Hi all,
I've been going over my code trying to get it all to compile with
"ghc -Wall -Werror", without introducing constructs that would make
my code the laughing stock of the dynamic typing community. They
already think we're nuts; my daydreams are of a more computer
literate society whe
On Jun 22, 2007, at 11:42 AM, David Roundy wrote:
On Fri, Jun 22, 2007 at 11:37:15AM -0700, Dave Bayer wrote:
GHC issues a "Warning: Defaulting the following constraint(s) to type
`Int'" for the definition of z.
Why don't you just use -fno-warn-type-defaults?
...
ghc -W
I couldn't find a compile-time here document facility, so I wrote one
using Template Haskell:
module HereDocs(hereDocs) where
import Control.Exception
import Language.Haskell.TH.Syntax
getDoc :: String -> [String] -> (String,[String])
getDoc eof txt =
let (doc,rest) = break (== eof) txt
On Jun 22, 2007, at 2:46 PM, David Roundy wrote:
I think of top-level type declarations as type-checked comments,
rather
than a seat-belt. It forces you to communicate to others what a
function
does, if that function may be used elsewhere. I like this.
Although it can
be cumbersome for q
On Jun 22, 2007, at 12:34 PM, Dave Bayer wrote:
In particular, I always want defaulting errors, because sometimes I
miss the fact that numbers I can count on my fingers are defaulting
to Integer.
So no one took the bait to actually offer me a shorter idiom, but I
thought about the above
On Jun 22, 2007, at 4:37 PM, David Roundy wrote:
You get strongly-typed code whether or not you enable warnings.
In my opinion it's delusional to think one is using strong typing if
one doesn't enable warnings. All the puffing about the advantages of
strong typing look pretty silly if code
On Jun 22, 2007, at 3:11 PM, Brandon S. Allbery KF8NH wrote:
(1) any way to flag a pattern match as "I know this is okay", don't
warn about it" without shutting off pattern match warnings completely?
GHC doesn't issue warnings about patterns on the left of =
For example, the following code c
On Jun 25, 2007, at 4:48 AM, Simon Peyton-Jones wrote:
The intention is that it should be straightforward to suppress
warnings.
Simply add a type signature for 'z', or for the naked 3 in z's
definition.
I constructed my example from larger modules peppered with small
integer constants;
On Jun 25, 2007, at 8:15 AM, Simon Peyton-Jones wrote:
i2 = 2 :: Int
i3 = 3 :: Int
The code
{-# OPTIONS_GHC -Wall -Werror #-}
module Main where
i2 = 2 :: Int
i3 = 3 :: Int
main :: IO ()
main = putStrLn $ show (i2,i3)
generates the errors
Main.hs:5:0: Warning: Definition but no type si
On Mon, Jun 25, 2007 at 07:31:09PM +0100, Ian Lynagh wrote:
I don't know if (^) in particular is what is causing you problems, but
IMO it has the wrong type; just as we have
(!!) :: [a] -> Int -> a
genericIndex :: (Integral b) => [a] -> b -> a
we should also ha
On Jun 28, 2007, at 12:17 PM, Greg Meredith wrote:
Haskellians,
Once you have a polymorphic let, why do you need 'let' in the base
language, at all? Is it possible to formulate Haskell entirely with
do-notation where there is a standard monad for let environments?
Probably this was all di
On Jun 28, 2007, at 9:49 PM, Stefan Holdermans wrote:
That way you would have to use monads everywhere.
As you already hinted at in a later message, this has to do with
let-bindings being potentially polymorphic and monadic bindings
being necessarily monomorphic:
Are there papers that p
On Jun 29, 2007, at 10:07 AM, Nicolas Frisby wrote:
I wrote a combination reader/writer monad (a la the RWS monad in the
mtl) and I find myself wanting to use multiple instances of it in the
same stack of transformers. The functional dependencies prevent this
from working out.
I found myself i
On Jun 30, 2007, at 6:31 AM, Claus Reinke wrote:
has anyone else had similar experiences with expressive limitations
of monadic programming? things that one might be able to work
around, but that don't feel as natural or simple as they should be?
things that one hasn't been able to express at all
On Jul 5, 2007, at 8:00 AM, Paul Moore wrote:
It probably depends on your perspective. I've found lots of tasks that
would be a simple library call in Python, but which require me to
write the code myself in Haskell. Examples:
* Calculate the MD5 checksum of a file
How's this, only one line
On Jul 5, 2007, at 9:52 AM, Paul Moore wrote:
You're changing the problem from finding a Haskell library (which only
needs to be installed on the development machine at compile time) to
finding a 3rd party utility, which has to be installed at runtime
...
Not a good trade-off.
The intersecti
On Jul 7, 2007, at 4:23 AM, Thomas Conway wrote:
the performance model for haskell programs is at best inscrutable
I punched my first Basic program by hand with a paper clip, in my
high school library. Even after experiencing an APL interpreter at
19, it has taken half my life to fully int
Learning Haskell, the Prelude.ShowS type stood out as odd, exploiting
the implementation of lazy evaluation to avoid explicitly writing an
efficient concatenable list data structure. This felt like cheating,
or at least like using a screwdriver as a crowbar, to be less
judgmental.
Recentl
On Jul 9, 2007, at 6:52 PM, Donald Bruce Stewart wrote:
bayer:
Learning Haskell, the Prelude.ShowS type stood out as odd, exploiting
the implementation of lazy evaluation to avoid explicitly writing an
efficient concatenable list data structure.
See also
http://hackage.haskell.org/cgi-b
peterv telenet.be> writes:
> I tried to do something in CAL that I could not solve without
> functional dependencies. In their support forum, it got mentioned
> that func.deps propably won't make into the next Haskell standard...
> Any comments on that?
Here's a link "CAL for Haskell Programmers
Claus Reinke talk21.com> writes:
> will ultimately make its contents easier to find. but if you
> want to avoid answering questions again and again on the
> list, you need to improve the cache of answers.
Bingo. On less technical forums, e.g. FlyerTalk, the "do a search" equivalent to
"RTFM" is
Malcolm Wallace cs.york.ac.uk> writes:
> Yes, the sheer volume of posts is definitely becoming a problem (for me,
> at least).
As a newcomer I was stunned that this otherwise very sophisticated community was
using an email list rather than a bulletin board. The shear torrent of email was
impactin
Gregory Propf yahoo.com> writes:
> So what the hell is the difference between them? Int and Integer.
> They aren't synonyms clearly. What's going on?
http://www.haskell.org/haskellwiki/Learn_Haskell_in_10_minutes
is a good starting point for answering this and similar questions.
___
Creighton Hogg gmail.com> writes:
> Hi Haskell, Sorry to contribute to the noise but given that we've been
> talking about categories lately, I was wondering if anyone had any
> opinions on good universities for studying category theory. I'm
> trying to figure out where to apply for my phd. I
I am one of the authors of
Dave Bayer, Persi Diaconis
Trailing the dovetail shuffle to its lair
Ann. Appl. Probab. 2 (1992), no. 2, 294-313
which found a closed form formula for the probabilities involved in riffle
shuffles, how people shuffle e.g. playing bridge. This work was summarized as
apfelmus quantentunnel.de> writes:
> While your observation that merge may create an implicit heap is true,
> it doesn't happen in your code :) When unfolding the foldr1, we get
> something like
>
> 2:.. `merge'` (3:.. `merge'` (5:.. `merge1` (...)))
>
> i.e. just a linear chain of merges. Re
Miguel Mitrofanov yandex.ru> writes:
> There are a lot of tutorials ensuring the reader that, although
> Haskell is based on category theory, you don't have to know CT to use
> Haskell. So, is there ANY Haskell tutorial for those who do know CT?
If you know category theory, it's a good bet that
Ronald Guida mindspring.com> writes:
> I started looking at the Euler problems [1]. I had no trouble with
> problems 1 through 10, but I'm stuck on problem 11. I am aware that
> the solutions are available ([2]), but I would rather not look just
> yet.
I am the author of that solution
Here is another prime sieve. It is about half the length of the
fastest contributed code (ONeillPrimes) and nearly as fast until it
blows up on garbage collection:
% cat ONeillPrimes.hs | grep -v "^--" | wc
18511056306
% cat BayerPrimes.hs | grep -v "^--" | wc
85 566
As an exercise, trying to understand the beautiful paper
Stream Fusion
From Lists to Streams to Nothing at All
Duncan Coutts, Roman Leshchinskiy and Don Stewart
http://www.cse.unsw.edu.au/~dons/papers/CLS07.html
http://www.cse.unsw.edu.au/~dons/streams.html
Simon Michael joyful.com> writes:
>
> Hi Andreas - very good problem report, thanks.
>
> I have just cleaned up the archive links at
> http://www.haskell.org/haskellwiki/Mailing_lists a bit. I added the
> ever-excellent gmane and an overview of all archives.
Ok, this list was crushing my OS
It appears that at least on gmane, my posts to this thread ended up as
singletons, breaking the thread. Here are the posts:
http://article.gmane.org/gmane.comp.lang.haskell.cafe/26426
http://article.gmane.org/gmane.comp.lang.haskell.cafe/26466
___
Hask
Donald Bruce Stewart cse.unsw.edu.au> writes:
> bayer:
> > I couldn't find a compile-time here document facility, so I wrote one
> > using Template Haskell:
>
> Very nice! You should wrap it in a little .cabal file, and upload it to
> hackage.haskell.org, so we don't forget about it.
>
> Deta
Ok, I'm writing a command line tool, using System.Console.GetOpt to
handle command line arguments. My Flags structure so far is
data Flag
= Filter String
| DateFormat String
| DocStart String
| DocEnd String
...
and I want to write accessor functions that return the strings i
Neil Mitchell gmail.com> writes:
> then lookup, instead of just "" as the else clause.
Thanks, all. After digesting what was on this thread as I woke up this
morning, I ended up writing something rather close to this.
I have a reusable wrapper around System.Console.GetOpt that adds
> type Opt
peterv telenet.be> writes:
> Does Haskell support any form of automatic memorization?
I used a C compiler in the 1980's that would routinely put values into
registers that were already there, so I'm deeply suspicious in ways that
turn out to always be completely unwarranted for GHC. Nevertheless
Chris Smith twu.net> writes:
> Can someone clarify what's going on with the standard library in
> Haskell?
...
> sites for the thousandth time before realizing that so-and-so's GUI
> library hasn't actually been touched since they finished their class
Short answer: Our system is very democrat
If one is calling runInteractiveCommand for a "sure-thing" returning a small
amount of output (say, "ls" for a modest directory"), is it necessary to call
waitForProcess?
My waitForProcess calls came under scrutiny when I tried to GHC profile a
threaded process, which isn't possible. It turns out
Bryan O'Sullivan serpentine.com> writes:
> Pardon me while I veer off-topic, but you could also use Pandoc to do
> this. No forking required.
> http://sophos.berkeley.edu/macfarlane/pandoc/
What I'm doing is neither Haskell nor Markdown specific; I allow any HTML
markup filter that plays nice
So I stared at the documentation in Control-Concurrent, learned about
finally and MVar variables, and crossed the genes from the suggestions here
to come up with
runCommand :: String -> String -> IO (String,Bool)
runCommand cmd input = do
(inp,out,err,pid) <- runInteractiveComman
I recently did the classic "push a shopping cart down the aisle at
Fry's" to build a Core 2 Quad computer, with Linux swap and a soft
raid array spread across three 750 GB sata hard disks. I had some
potential "first build" issues, notably a mishap with the lawn of
copper grass that passes for a 7
What is the best way to embed an arbitrary file in a Haskell program?
I would like to use GHC to compile command-line tools to be used with
OS X. I want the tool to be a single file, not a package or a
directory, that makes no assumptions about what else is present. For
example, it should b
On Feb 7, 2008, at 12:27 AM, [EMAIL PROTECTED] wrote:
Are you assuming that the various users have GHC/Hugs installed? You
know about scripting through the 'runhaskell' binary, right?
I do, and I've used this. I don't want to do that here.
Let me say this again: I am making no assumptions w
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