can partition it. Simplifying somewhat, we could open up pairs of file-handle (f1.in,f1.out), (f2.in,f2,out) ... (fn.in,fn.out), which does have to be done sequentially, since each file opening modifies the (global) filesystem. However, once this is done, we could, in principle, execute the fn in any order, and indeed in such a way that the implementation could choose to do them in parallel - this potential for (admittedly limited) deterministic parallel execution of I/O actions is possible with uniqueness types, but not epxressible in the monadic world as currently formulated. What if f1.out is a symlink to f2.out? I don't think Clean satisfies the evaluation order independance that is so treasured here. Sorry for lateness in getting back - it's been one of those fortnights.. The case you mention won't arise simply because during the process of opening these file-handles (which cannot be done in parallel, because they all modify the filesystem), the write conflict will be detected, and the opening of the second one will fail. Once the file-handle pairs are all opened we have a guarantee that all writes are to distinct files. -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. Course Director, B.A. (Mod.) in CS and ICT degrees, Year 4. Department of Computer Science, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Ireland. http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: A question about monad laws
Andrew Butterfield wrote: let m denote the list monad (hypothetically). Let's instantiate: return :: x - [x] return x = [x,x] (=) :: [x] - (x - [y]) - [y] xs = f = concat ((map f) xs) Let g n = [show n] Here (return 1 = g ) [1,2,3] = [1,1,1,1,1,1] but g[1,2,3] = [1,2,3], thus violating the first monad law | return http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:return a = http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:gt;gt;= f = f a I messed this up - I was trying for the simplest example I could get ! Apologies. Start over: Program module BadMonad where import Monad newtype MyList t = MyList [t] instance Show t = Show (MyList t) where show (MyList xs) = show xs unmylist (MyList xs) = xs myconcat xs = MyList (concat (map unmylist xs)) instance Monad MyList where return x = MyList [x,x] (MyList xs) = f = myconcat ((map f) xs) i2s :: Int - MyList Char i2s x = MyList (show x) m = i2s 9 Hugs transcript BadMonad m 9 :: MyList Char BadMonad m = return 99 :: MyList Char We violate the second law (Right Identity, m = m = return ) -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. Course Director, B.A. (Mod.) in CS and ICT degrees, Year 4. Department of Computer Science, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Ireland. http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: A question about monad laws
apfelmus wrote: Deokjae Lee wrote: Tutorials about monad mention the monad axioms or monad laws. The tutorial All About Monads says that It is up to the programmer to ensure that any Monad instance he creates satisfies the monad laws. The following is one of the laws. (x = f) = g == x = (\v - f v = g) However, this seems to me a kind of mathematical identity. If it is mathematical identity, a programmer need not care about this law to implement a monad. Can anyone give me an example implementation of monad that violate this law ? I will be mean by asking the following counter question: x + (y + z) = (x + y) + z is a mathematical identity. If it is a mathematical identity, a programmer need not care about this law to implement addition + . Can anyone give me an example implementation of addition that violates this law? Hugs 1.0 + (2.5e-15 + 2.5e-15) 1.01 :: Double Hugs (1.0 + 2.5e-15) + 2.5e-15 1.0 :: Double Hugs, on Pentium 4 machine running Windows XP SP2 (all of which is largely irrelevant!) This is precisely Jerzy's point - you can have many mathematical laws as you like but there is no guarantee that a programming languages implementation will satisfy them. The above example is due to rounding errors and arises because the Double type in Haskell (or C, C++, whatever) is a finite (rational) approximation to real numbers which are infinite (platonic) entities. Associativity of addition applies for platonic reals, but not their widely used IEEE-standard approximate implementation on standard hardware. For monads, the situation is slightly different. Haskell describes the signature of the monadic operators return :: x - m x (=) :: m a - (a - m b) - m b but cannot restrict how you actually instantiate these. It admonishes you by stating that you should obey the relevant laws, but cannot enforce this. (of course, technically if you implement a dodgy monad, its not really a monad at all, but something different with operators with the same name and types - also technically values of type Double are not real numbers, (or true rationals either !) let m denote the list monad (hypothetically). Let's instantiate: return :: x - [x] return x = [x,x] (=) :: [x] - (x - [y]) - [y] xs = f = concat ((map f) xs) Let g n = [show n] Here (return 1 = g ) [1,2,3] = [1,1,1,1,1,1] but g[1,2,3] = [1,2,3], thus violating the first monad law | return http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:return a = http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:gt;gt;= f = f a | Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. Course Director, B.A. (Mod.) in CS and ICT degrees, Year 4. Department of Computer Science, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Ireland. http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Mutable arrays
.in,f2,out) ... (fn.in,fn.out), which does have to be done sequentially, since each file opening modifies the (global) filesystem. However, once this is done, we could, in principle, execute the fn in any order, and indeed in such a way that the implementation could choose to do them in parallel - this potential for (admittedly limited) deterministic parallel execution of I/O actions is possible with uniqueness types, but not epxressible in the monadic world as currently formulated. (3) Shameless plug : a semantics for I/O that covers both Clean and Haskell and which scopes out the deterministic parallelism alluded to above was described in Malcolm Dowse, Andrew Butterfield: Modelling deterministic concurrent I/O. ICFP 2006: 148-159 http://doi.acm.org/10.1145/1159803.1159823 -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. Department of Computer Science, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Ireland. http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Mutable arrays
Peter Verswyvelen wrote: So you say uniqueness typing might be more general… Can one make list monads and all the other funky Haskell monads with Clean’s uniqueness typing then? As my long post pointed out - as far IO is concerned, Clean is more general than Haskell (less over-sequencing). However in a general setting, monads are very general, much more so than Clean's I/O uniqueness types. Monads capture a fundamental pattern of sequential side-effecting computation in a pure referentially transparent way - IO is just a specific instance of this. Having said that, it's worth noting that list and maybe monads can be introduced in Clean, but these would have nothing to do with the I/O infrastructure in that language. -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. Department of Computer Science, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Ireland. http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] using an external application
On 11/2/07, Petr Hoffmann [EMAIL PROTECTED] wrote: import System.Cmd main = do System.Cmd.system echo hello output.txt -- use the external application to create an output file o1 - readFile output.txt System.Cmd.system echo bye output.txt -- the second call to the external application o2 - readFile output.txt putStr o1 -- hello expected, but bye printed return 0 Can you please give me some hint to solve this problem? I'm a beginning haskell developer and I'm still a bit confused by the IO monad. I'm puzzled - when I run this on GHCi (v6.4, Windows XP) I get the following outcome *Mainmain The process cannot access the file because it is being used by another process. hello *Main This is certainly the behaviour I would expect - seeing bye being printed seems to me to be an error and may even constitute a violation of referential transparency. What implementation of GHC are you using ? This looks like yet another case of the lazy-I/O goblins. Yes, but not quite what everyone has being addressing -- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. Course Director, B.A. (Mod.) in CS and ICT degrees, Year 4. Department of Computer Science, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Ireland. http://www.cs.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: OCaml list sees abysmal Language Shootout results
At 03:08 PM 07/10/2004 +0100, MR K P SCHUPKE wrote: I though clean was always strict, and that was the major difference between clean and haskell (that and the fact clean is a proprietry language) No - Clean is pure and lazy like Haskell, - the key difference is that it uses uniqueness types rather than monads to ensure the I/O is referentially transparent and safe. Keean. ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe Dr. Andrew Butterfield (http://www.cs.tcd.ie/Andrew.Butterfield/) Course Director, B.A. (Mod.) Information Communications Technology Dept.of Computer Science, Trinity College, Dublin University Tel: +353-1-608-2517, Fax: +353-1-677-2204 ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
