On 2006-10-17 at 16:31+0200 "Andreas Marth" wrote:
> How was that with Haskell and Unicode???
I think this probably belongs on ghc-users rather than
Haskell.
Anyhow, there aren't any ASCII characters higher than 127.
> While up to ghc-6.4.2 the following function worked it now doesn't compile:
>
On 2006-09-20 at 21:19+0200 "Niklas Broberg" wrote:
> A mailing list will never be enough.
Really?
> A forum has way way more potential.
More potential than what we have already: http://dir.gmane.org/gmane.comp.lang.haskell.general >?
Jón
--
Jón Fairbairn Jon.Fai
On 2006-05-20 at 11:58EDT Robert Dockins wrote:
> On Saturday 20 May 2006 06:53 am, Jon Fairbairn wrote:
> > Make allows one to set up rules about what depends
> > on what, so why can't we just arrange it so that someone who
> > wants to install the thing just hast to
On 2006-05-20 at 12:00+0200 "Sebastian Sylvan" wrote:
> A quick sales pitch: usually you, the library user, can just type:
>
> ./runhaskell Setup.hs configure
> ./runhaskell Setup.hs build
> ./runhaskell Setup.hs install
>
> And it will Do The Right Thing(TM), which is nice.
This is something I'
On 2006-03-17 at 06:58GMT Aaron Denney wrote:
> On 2006-03-17, Donald Bruce Stewart <[EMAIL PROTECTED]> wrote:
> > Well, there is a way -- it's fairly easy with the right regex -- but
> > is it really ambiguous? Do people find it confusing? What do other sites do?
>
> Why not the ISO standard YYY
On 2005-11-14 at 10:38EST John Peterson wrote:
> If someone sends me a new css file I'll be happy to throw it on
> haskell.org for you. Please send an email to this list if you want to
> do this so nobody else wastes their time.
Is anything more needed than the attached patch?
If so, I'm willing
On 2005-11-14 at 11:13+0100 Wolfgang Jeltsch wrote:
> Maybe I changed Konqueror's font settings already. The point is that my
> settings are in such a way that text with the default font size is well
> readable while not taking up too much space. The problem is with
> haskell.org's links. The
On 2005-10-04 at 00:01EDT Mike Crowe wrote:
> Hi folks,
>
> I ran across Haskell at the Great Win32 Computer Language Shootout. A
> friend approached me with a potential large application to develop. The
> idea of a language which can reduce time to design and make better code
> is very intri
On 2005-07-15 at 10:49+0200 Tomasz Zielonka wrote:
> But you can format it this way:
>
> let a very long definition of "a" =
> and the body has to be here is a very long application to "and"
> but using long arguments like definition is not that bad
> in
or
>
> let a very long
1) If another language has a feature, add it to Haskell, so
that absolutely everything can be done in more than one
way. This allows people to write Haskell programmes
without going through the tiresome process of learning
Haskell.`
2) Overload the syntax so that the Hamming dist
On 2005-02-28 at 23:10EST Jim Apple wrote:
> Jon Fairbairn wrote:
> > If you allow quantification over higher
> > kinds, you can do something like this:
> >
> >d f = f . f
> >
> >d:: âa::*, b::*â*.(b a â a) â b (b a)â a
> >
>
> Wha
On 2005-02-28 at 18:03GMT Ben Rudiak-Gould wrote:
> Pedro Vasconcelos wrote:
> >Jim Apple <[EMAIL PROTECTED]> wrote:
> >>Is there a type we can give to
> >>
> >>y f = f . f
> >>
> >>y id
> >>y head
> >>y fst
> >>
> >>are all typeable?
> >
> >Using ghci:
> >
> >Prelude> let y f = f.f
>
On 2005-01-24 at 16:32MST Surendra Singhi wrote:
> Is there any ilisp or slime like package for haskell, which integrates
> haskell with xemacs or emacs and provides a kind of integrated
> development environment?
> I am using Hugs 98.
Does http://www.haskell.org/pipermail/haskell/2004-November/
On 2004-11-04 at 16:16+0100 Koen Claessen wrote:
> Benjamin Franksen wrote:
>
> | 1) I strongly disagree with ideas to execute IO actions
> | implicitly in whatever defined or undefined sequence
> | before or during main for whatever reasons.
>
> I agree with the objections you make. Having fu
On 2004-10-12 at 12:53+0200 Johannes Waldmann wrote:
> this is slightly off topic - I am preparing for a lecture on domain
> specific languages and I try to track down the source and original
> version of (what I recall as) Wadler's "law" of language design,
I think it first appeared here:
http:
On 2004-10-06 at 10:37CDT "ldou" wrote:
> In the random selection, it perhaps select the same element
> of the string, how can I select two different elements?
Consider the \\ operator.
--
Jón Fairbairn [EMAIL PROTECTED]
_
On 2004-06-10 at 10:39BST Martin Escardo wrote:
> Dear Haskell-list members,
>
> This is to advertise the monograph
>
> Synthetic topology of data types and classical spaces, to appear in
> ENTCS 87, 150pp, three parts, 6+5+2 chapters.
Interesting. But why do you use Int rather than the Intege
On 2003-11-18 at 10:46EST "Abraham Egnor" wrote:
> The classic way to write a lift function for tuples is, of course:
>
> liftTup f (a, b) = (f a, f b)
>
> which has a type of (a -> b) -> (a, a) -> (b, b). I've been wondering if
> it would be possible to write a function that doesn't require the
On 2003-08-29 at 17:39PDT Hal Daume III wrote:
> Hi fellow Haskellers,
>
> I'm attempting to get a sense of the topology of the Haskell
> community. Based on the Haskell Communities & Activities reports, it
> seems that the large majority of people use Haskell for Haskell's sake.
>
> If you use
On 2003-08-02 at 14:36PDT "Dominic Steinitz" wrote:
> Could someone explain to me why this doesn't work
>
> test l =
>hs
> where
> hs = map (\x -> [x]) [0..abs(l `div` hLen)]
> hLen = length $ head hs
>
> whereas this does
>
> test l =
>hs
> where
>
On 2003-07-17 at 09:08+0200 Johannes Waldmann wrote:
> On Wed, 16 Jul 2003, K. Fritz Ruehr wrote:
>
> > I think the cutest way to get what you want here is to define a new
> ^^
> > operator as follows:
> >
> > (.<) = (.) . (.)
>
> Indeed this is cute - but let me add a gene
On 2003-07-12 at 20:20+1000 Andrew J Bromage wrote:
> G'day all.
>
> On Fri, Jul 11, 2003 at 04:28:19PM -0400, Dylan Thurston wrote:
>
> > Don't be silly [...]
>
> Never!
Or only sometimes. I'm surprised that no-one has yet
answered the question "How overload operator in Haskell?"
with "Overloa
On 2003-06-17 at 20:15EDT Derek Elkins wrote:
> The closest function I see is ap :: Monad m => m (a -> b) -> m a -> m b
> (so you could write your function as f fs a = ap fs (return a) not that
> I would recommend it). Also you may want to check out the Haskell
> reference at zvon.org, it's indexe
On 2003-06-08 at 18:03PDT Ashley Yakeley wrote:
> In article <[EMAIL PROTECTED]>,
> [EMAIL PROTECTED] (Peter G. Hancock) wrote:
> > Thanks! It made me wonder what colour the sky is on planet Haskell.
> > From a Curry-Howard point of view, (I think) the quantifiers are
> > currently the wrong wa
On 2003-06-06 at 08:15BST "Simon Peyton-Jones" wrote:
>
> I forget whether I've aired this on the list, but I'm
> seriously thinking that we should change 'forall' to
> 'exists' in existential data constructors like this one.
You did mention it, and there were several replies. I'd
characterise th
On 2002-10-29 at 04:09PST Ashley Yakeley wrote:
> At 2002-10-29 03:42, Jon Fairbairn wrote:
>
> >But we could just make $ the primitive instead of
> >juxtaposition (and infix the primary form).
> >
> >Then f a is shorthand for f $ a and it stops there.
>
> But
On 2002-10-29 at 03:21PST Ashley Yakeley wrote:
> At 2002-10-29 02:43, Josef Svenningsson wrote:
>
> >> I'm pretty sure it's not possible...
> >>
> >You mean in H98? Sure no! What I meant was to implement overloading of
> >function application as an extension of H98.
>
> See my earlier message. I
> Alain Cremieux wrote:
> I am trying to build a functional firewall generator. The first part
> describes the available protections (kernel, anti-address spoofing, etc.).
> The second desribes every protocol, and the necessary rules if the
> corresponding service is enabled (e.g. open the http po
> Jon Fairbairn <[EMAIL PROTECTED]> writes:
>
> > data Port = Tcpmux | Nbp | Echo_ddp | Rje | Zip | Echo_tcp | ...
> > deriving Enum, ...
> > instance Num Port where ...
>
> Or, alternatively, just use Strings, and have a portFromString first
>
> Hi,
> I am trying to create an overloaded function "à la Java" to be able to
> call it either with a string or a number.
> Ex :
> definePort "http"
> definePort 80
> but I have problem with restrictions in Haskell's type system
> Is there a better solution ?
If we knew /why/ you wanted to do t
Apologies for responding to messages in reverse order . . .
> * My reluctance to change the draft H98 report is rising sharply.
Understood!
> * I don't think the H98 report has ever had laws about mzero etc.
No, they went on the transition from 1.4, I think.
> * And the whole laws business i
> On Fri, Jun 21, 2002 at 12:50:21PM +0100, Simon Peyton-Jones wrote:
> > | From: Jon Fairbairn [mailto:[EMAIL PROTECTED]]
> > | Sent: 20 June 2002 16:27
> > | To: Simon Peyton-Jones
> > | Subject: Library report, monad zero laws
> > |
> > | The old
> Paul Graham is collecting canonical accumulator generators at
> http://www.paulgraham.com/accgen.html , and has Dylan, E, JavaScript,
> various dialects Lisp, Lua, Rebol, Ruby, Perl, Python and Smalltalk.
As others have implied, the only correct answer to this is
"it's the wrong question". One
I wrote:
> > Can someone remind me why the "A close brace is also inserted whenever
> > the syntactic category containing the layout list ends" part
> > of the rule is there?
Lennart wrote:
> It's so you can write
> let x = 2+2 in x*x
> (and similar things)
and Arjan van IJzendoorn wrote:
> >Yes you can define it,
>
> And you can, as well.
Man sollte sich nicht darauf verlassen, daß ein Englander
"man" verwendet, wenn es angebraucht wäre¹.
> That's how common idioms come into being;
> there's no special magic about the folds already in existence.
Well, my point is that there i
> I like layout but I think the existing rules are too
> complicated. Unfortunat ely it's difficult to do anything
> with them without breaking vast swathes of existing code,
> so we'll just have to put up with them.
Well, there's two things to consider: Haskell 98, which
probably shouldn't chan
> Hey Simon et al at Micro$oft, when will there be an H#?
But H# is C! we don't want that, surely? :-)
Jón
--
Jón Fairbairn [EMAIL PROTECTED]
31 Chalmers Road [EMAIL PROTECTED]
Cambridge CB1 3SZ+44 1223 57017
Two very similar programmmes:
> possible_int = do skip_blanks
> fmap Just int
>+++ (literal "-" `as` Nothing)
> possible_int = do skip_blanks
> fmap Just int
> +++ (literal "-" `as` Nothing)
I think this is extremely ba
> foldr, foldM, etc. derive a recursive computation from the
> recursive structure of an input list, so you have to feed
> one in. If you want to bypass the list, you could use
> IO-observations (getLine, isEOF) instead of list
> observations (head/tail, null):
Yes you can define it, I should ha
Suppose I have a task I want to do to each line of a file,
accumulate a result and output it, I can write
main = do stuff <- getContents
print $ foldl process_line initial_value (lines stuff)
ie, it's obviously a fold
I can't see a way of doing the same thing directly on the
IO
"Dominic Steinitz" <[EMAIL PROTECTED]> wrote:
> I've managed to crack something that always annoyed me when I used to do
> network programming.
[. . .]
>
> Suppose I want to send an ICMP packet. The first byte is the type and the
> second byte is the code. Furthermore, the code depends on the typ
On Tue, 2 Apr 2002 10:00:37 +0200 (MET DST), John Hughes
<[EMAIL PROTECTED]> wrote:
> >If (as a human reader of a programme) I see
> >
> >do a <- thing1
> >
> >
> >and I notice (perhaps after some modifications) that a is
> >not present in , then I /rea
Wolfgang Jeltsch <[EMAIL PROTECTED]> wrote:
> It shouldn't be syntactic suger but at most an operator which does not belong
> to the monad class. One could define (>>) just as an ordinary function
> instead of a class member.
That sounds to me like the best idea so far.
If (as a human reader of
> On Wed, Mar 20, 2002, Jon Fairbairn wrote:
> > > Could someone post an example of the creation of a
> > > temporary file where race conditions are important?
> >
> > /any/ programme that does this on a multi-process system.
>
> Occasionally, the prese
> Thanks for all the advice. In the end, I couldn't make $! work for me
> (it always seems to be harder than I think it will be to use it, and $!
> and deepSeq makes my code run slowly).
:-(
> But a continuation passing style foldl worked wonderfully.
As Jay Cox pointed out by email, my answ
> Could someone post an example of the creation of a
> temporary file where race conditions are important?
/any/ programme that does this on a multi-process system.
Between the test for existence and the creation, some other
process could have created a file of the same name. Then
the create fai
> Apologies for the typo: that should have been 5 elements, not 500.
>
> Amanda Clare wrote:
> > I have stack problems: my program uses too much stack. I suspect, from
> > removing bits of code, that it's due to a foldr in my program. If I use
> > foldr or foldl on a long list (eg >500 bulk
> There's a remark at the beginning of 7.2 that says:
>
> delete, (\\), union and intersect preserve the invariant=20
> that lists don't contain duplicates, provided that=20
> their first argument contains no duplicates.
>
> The same applies to unionBy etc. This design is one
> you might reaso
The current library report defines unionBy like this:
unionBy eq xs ys = xs ++ deleteFirstsBy eq (nubBy eq ys) xs
why does it take the nub of ys, but not xs? I'd have expected
unionBy eq xs ys = (nubBy eq xs) ++ deleteFirstsBy eq (nubBy eq ys) xs
Jón
--
Jón Fairbairn
"Rijk J. C. van Haaften" <[EMAIL PROTECTED]>
wrote:
> Recently, I wrote a function similar to
>
> x :: a
> x = x 42
>
> which is type-correct (Hugs, Ghc, THIH).
> Still, from the expression it is clear
> that the type shoud have a function type.
> The definition
>
> x :: a -> b
> x = x 42
>
>
> > I argued that (Num a, Ord a) makes most sense to me.
> > You argued that (Integral a) was a conscious choice (something I
> > don't remember but I'm sure you're right), and is the right one anyway.
> >
> > I'd be interested to know what others think. If there's any doubt,
> > we'll stay with
> At 2001-11-01 22:10, raul sierra alcocer wrote:
>
> >What mechanism of transmiting parameters does Haskell implement?
>
> By value.
Yes, though one might equally say that they are passed by
reference, since in
g = let f x = x+x
z = factorial 1000
in f z * z
the 'first' instance
> On Tuesday 16 October 2001 07:29, Fergus Henderson wrote:
> > [...]
> > The whole idea of letting you omit method definitions for methods with
> > no default and having calls to such methods be run-time errors is IMHO
> > exceedingly odd in a supposedly strongly typed language, and IMHO ought
>
> > The lexical syntax says that
> > 10e3
> > means
> > 10 e3
> > (i.e. two lexemes). I don't like this choice, and it could be "fixed"
> > in the Revised H98 report.
>
> What is the likelihood of anyone *intentionally* writing an integer
> abutted directly with a varid, followed direct
> > hello, i just want to ask a simple question: does
> > somebody have or knowwhere to find a haskell program that
> > calculates the number e, that is the list of infinite
> > digits?
> It's a nice problem, which I encountered many years
> ago as one of the first examples I saw of lazy e
Unless I'm mistaken, foldl' (the strict version of foldl)
doesn't appear in (the export list of) the standard prelude
or the list library.
Is there a good reason for this? New users quite quickly
find that they need it.
Jón
--
Jón Fairbairn [EMAIL PROTECTED]
3
> and not just type systems but also other aspects of operational
> semantics. What we have here is a single rule from a rule-based
> inductive definition of a certain relation G |- s :: S between typing
> environments G, expressions s and types S.
It's probably worth mentioning here that this n
Ashley Yakeley <[EMAIL PROTECTED]> wrote
> OK, I understand it a bit better now. This code does not compile:
> --
> class X a
> instance X Bool
> instance (Num a) => X a
> --
> Can someone explain why the two instances overlap, given that Bool is not
> an instance of Num?
>
> Would it be possibl
On Sun, 21 Jan 2001, David Bakin wrote:
> This article is very good, and having read the conference paper earlier
> in the year I finished it with only one question: What's a 'quant' ...
> and is it good or bad to be one?
>
> "Ten years ago, Jean-Marc Eber, then a quant at Société
> Gén
On Wed, 17 Jan 2001, Koen Claessen wrote:
> I propose that it gets the following fixity:
>
> infixl 5 \\
Unless the it's common usage outside of Haskell, I oppose!
Getting
List> [1,2,3]\\[2]\\[3]
ERROR: Ambiguous use of operator "(\\)" with "(\\)"
at compile time does no harm, but ge
On Fri, 1 Dec 2000, Zhanyong Wan wrote:
>
> Ronald Kuwawi wrote:
> >
> > open text editor, type
> > hash :: [Char] -> Int
> > hash = (foldl (+) 0) . (map ord)
> hash "HASKELL%98"
hash "Haskell Ninety Eight !!"
surely?
--
Jón Fairbairn [EMAIL PROTECTED]
__
> If you define `p' as a syntactic function, e.g.
>
> p x y = x + y
> or
>
> p x = (+) x
>
> rather than via
>
> p = (+)
>
> then the monomorphism restriction does not apply, and so the type inferred
> for `p' will be the correct polymorphic type `Num a => a -> a -> a'.
Ma
> No, but they ARE, assuming IEEE arithmetic,
which is what the Report says, isn't it.
> discrete mathematical objects with an arithmetic as well
> defined as that on the integers. To do constant folding
> according to different rules is, IMHO, outrageous.
yes
> Surely this is obvious to Has
Lennart Augustsson wrote:
> Frank Atanassow wrote:
> > 2) The Prelude doesn't use it.
>
> Well, it doesn't for historical reasons.
Am I alone in thinking that the prelude is desperately in
need of restructuring? Has anyone got any proposals for
nested modules (so we could have Prelude.List.
> Me too, for (A)! (B) looks too ugly for me. A type declaration should
> refer to the "most local" definition of the name.
I go for A, though I'd say that type declarations are part
of the definitions and the definitions in a module
obviously are of names in that module.
> Btw, why would on
I'm reluctant to get involved in this discussion, cheifly
because it seems to me that Jan is attacking a position that
has quite a long history with (inter alia) the argument that
a different position has a longer history, which doesn't
strike me as terribly likely to lead to insight.
Also my pr
> Then, the question is why we write
> result = function operand1 operand2
> instead of
> operand1 operand2 function = result
>
> I actually think the latter is cooler. :)
I think there may be cultural influences about word order and/
or writing direction creeping in here :-)
--
Jón Fairba
> > Take and drop
> > [..]
> > I can see three alternatives:
> >
> > (A) Make them defined for any n. If n < 0, do something reasonable:
> > take: give empty list
> > drop: give whole list
> >
> > (B) Make them defined for n > length xs, but fail for n < 0.
> >
> > (C) Status quo
> >
>
> Is not deleteBy :: (a->Bool) -> [a] -> [a]
> more natural for the library than
>deleteBy :: (a->a->Bool) -> a -> [a] -> [a]
> ?
I'd say so. In general the prelude seems rather weak on
functions to manipulate predicates.
Jón
--
Jón Fairbai
On 9 Oct, Heribert Schuetz wrote:
[(f <| g) x = f (g x); (f |> g) x = g (f x)]
>"Use symmetric glyphs for commutative operations and asymmetric glyphs
>for non-commutative operations. Reflect glyphs for flipped operations."
That would make me happy.
> which I would suggest as a gener
On 8 Oct, Jonathan King wrote:
> I think you might see the point. (No pun back there, I promise...) I
> understand where using "." to mean composition came from, and I know that
> it's a long-standing tradition in at least the Haskell community, but I
> don't think the visual correspondence
On 8 Oct, Christopher Jeris wrote:
> Personal taste in infix operators seems to be another good argument for a
> camlp4-style preprocessor for Haskell.
Please no! I want to be able to read other folks programmes and vice
versa. The whole point of suggesting a particular glyph on this foram
On 8 Oct, Joe English wrote:
> [I wrote]:
> > Just now I thought of .~ from . for composition and ~ (tilde, but
> > commonly called twiddle) for twiddling the order about.
> I've also seen .| and |. used for this purpose (by
> analogy with Unix pipes.)
> John Hughes' Arrow library spells
Some time ago there was a discussion about what to call reverse
composition (I can't find it in the archive - needs a search option?)
Just now I thought of .~ from . for composition and ~ (tilde, but
commonly called twiddle) for twiddling the order about.
Maybe we could adopt that as normal usag
On 27 Sep, Manuel M. T. Chakravarty wrote:
> Antti-Juhani Kaijanaho <[EMAIL PROTECTED]> wrote,
> > Please don't define lists by who'll use them. Define them by the topic
> > of discussion.
>
> Good point. `haskell-help' or some such is definitely
> better.
'haskell-questions'? Maybe this
On 16 Sep, Keith Wansbrough wrote:
> I suggest calling them "pi13" or "prj13" rather than "tuple31", though.
pi1_3 or proj1_3 or select_1_3 or sel_1_3, even s_1_3 -- omitting the
"_" means sel is ambiguous (!). We should choose a scheme that can
cope with such things even if they are unlikel
On 9 Sep, Christian Sievers wrote:
> It's a good idea to use two different types in an example, but Char
> is not well chosen, because the canonical way to write the above
> result is ("abc",[1,2,3]).
Good point. String is best:
unzip [("a", 1), ("b", 2), ("c", 3)] = (["a", "b", "c"], [1, 2,
On 9 Sep, George Russell wrote:
> Here is my revised version of the documentation.
my :-) (which incorporates some of the other suggestions.)
I've given reasons at the bottom.
Type:
> unzip :: [(a,b)] -> ([a],[b])
unzip takes a list of pairs and returns a pair of lists.
Definition
On 8 Sep, George Russell wrote:
> Don't add more functions like concatSep to the standard library or prelude.
Certainly not to the prelude, but I think there is a strong case for
evolving the standard library based on what people use. I use
((concat .) intersperse) quite a lot, and having a st
On 19 Aug, Mark P Jones wrote:
> [...] note that the error messages that prompted
> Jon's comment didn't have anything to do with sophisticated type systems.
> Dealing with those kinds of things requires some hard work, but it isn't
> research, and so it's hard to justify, at least in an acade
On 20 Aug, Bob Howard wrote:
> data BTree Integer = Leaf Integer | Node Integer (BTree Integer) (BTree Integer)
^
this ought to be a type variable name, but you've put the
name of a type.
> mkTree :: Integer -> BTree
^ arg
On 13 Jul, Wolfram Kahl wrote:
> I confess guilty to have diverged from this simpler problem
>
> > (//) :: [a] -> [b] -> [(a,b)]
>
> to the more general problem
???
like
> diagonalise:: [[a]] -> [a]
> diagonalise l = d [] l
> d [] [] = []
> d acc [] = -- d [] acc w
On 11 Jul, Wolfram Kahl wrote:
> Koen Claessen <[EMAIL PROTECTED]>
> proposes the following diagonalisation function:
> >
> > [ (a,b) | (a,b) <- [1..] // [1..] ]
> >
> > For a suitable definition of (//), for example:
> >
> > (//) :: [a] -> [b] -> [(a,b)]
> > xs // ys =
On 8 Jun, Paul Hudak wrote:
> show x should be a string that when printed looks like the value that
> you would have to type to generate it directly. This example is most
> instructive:
[...]
and this is just cute:
main = putStr (quine q)
quine s = s ++ show s
q = "main = putStr (quine q)\
On 20 May, Frank A. Christoph wrote:
>
> > > I would welcome either. However, there is a huge body of code that
> > > assumes strings are lists of chars.
> >
> > Yes, obviously... this is for new programs (which people aren't writing
> > because of Haskell's inefficiency in dealing with strings
On 20 May, Kevin Atkinson wrote:
> Sorry typo. That should be optional.
Is this a job for overloading? I think it would be better to provide
some syntactig sugar and compile-time checks for something like this:
data Argtype = Arg {a::Int, b::Bool, c::Char}
arg = Arg {a = 1, b = True, c = erro
x27;1'] ++ foo ((x::Int) - 1)
which gives
Main> :type foo
foo :: Int -> [Char]
Main>
or write
foo :: Int -> [Char]
foo 0 = []
foo x = ['1'] ++ foo (x - 1)
to declare it yourself.
Note that type casting in the C sense is not available in Haskell,
the only thing you c
>
> This is a distilled version of a problem that arose in a student's program:
>
> > f :: a -> a
> > f x = g
> >where
> >g :: a
> >g = x
>
> Reading file "[...]":
> Type checking
> ERROR "[...]" (line 5): Inferred type is not general enough
> *** Expression: g
> *** Expected ty
On 27 Nov, Simon Marlow wrote:
> (((+) + 1) + 1) 1 = (+)
I just read this out to a friend, whose response was "Show that sort of
thing to hackers and you'll convert them to functional programming
instantly!"
--
Jon Fairbairn [EMAIL PROTECTED]
r for someone to see that
a --> b
is an expression now. The previous rule was visually confusing.
> Apologies if this is dragging up old arguments.
Likewise!
--
Jon Fairbairn [EMAIL PROTECTED]
able the code"
Me: "!"
> Erik "warrior against the Edith Bunkerizing of programming
Who she?
> languages" Meijer
Jon
* apologies to those not familiar with the British pantomime traditions.
--
Jon Fairbairn [EMAIL PROTECTED]
; 2. I havn't been able to think of anything better than these monsters.
um, monadZero, monadFail? People who can't type can always add their
own renamings.
--
Jon Fairbairn [EMAIL PROTECTED]
default behaviour is safe rather even
if less efficient. When the efficiency hit is significant and the
programmer is sure that Int is safe, Int would be used.
Am I missing the point here?
Jon
--
Jon Fairbairn [EMAIL PROTECTED]
18 Kimberley Road
reed, though I think there is a strong case of providing most of
those operations on Integer too (perhaps at a different type).
--
Jon Fairbairn [EMAIL PROTECTED]
xpressions to be typed at Int.
Overload that too!
Given that the report already mentions the 'specialize' pragma, I
don't see any reason why the newly overloaded functions shouldn't be
accompanied by specialisations for both Integer and Int, which should
remove the efficiency
hat I had in mind. Isn't it also possible to
reduce the number of checks for sequences of operations?
--
Jon Fairbairn [EMAIL PROTECTED]
18 Kimberley Road[EMAIL PROTECTED]
Cambridge CB4 1HH +44 1223 570179 (pm only, please)
uestion is of performance for Int sized things in Integer, so the
fact that you call a good library isn't relevant; what's important is
what you do when you don't _need_ to use GMP to get the answer. My
guess is that most of the real cost of doing Int sized arithmetic in
I
don't compile, it's harmless.
So I don't think either of these experiments would be helpful.
Changing to Integer improves the design of the language and increases
the chance that programmes will give correct results. It's not as if
we are asking for Int to be banned!
J
dashes would be a pain.
only a pain, and only briefly. I contend that it's easier to learn to
write
-- ---
than to learn not to try to define -->, |--, --| and so on. Oh, and what is
{-- comment --}
under the present rules?
Jon
--
Jon Fairbairn [EMAIL PROTECTED]
y
> between the first draft and the next edition. It also resonates
> with those of use who remember Lisp 1.5, which was the `Standard
> Lisp' for many years. -- P
I think I agree; the other alternative would to be literal and call it
Haskell 1 Final, or 1F for short.
--
Jon
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