] http://hackage.haskell.org/package/dlist-0.5
[2] http://semantic.org/hnop/
On Wed, Aug 19, 2009 at 9:45 AM, Jared Updike jupd...@gmail.com wrote:
I compiled and installed haddock-2.4.2 from the tarball source.
Adding a few simple comments to the code here:
https://dl.getdropbox.com/u/143480
I compiled and installed haddock-2.4.2 from the tarball source.
Adding a few simple comments to the code here:
https://dl.getdropbox.com/u/143480/doc/DualMap.hs
and running haddock
$ haddock -h -o doc Data/DualMap.hs
Warning: Data.DualMap: could not find link destinations for:
LOGO VARIATION GENERATOR
With some encouragement and feedback from Jeff Wheeler and Eelco
Lempsink, I created a Polymorphic SVG Haskell Logo in Haskell [1].
This script yields a pile of SVG files and an HTML index showing them
off (known to work in Safari 3.0 and Firefox 2.0) [1]:
' (e.g. in the subject).
Depending on the winner of this voting round we can decide whether we need
to continue with variations. Jared Updike already offered to donate a bit
of time to help create several variations. But for now, good luck with
sorting those options! :)
--
Regards
I agree that we should use the first round of voting to learn what the
general consensus of the Haskell community is on a logo design idea
(and to filter out the non-viable logos).
In the spirit of bikeshedding, I would love to see---and would
volunteer to spend part of a day editing, say, the
I had a similar thought. That will probably do the trick.
Jared.
On 2/8/09, Svein Ove Aas svein@aas.no wrote:
On Mon, Feb 9, 2009 at 8:02 AM, Jared Updike jupd...@gmail.com wrote:
It looks like two Map.splits will do what I need except for allowing
more exact testing of = vs
visit all of them before it
enumerated the ones that satisify the predicate. I don't believe
laziness would help here.
HTH,
Anish
On Sun, 08 Feb 2009 23:02:37 -0800, Jared Updike jupd...@gmail.com wrote:
It looks like two Map.splits will do what I need except for allowing
more exact
On 2/8/09, Evan Laforge qdun...@gmail.com wrote:
I have a little util library with various map functions. 'within' is
almost what you want, except it's half-open. You can make an
inclusive one by pulling the lowest element off the above map.
I'm also curious if there's a better way to do
I would like to enumerate a subset of keys in a Map satisfying \ key
= key1 key = key2 but in the expected, reasonable amount of time
(e.g. O(log(n)) + O(m) for n total keys and m keys in the subset).
(Or key key1 and/or key key2 or some such combination).
Is there an appropriate idiom or
It looks like two Map.splits will do what I need except for allowing
more exact testing of = vs. (since == elements are left out of both
maps...?)
Jared.
On 2/8/09, Jared Updike jupd...@gmail.com wrote:
I would like to enumerate a subset of keys in a Map satisfying \ key
= key1 key = key2
I'm interested in using Functional MetaPost on Mac OS X (or FreeBSD).
I'm looking for a tutorial like:
http://haskell.org/haskellwiki/Haskell_in_5_steps
but for FMP. I can't even get a simple example to show up in a PDF file:
---
import FMP
... (see full code below)
myPicture =
If you substitute your mpfr_set_signed_int for the one below, the noworks
should become works.
Yes, this works perfectly. Thank you for saving my project! (Had I
known about HMPFR when I started this project, I would have just used
that instead of rolling my own, but it looks like HMPFR was
In order to create an arbitrary precision floating point / drop in
replacement for Double, I'm trying to wrap MPFR (http://www.mpfr.org/)
using the FFI but despite all my efforts the simplest bit of code
doesn't work. It compiles, it runs, but it crashes mockingly after
pretending to work for a
tell
GHC leave this mess and anything in the C heap completely alone?
Jared.
On 10/5/08, Alexander Dunlap [EMAIL PROTECTED] wrote:
On Sun, Oct 5, 2008 at 5:38 PM, Chris Mears [EMAIL PROTECTED] wrote:
Jared Updike [EMAIL PROTECTED] writes:
Can someone else verify if this is a Mac/BSD
this. Or
just send the code.
Simon
| -Original Message-
| From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
| Behalf Of Jared Updike
| Sent: 03 February 2007 08:17
| To: glasgow-haskell-bugs@haskell.org
| Subject: ghc-6.6: panic! (the 'impossible' happened)
|
| ghc-6.6: panic! (the 'impossible
ghc-6.6: panic! (the 'impossible' happened)
(GHC version 6.6 for i386-apple-darwin):
checkKind: adding kind constraint
t{tv a2M5} [tv] *
t_a1pL{tv} [tau] t_a1pL{tv} [tau] ??
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
---
If you want the
Maybe I've misused the word segfault.
What happened is:
The programme consumed more and more memory (according to top),
kswapd started to have a higher CPU-percentage than my programme,
programme died, system yelling 'Speicherzugriffsfehler', top displays
'kswapddefunct'.
I believe that means my
In C, it wouldn't be, since there, unary ops always bind tighter than infix
ops, and the precedences used in C are also used in C++, Java, C#,
Javascript etc, and even ISO Prolog obeys the rule that unary minus binds
tighter so making unary minus have the same precedence as infix minus just
makes
it was the first imperative language supporting closures, after all
Uh, what about lisp?
For those who read the Foozles slides posted earlier [0], I must say
he nailed this one, on slide 2.
The (MIT) lisp 1.4 manual (ca. 1965) refers to
FUNCTION differing from QUOTE in that it handled free
And stop calling me Shirley.
Could you please be a bit more explicit? Have I offended anyone?
This is a reference to a joke from the movie Airplane:
Surely, you can't be serious.
I am serious, and stop calling me Shirley.
I imagine it meant nothing personal.
Jared.
--
which is close but not exactly as wanted. The meta (and I expect
other tags like br will have the same) tag has closing slash as it
would have in XML (XHTML), but not in HTML. Also the DOCTYPE has been
lost.
I've had similar problems outputting XHTML. For example, naive output
(correct
Just a bit of info on the br, IE treats br/ as a line break, but
br/br as 2 line breaks. Just in case you go for the obvious
solution of always expanding out a/ to a/a, br won't work.
but br / with a space works. And this applies to most tags with
this behavior---the space helps, and it
I think this works:
http://haskell.org/edsl/pansharp.html
Jared.
On 8/23/06, HIGGINS Neil (ENERGEX) [EMAIL PROTECTED] wrote:
Fran is a Haskell library (or embedded language) for interactive
animations with 2D and 3D graphics and sound. See
http://www.conal.net/fran/ and
Now I need to find something else for practice. Is there anything
related to data analysis/statistics that is lacking is Haskell?
A native implementation of multiparameter data fitting (requires some
linear algebra) like:
Sec 15.4 of http://www.library.cornell.edu/nr/bookcpdf.html
or
(Sorry for the late reply; have been on holiday.)
No problem. Your email system was kind enough to say when you'd be back :-)
I've used it to diff fairly large files (hundreds of K's, if not Megs)
where there were few differences. It seemed to perform OK, and in cases
where GNU diff (or
I feel that Haskell is missing some basic string manipuation functions, like
- replacing all occurances of one substring (or sublist) with another
string (or list).
- tokenize a string by an arbitrary delimeter
This came up not too long ago:
I'd have thought it would have been simpler to just make the rule that -2
(no spaces between '-' and '2') would be a single lexeme
I'd have thought so too, until I implemented a parser with exponentiation.
It is easy to get confused and make a parser that is too eager to include
the minus sign
I'd also argue that in maths the necessary brackets are implied by the
superscripting syntax
ASCII text parsing issues aside, in math,
2
-4 =?
(No you cannot ask if there is space between the 4 and the - symbol,
or if I meant (-4)^2 or -(4^2), or if I wrote a negative sign
Yes but my point is that -4^2 is not the same as
2
-4
because the latter by convention means - (4^2).
In other words, superscripts bind tighter than prefix ops but prefix ops
bind tighter than infix.
I see. My point is that there already exists a convention[1]
haskell-cafe@haskell.org is usually a better venue for these sorts of
questions. People there love helping people learn Haskell.
And when I try to load it to GHCi I get an error (there is also plenty of
others but they look the same):
couldn't match Int against t t1
This error occurs because
putStrLn (Product: ++ convertnumbertostring(pp))
Also, there is a predefined function called 'print' where
print x = putStr (convertnumbertostring x)
i.e.
print x = putStr (show x)
Jared.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
Google Scholar is often quite handy for this sort of situation.
http://scholar.google.com/scholar?q=typing-haskell-in-haskell+jones
Jared.
On 8/14/06, Tim Walkenhorst [EMAIL PROTECTED] wrote:
It can be found here: http://citeseer.ist.psu.edu/424440.html
Thanks! Actually I've seen this
http://happs.org/HAppS/README.html
http://pass.net/
Jared.
On 8/9/06, Adam Peacock [EMAIL PROTECTED] wrote:
On 8/10/06, Jared Updike [EMAIL PROTECTED] wrote:
[..]
http://www.ugcs.caltech.edu/~lordkaos/calc.cgi
(source available here http://www.ugcs.caltech.edu/~lordkaos/calc.tar.gz
and also ended up with an STArray based implementation. I can send the
code if you're interested. I have no idea how well it performs compared
to Ian's, or the one in darcs (which uses PackedStrings).
Ian's LCS code looks like it works fine in terms of space usage, but
for large input (lengrh
This would require to:
- Retarget one of the existing Haskell compilers to generate JavaScript
(other possible targets would be Flash or higher level UI languages such as
OpenLaszlo that in turn compiles down to either Flash or JavaScript/HTML)
As I've noticed from experience, you can just
So basically he rediscovered Why FP Matters
(http://www.math.chalmers.se/~rjmh/Papers/whyfp.html) ~15-20 years
after the fact, but neglected to point out the interesting fact that
one can write map in terms of reduce (i.e. foldr) (obviously he didn't
read the paper) and ignored the benefits of
I don't think this commentary is really fair. It's also insular and bad for
the reputation of the Haskell community. There are enough barriers to
exploring FP and Haskell already. The purpose of the article was to
encourage people to start taking baby steps toward FP, not to demonstrate a
deep
On 8/1/06, Mark T.B. Carroll [EMAIL PROTECTED] wrote:
I wanted a longest common subsequence function and a bit of Googling
failed to turn up a functional one, except for in a scary bit of darcs.
I saw a thread from back in the day about this when I was looking for
a good implementation of
This page:
http://jaortega.wordpress.com/2006/03/17/programmers-go-bananas/
lists some references at the bottom. Perhaps they would be useful.
Jared.
On 8/1/06, Brian Hulley [EMAIL PROTECTED] wrote:
Robert Dockins wrote:
[snip other points]
7) Finally, I somehow feel like there should be
Hmmm I found
http://www.haskell.org/haskellwiki/WxHaskell/Installation_tips
so there are two such pages, the other being:
http://www.haskell.org/haskellwiki/WxHaskell/Install
so perhaps these pages can be merged? and a redirect placed from one
to the other?
Cheers,
Jared.
On 7/31/06,
I am trying to derive MyOrd class from Eq (Prelude):
class Eq a = MyOrd a where
(%=), (%), (%=) :: a - a - Bool
x %= y = (x y || x == y)
x % y = y x
x %= y = (y x || x == y)
Q: What's wrong? Why 'Ord' gets into play here?
You are using which is a function
Sorry, left out an important verb, *hide*:
You can the prelude and thus the Ord class and make your own and
You can *hide* the prelude and thus the Ord class and make your own and
Jared.
--
http://www.updike.org/~jared/
reverse )-:
___
GSL Haskell bindings:
http://dis.um.es/~alberto/GSLHaskell/
http://dis.um.es/~alberto/GSLHaskell/doc/
Specifically for Linary Algebra:
http://dis.um.es/~alberto/GSLHaskell/doc/GSL-Base.html
You make a good point and the decision was by no means cut and dry. However
I made a point of
Also, I found that the textbook The Haskell School of Expression by
Paul Hudak is a good introduction (particularly, if I remember
correctly, the second half of the book) to functional reactive
programming in Haskell.
Jared.
On 7/16/06, Nicolas Frisby [EMAIL PROTECTED] wrote:
You might
Did you try putting this in a file, say, t.hsand running
ghci t.hs
then typing
:type func
at the GHCi prompt? It should tell you the function type.
Jared.
On 7/14/06, Jenny678 [EMAIL PROTECTED] wrote:
Hallo
Can somebody tell me the type of the following function?
func ::
(leave off the line with
func :: ???
and the compiler will figure it out for you, if possible---it works in
this case)
Jared.
On 7/14/06, Jared Updike [EMAIL PROTECTED] wrote:
Did you try putting this in a file, say, t.hsand running
ghci t.hs
then typing
:type
fields = csv `separateWith` ,
csv = fields `joinWith` , -- equivalent to concatIntersperse
Hence I would much rather have the split condition be the first
parameter -- the infix notation looks good, but it will need a
flip to get the parameters in the right order.
This also goes along with
split is... unconcatIntersperse.
How about separate? (split or splitBy is better but it is used
all over the place in many libs)
And for strings I definitely would use split :: [a] - [a] - [[a]] a
lot, just like Python's split function. And words works great for
breaking on multiple spaces,
I'm not sure if there is a comprehensive timing summay but here are
some different approaches and code you can compile and run on your
machine:
http://haskell.org/haskellwiki/Sudoku
In fact, if you run them all, you can share your numbers with us and
we can add them to the Sudoku page. And of
Am I the only one whose first instinct upon reading this is EW!?
You are not the only one, judging from my own experience. I made my
own sort of algebraic datatypes / abstract datatypes in C# by using
Enums and Objects and runtime casts. It works, but the code itself is
hairy. I guess the good
I have been trying to understand closures in haskell and how they relate
to side effects. I have been looking around but all I find are trivial
examples with no side effects. Please let me know if you know of any
examples.
Bulat what you mean by 'closure'?
Perhaps you are refering to
On 6/22/06, Greg Buchholz [EMAIL PROTECTED] wrote:
Ralf Hinze wrote:
Also, in a non-strict language recursive definitions are not
limited to function types. Users of parser combinators heavily rely
on this feature. Just try to define/use parsing combinators
ins a strict language.
Anyone
Therefore the list of non-negative integers is longer than the list of
positive integers. I agree they have the same cardinality but this doesn't
mean they have the same length.
Are you saying that some of the (0,1,2,3,4,5,...), (1,2,3,4,5,...) and
(1-1,2-1,3-1,4-1,5-1,...) lists have
On 6/22/06, Sara Kenedy [EMAIL PROTECTED] wrote:
Hello all,
Now I am trying with the function of polymorphic type: This function
returns the Nth element of list with type a. I try it as below.
getNthElem :: Int - [a] - Maybe a
getNthElemt _ []= Nothing
getNthElem 0 _ = Nothing
fromInteger x = [[fromInteger x]]
Wouldn't you want the expression
[[1,0],[0,2]] + 10
to yield
[[11,10],[10,12]]
instead of [[11]] ? I guess you would need some complicated machinery
so this is one thing you have to ignore to keep your otherwise nifty
instance nice and simple.
Jared.
--
],[3,4]] * 10 = [[40,60],[40,60],[40,60],[40,60],[40,60], .
Hmm...
Jared.
Atila
Jared Updike wrote:
fromInteger x = [[fromInteger x]]
Wouldn't you want the expression
[[1,0],[0,2]] + 10
to yield
[[11,10],[10,12]]
instead of [[11]] ? I guess you would need some complicated
Instead of
fromInteger x = map repeat (repeat (fromInteger x))
I meant
fromInteger x = repeat (repeat (fromInteger x))
but it still doesn't work for multiplication.
Jared.
--
http://www.updike.org/~jared/
reverse )-:
___
Haskell-Cafe
o To output anything, I need to do 'do'.
If you only have one action, you can omit do, e.g.
main = do { putStrLn Hello, World! }
is identical (after de-sguaring) to
main = putStrLn Hello, World!
Essentially, you are correct; to output anything (i.e. to perform I/O
by side effect) your
Not to be the bad guy, but perhaps it's a good idea to remind
ourselves of our homework policy.
This?
http://www.haskell.org/hawiki/HomeworkHelp
Can I use putString ???
If you mean putStrLn and putStr, then yes. I would first make a
function that constructs the string or list of strings
Thanks, Minh. So are things like recursion and memory sharing typically out
the window?
Recursion works in C, but every function call pushes stack, so
recursive depth is limited by RAM (compare to tail call optimization
in many functional programming languages where the stack frame is
reused if
Funny. I have a module called Useful.hs with some of these same sorts
of functions. (coming from Python where I used .split(',') and
.replace('\r', '') and such a lot):
--
module Useful where
import List ( intersperse, tails )
import Numeric ( readHex )
hex2num :: (Num a) =
stumped as to how I'm going to do this. I've got about 15-20 minutes,
so I can only discuss the major features.
I was always impressed with Autrijus Tang's presentation here:
http://www.pugscode.org/euroscon/haskell.xul (view with Firefox
or other Gecko-based browser)
I think he managed
On Sun, Jun 04, 2006 at 05:17:02PM -0700, Jared Updike wrote:
stumped as to how I'm going to do this. I've got about 15-20 minutes,
so I can only discuss the major features.
I was always impressed with Autrijus Tang's presentation here:
Audrey
I think
Sorry, meant to reply all:
---
This tool (DrIFT) can derive these instances for you, if you care to
make rules for it, for Pretty:
http://repetae.net/john/computer/haskell/DrIFT/
Jared.
--
http://www.updike.org/~jared/
reverse )-:
I found this in an old post (gotta love GMail search):
You can find further information about the library at the
page http://haskell.org/haskellwiki/Library/Streams and
download it as http://freearc.narod.ru/Streams.tar.gz
from a thread in February entitled:
Streams: the extensible I/O
It would also be wise to look at occam and erlang and see if they have
any useful ideas. And, of course, Windows PowerShell.
And scsh (Scheme shell, pretty full featured these days): http://www.scsh.net/
Jared.
j.
___
Haskell-Cafe mailing list
It looks like somewhere else in your program (or a type signature
somewhere) is trying to force the result of sqrt to be an Int which
won't work since square roots are irrational (represented by the
computer as a Float or Double).
You might try (1) making sure the place where distBetween is used
I've never used that Runtime Loader package but I have gotten
hs-plugins to work:
http://www.cse.unsw.edu.au/~dons/hs-plugins/
Hope that helps,
Jared.
On 4/13/06, Tim Newsham [EMAIL PROTECTED] wrote:
Hi,
I'm about to start playing with HWS-WP (web server + plugins). It
relies on
I don't know if there's anything newer, but you could check out:
http://happs.org/HAppS/README.html
http://www.informatik.uni-freiburg.de/~thiemann/WASH/
Hope that helps,
Jared.
On 4/8/06, Tim Newsham [EMAIL PROTECTED] wrote:
Hi Everyone,
I'm new to the list, been on irc a bit. I'm
given an Ord instance (for a type T) a corresponding Eq instance can be
given by:
instance Eq T where
a == b = compare a b == EQ
where did this second -^ == come from? (I guess if if Ordering
derives Eq :-) I think you meant
instance (Ord T) = Eq T where
a == b = case compare
Thanks so much for your help. I should have made clear that I was aware that
the definitions were mutually dependent. What I was hoping was that Haskell
could solve this for me without my having to resort to effectively finessing
any sequencing considerations.
Haskell is a functional
And: has anyone already built a 'haskell-in-a-box' virtual machine?
Some are working on an all-Haskell-boots-from-scratch OS:
House (Haskell User's Operating System and Environment):
http://www.cse.ogi.edu/~hallgren/House/
From the page: House is a demo of software written in Haskell,
running
On 4/3/06, Donald Bruce Stewart [EMAIL PROTECTED] wrote:
It would also be nice to see some example sudoku solvers posted
on an `Idioms' page on haskell.org:
http://www.haskell.org/haskellwiki/Category:Idioms
someone could just create a new page 'Sudoku' and add the phrase
Chris wrote:
You need more than 5 examples. The truly evil puzzles are rarer than that.
Go
get the set of minimal puzzles and see how far your logic takes you.
Chris elucidated some of my questions before I finished writing my email...
Claus wrote:
(*) actually, that was a bit
having some trouble trying to be able to manipulate PPM images. I want to be
able to desaturate and also double the scale of them. im a first time user
of haskell so am not very familiar with it. any info would be great! thanks!
Nothing wrong with asking for help, but before you do, please
Is there a common way (standard libs, higher order) to express the
lambda part below? It's not particulary complicated but I think it is
not higher-order enough
unionBy (\x y - fst x == fst y) listOfPairs1 listOfPairs2
Something like distribute fst (==) where
distribute f op x y = f x `op` f
My understanding is that type classes in Haskell are meant to be
open, so that any code that uses your type class will work with any
new instances of that type class. This inherent open endedness causes
a problem if you are trying to enumerate all instances because at any
time someone can create a
2218 RING OPERATOR
= composite function
= APL jot
00B0 degree sign
25E6 white bullet
I don't think any other Unicode character should be considered.
That's great but
1) I have no idea how to type it. Can I easily and comfortably? In emacs?
Fortunately there are already List functions like genericLength and
genericTake, which can handle such a number type. Shouldn't be Peano
numbers part of the standard libraries?
Natural numbers are being discussed as a possible part of the new
Haskell' standard.
An additive torsor is?
Surprisingly, there is a page on MathWorld about Torsors but it is
empty. Google turned up the following page with a good explanation.
http://math.ucr.edu/home/baez/torsors.html
I'd maintain that the difference between two lengths is an entirely different
quantity from
On 3/22/06, David F. Place [EMAIL PROTECTED] wrote:
Hi All,
I really appreciate all the help I received when I asked you to
critique my PrefixMap module a few weeks ago. I think I am making
good progress in correcting the lisp in my Haskell programming.
I'll be very grateful to anyone who
(Moved to haskell-cafe)
JU General question to the list:
JU (Q) Are there any data structures in Haskell similar to C++/STL
JU vectors or C# generic Lists (i.e. strongly typed ArrayLists, e.g.
JU Listint)? These data structures grow automatically as you add
JU elements to them (but in large
General question to the list:
(Q) Are there any data structures in Haskell similar to C++/STL
vectors or C# generic Lists (i.e. strongly typed ArrayLists, e.g.
Listint)? These data structures grow automatically as you add
elements to them (but in large chunks, not one node at a time). This
data
The dates on the feed are in international (non-US) order, i.e. Mar 13
2006 = 13/03/2006. Is there a way to make this unambiguous by changing
the month to a word instead of a number? Just curious...
Jared.
On 3/16/06, Donald Bruce Stewart [EMAIL PROTECTED] wrote:
rjmh:
With a view to this
You could check out the data structures in Edison, a library of myriad
functional data structures. It may already have implemented a sequence
data structure with the desired features:
http://www.eecs.tufts.edu/~rdocki01/docs/edison/index.html
homepage:
For GHC try adding the line
import Data.Char
or
import Char
at the top of your Haskell program. Or in ghci, try Char.chr instead
of chr, etc. Or try
ghci filename.hs
where filename.hs is a text file with the line import Char at the
top. Now 'chr' should appear in scope.
The hierarchical
(Moved to haskell-cafe)
Actually, I'm trying to avoid library functions, so I can learn the
language and the functional way of thinking. How would one implement
the concatMap function?
The Haskell 98 report gives possible implementations of standard functions:
Debug.Trace, such as (trace (show foo) a)
and
System.IO.Unsafe, such as (unsafePerformIO ( print foo return a))
Or see this recent post, a trace that prints line and column numbers:
http://www.haskell.org//pipermail/haskell-cafe/2006-February/014723.html
Jared.
Dude, that was a friggin' awesome email! I'm trying to figure out how
I can just copy it wholesale into the article ;)
Use what you need. Share and share alike.
I've been struggling
with Haskell for long enough that my knowledge is now snowballing
downhill.
I think I experienced that too.
I suspect you guys are right. I had always thought of states as
being isomorphic to integers (i.e. you can be in state 0, state 1,
... state n), not as contexts (you have this input, that output, and
this token stack), am I wrong?
You're thinking of a state machine, I think, which is not
Layout only applies when something is less indented than previous
lines, I believe...
e.g.
do
c - getContents filename
putStrLn blah
or
do
x - getContents filename
putStrLn ok
works fine but
do
c - blahAction
putStrLn blah
obviously won't work
Jared.
On 3/2/06,
BH Why? Surely typing one tab is better than having to hit the
spacebar 4 (or 8)
BH times?
PC Not when it prevents me from ever exhibiting the slightest shred of style
PC in my code. I use that control for readability purposes in my code.
[snip]
BH I'm really puzled here. I've been using tabs
Well, if you are relying on exact results from floating point
arithmetic you're in trouble no matter what you do.
As long as you don't do anything irrational (exp, sin, sqrt, etc.),
you should be able to get away with using Rational. Number constants
with decimals are not automatically
(Note, moved to haskell-cafe.)
Essentially, the answer is yes, the state needs to be passed around
(neglecting hackery to simulate global variables that is better
avoided). However, this can be made convenient by using a monad.
BTW, Minh, If you don't know what monads are, then read this.
And this
public foldr:: (a - b - b) - b - [a] - b
public foldr f z [] = z
public foldr f z (x:xs) = f x (foldr f z xs)
or is it
public foldr:: (a - b - b) - b - [a] - b
foldr f z [] = z
foldr f z (x:xs) = f x (foldr f z xs)
and now things aren't lined up.
I am not sure if this has been mentioned before, but something I
would really find useful is the ability to tell Haskell to export
everything in a function except for some named functions.
No one has responded so I thought I would make a suggestion about what
the syntax might look like to do
Yep. change one line to:
entry - if isdir name /= . name /= ..
and it does in fact work.
Jared.
On 2/17/06, Jon Fairbairn [EMAIL PROTECTED] wrote:
On 2006-02-17 at 20:12GMT rgo wrote:
Hi all,
my program probably goes into infinite loop... But i cannot understand
where and why.
type introduce a type synonym, and Haskell98 forbids these in
instances, so GHC complains. GHC also lifts this restriction when
invoked with -fglasgow-exts .
http://www.haskell.org/ghc/docs/latest/html/users_guide/type-extensions.html#type-synonyms
Flexible Instances will probably be added
For scenario (a) you can use hs-plugins and ghc
http://www.cse.unsw.edu.au/~dons/hs-plugins/
With hs-plugins you can get an eval command, or you can dynamically
load Haskell modules (from source or pre-compiled .o files).
GHC (= 6.5) has an API that you can access from Haskell programs:
Or inline as
findIndices (\x - case x of Tootie _ - True; _ - False) listOfPasAndTooties
There was a recent thread about wanting a more succint way to write
this (unary pattern matching):
http://thread.gmane.org/gmane.comp.lang.haskell.cafe/11109
If John got his wish, then you could write
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