Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

FFT wrote: On Wed, May 6, 2009 at 8:20 PM, Anton van Straaten wrote: The app is written for a client under NDA, so a blog about it would have to be annoyingly vague. No doubt the potential for encountering space leaks goes up as one writes less pure code, persist more things in memory, and

Re: [Haskell-cafe] WolframAlpha

On Wed, 2009-05-06 at 17:13 -0700, Warren Henning wrote: > What I'd like to see most is WolframAlpha in action. At this point it > is vaporware to me and for all I know this could be the beginning of a > neverending charade of "coming to a Interwebs near you Real Soon Now" > every few months for t

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

FFT wrote: Anton van Straaten wrote: > The app is written for a client under NDA, so a blog about it would have to > be annoyingly vague. > No doubt the potential for encountering space leaks goes up as one writes > less pure code, persist more things in memory, and depend on more libraries. E

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

On Wed, May 6, 2009 at 8:20 PM, Anton van Straaten wrote: > The app is written for a client under NDA, so a blog about it would have to > be annoyingly vague. > No doubt the potential for encountering space leaks goes up as one writes > less pure code, persist more things in memory, and depend o

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

Jason Dagit wrote: On Wed, May 6, 2009 at 3:54 PM, Anton van Straaten wrote: FWIW, I have an internal HAppS application that's been running continuously since November last year, used daily, with stable memory usage. Do you have advice about the way you wrote you app? Things you knowingly di

Re: [Haskell-cafe] cabal parse problems

I figured out myself ... even though the parse was allegedly was on line #24 .. it was below because I used as a separator '/' instead of '.'! Kind regards, Vasili On Wed, May 6, 2009 at 7:37 PM, Vasili I. Galchin wrote: > are them some CLI switches I can enable in order to better determine wha

Re: [Haskell-cafe] cabal parse problems

are them some CLI switches I can enable in order to better determine what "parse error" is?? Kind regards, Vasili On Wed, May 6, 2009 at 6:12 PM, Vasili I. Galchin wrote: > sorrily nope, Brian ... > > Vasili > > > On Wed, May 6, 2009 at 6:06 PM, wrote: > >> On Wednesday, 06.05.09 at 18:05, Vasi

Re: [Haskell-cafe] WolframAlpha

>From what I recall of Mathematica the language, it has more in common with Lisp than Haskell: it's symbolic, dynamically typed, etc. Allegedly Wolfram spent years on this; if it has any merit, duplicating it would be difficult. What I'd like to see most is WolframAlpha in action. At this point i

[Haskell-cafe] WolframAlpha

Hello, http://blog.wolframalpha.com/2009/05/01/the-secret-behind-the-computational-engine-in-wolframalpha/ <<< this is obviously a Wolfram Inc. blog so maybe not totally objective ... but here is a snippet that speaks in Haskell's favor: As a result, the five million lines of *Mathematica* code

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

On Wed, May 6, 2009 at 3:54 PM, Anton van Straaten wrote: > FWIW, I have an internal HAppS application that's been running continuously > since November last year, used daily, with stable memory usage. Do you have advice about the way you wrote you app? Things you knowingly did to avoid space le

Re: [Haskell-cafe] cabal parse problems

Am Donnerstag 07 Mai 2009 01:05:40 schrieb Vasili I. Galchin: > Hello, > > I am trying to cabalize a package (swish .. semantic web) but am > running into parse error: > vigalc...@ubuntu:~/FTP/Haskell/Swish-0.2.1$ runhaskell Setup.hs configure > Setup.hs: swish.cabal:24: Parse of field 'expose

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

On Wed, May 6, 2009 at 4:12 PM, Jason Dagit wrote: > > While I'm thinking out loud, it would be very cool if someone wrote > some articles, say for the monad reader, that follow the formula of > the Effective C++ books. The last couple of times I've wanted a book like that, I wrote the book mys

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

On Wed, May 6, 2009 at 2:28 PM, Don Stewart wrote: > dagit: > >> In particular, we need expert Haskell programmers, such as Don, to >> write more about how they avoid space leaks in long running apps. >> Again, profiling is nice, but that's more of a tuning effort. > > I talk a bit about that in m

Re: [Haskell-cafe] cabal parse problems

sorrily nope, Brian ... Vasili On Wed, May 6, 2009 at 6:06 PM, wrote: > On Wednesday, 06.05.09 at 18:05, Vasili I. Galchin wrote: > > Exposed-modules: Swish.HaskellRDF.BuiltInDatatypes, > > ... > > Swish.HaskellRDF.GraphMatch, > > Think it probably doesn't like that tra

[Haskell-cafe] cabal parse problems

Hello, I am trying to cabalize a package (swish .. semantic web) but am running into parse error: vigalc...@ubuntu:~/FTP/Haskell/Swish-0.2.1$ runhaskell Setup.hs configure Setup.hs: swish.cabal:24: Parse of field 'exposed-modules' failed. vigalc...@ubuntu:~/FTP/Haskell/Swish-0.2.1$ Below: i

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

Jason Dagit wrote: I know from experience that lambdabot tends to be leaky. Otherwise, lambdabot wouldn't be running on my server to begin with. And, even so, Cale monitors lambdabot to make sure it is not using too many resources (and I complain when/if I notice it). I have heard similar stor

Re: [Haskell-cafe] Vector-like data structure

On Sun, 3 May 2009, Krzysztof Skrzętnicki wrote: Hi I'm looking for a data structure with following characteristics: 1. O(1) lookup 2. O(1) modification 3. amortized O(1) append 4. O(1) size query This roughly characterizes C++ vector<> class. I'm ready to implement it myself, but first I wou

Re: [Haskell-cafe] instance Monad (Except err)

Hi, Martijn van Steenbergen wrote: Mr. McBride and mr. Paterson define in their Applicative paper: data Except e a = OK a | Failed e instance Monoid e => Applicative (Except e) where ... Sometimes I'd still like to use >>= on Excepts but this "feels" wrong somehow, because it doesn't use mo

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

dagit: > In particular, we need expert Haskell programmers, such as Don, to > write more about how they avoid space leaks in long running apps. > Again, profiling is nice, but that's more of a tuning effort. I talk a bit about that in my LondonHUG talk: http://www.galois.com/blog/2009/04/27

Re: [Haskell-cafe] Current status of Annotations

I wrote a small section for the manual that will appear online (at http://www.haskell.org/ghc/docs/latest/html/users_guide/pragmas.html) when we release 6.12. I've updated the wiki page to reflect this and give some other helpful info (http://hackage.haskell.org/trac/ghc/wiki/Annotations). Cheers,

Re: [Haskell-cafe] Unfold fusion

On Wednesday 06 May 2009 4:26:15 pm Dan Doel wrote: > unfortunately it looks like I'm doing something wrong in that "coinductive > hypothesis" Sorry about the self-reply, but I realized where I went wrong. The principle of proof by coinduction for defining a function 'f' goes something like this

Re: [Haskell-cafe] setResourceLimit

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On May 6, 2009, at 16:39 , br...@lorf.org wrote: On Wednesday, 06.05.09 at 16:25, Brandon S. Allbery KF8NH wrote: No. What it means is that, if the child will continue to run in the same Haskell program after forkProcess-ing, any open Handles won't

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

Jason Dagit wrote: I don't mean to undermine your marketing efforts, but I don't think this is gossip driven. I know from experience that lambdabot tends to be leaky. Otherwise, lambdabot wouldn't be running on my server to begin with. And, even so, Cale monitors lambdabot to make sure it is n

Re: [Haskell-cafe] setResourceLimit

On Wednesday, 06.05.09 at 16:25, Brandon S. Allbery KF8NH wrote: > No. What it means is that, if the child will continue to run in the > same Haskell program after forkProcess-ing, any open Handles won't > work right. You could fix this with handleToFd and fdToHandle, I > suspect, but it's irrele

Re: [Haskell-cafe] Unfold fusion

On Wednesday 06 May 2009 11:27:08 am Adrian Neumann wrote: > Hello, > > I'm trying to prove the unfold fusion law, as given in the chapter > "Origami Programming" in "The Fun of Programming". unfold is defined > like this: > > unfold p f g b = if p b then [] else (f b):unfold p f g (g b) > > And th

Re: [Haskell-cafe] setResourceLimit

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On May 6, 2009, at 16:18 , br...@lorf.org wrote: On Tuesday, 05.05.09 at 22:48, Brandon S. Allbery KF8NH wrote: On May 5, 2009, at 04:52 , br...@lorf.org wrote: I have a long-lived multithreaded server process that needs to execute programs and i

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

On Wed, May 6, 2009 at 1:01 PM, Don Stewart wrote: > fft1976: >> I've heard it's hard to contain a long-running Haskell application in >> a finite amount of memory, but this is probably not a problem if your > > Hmm. Gossip driven development? I don't mean to undermine your marketing efforts, but

Re: [Haskell-cafe] setResourceLimit

On Tuesday, 05.05.09 at 22:48, Brandon S. Allbery KF8NH wrote: > On May 5, 2009, at 04:52 , br...@lorf.org wrote: >> I have a long-lived multithreaded server process that needs to execute >> programs and interact with them via Handles. The programs could >> misbehave, like loop or hang, so I need t

Re[2]: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

Hello FFT, Wednesday, May 6, 2009, 11:59:53 PM, you wrote: > I've heard it's hard to contain a long-running Haskell application in > a finite amount of memory not exactly. you may alloc fixed pool of memory to application (say, 1gb) if you know that it never need more memory. but as far as you d

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

fft1976: > I've heard it's hard to contain a long-running Haskell application in > a finite amount of memory, but this is probably not a problem if your Hmm. Gossip driven development? > web site sleeps 0.001% of the time (like XMonad), or you can restart > it every once in a while without anyone

Re: [Haskell-cafe] Is Haskell a Good Choice for Web Applications? (ANN: Vocabulink)

I've heard it's hard to contain a long-running Haskell application in a finite amount of memory, but this is probably not a problem if your web site sleeps 0.001% of the time (like XMonad), or you can restart it every once in a while without anyone noticing.

Re: [Haskell-cafe] beginner question: assigning local variable to a function

Brandon S. Allbery KF8NH wrote: On May 6, 2009, at 12:18 , Nico Rolle wrote: why does this don't work? test = let a = (>) in 1 `a` 2 Works fine here once I correct your indentation (the "in" needs to be indented at least as far as the "l" in "let"). Really? For me it's enough to have

Re: [Haskell-cafe] Reply to

Miguel Mitrofanov wrote: Anyway, I can't see why we still use mailing lists when we have reddit, which has all the good parts of mailing lists (nested messages), while it also: Hmm, what's this reddit thing? *googles* Me too. Seems like this "reddit" thing is nothing but a mail list done wro

Re: [Haskell-cafe] Reply to

Am Mittwoch 06 Mai 2009 16:57:16 schrieb David Miani: > On Wednesday 06 May 2009 20:42:38 Daniel Fischer wrote: > > Indeed. I have reply, reply-to-all and reply-to-list one click or one key > > combination away, and as far as I know those features are present in > > almost all mail clients since se

Re: [Haskell-cafe] Reply to

Anyway, I can't see why we still use mailing lists when we have reddit, which has all the good parts of mailing lists (nested messages), while it also: Hmm, what's this reddit thing? *googles* Me too. Seems like this "reddit" thing is nothing but a mail list done wrong. I may be wrong, but

Re: [Haskell-cafe] Reply to

On Thursday 07 May 2009 01:28:36 Matthijs Kooijman wrote: > Hi David, > > > - Do you use To for the mailing list or for the parent? > > - Do you ever include the grand-parent in the recipient list? > > I use whatever my mail client does when I hit "list-reply" :-) > > For me (using mutt), that mean

Re: [Haskell-cafe] Haskell IO problem

On Wed, May 6, 2009 at 4:27 PM, applebiz89 wrote: > > main :: IO() > do putStr "Hi there! what is your name: " > fanName = getLine > do putStr "1 = Insert film, 2 = Become a Fan, 3 = The number of fans of a > film, 4 = Film released in a year: " > input = getLine > read input :: Int > (if input ==

Re: [Haskell-cafe] Getting WriterT log lazily

Magnus Therning wrote: > Martijn van Steenbergen wrote: >> >> Otherwise, you can use unsafeInterleaveIO: no unsafePerformIO or seq >> needed, but there's still "unsafe" in that name there. This works for me: ... > Thanks, that does indeed work, but it still requires that "unsafe" there so > I'm hes

Re: [Haskell-cafe] beginner question: assigning local variable to a function

Oh sorry guys was rlly a stupid indentation mistake next time i'll post the error message too thanks regards 2009/5/6 Brandon S. Allbery KF8NH : > On May 6, 2009, at 12:18 , Nico Rolle wrote: >> >> why does this don't work? >> >> test = let a = (>) >>   in 1 `a` 2 > > > Works fine here once I corr

Re: [Haskell-cafe] beginner question: assigning local variable to a function

On May 6, 2009, at 12:18 , Nico Rolle wrote: why does this don't work? test = let a = (>) in 1 `a` 2 Works fine here once I correct your indentation (the "in" needs to be indented at least as far as the "l" in "let"). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf

[Haskell-cafe] beginner question: assigning local variable to a function

hi why does this don't work? test = let a = (>) in 1 `a` 2 regards ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Unfold fusion

On 6 May 2009, at 19:27, Adrian Neumann wrote: Hello, I'm trying to prove the unfold fusion law, as given in the chapter "Origami Programming" in "The Fun of Programming". unfold is defined like this: unfold p f g b = if p b then [] else (f b):unfold p f g (g b) And the law states: unf

Re: [Haskell-cafe] Unfold fusion

Adrian Neumann schrieb: Hello, I'm trying to prove the unfold fusion law, as given in the chapter "Origami Programming" in "The Fun of Programming". unfold is defined like this: unfold p f g b = if p b then [] else (f b):unfold p f g (g b) And the law states: unfold p f g . h = unfold p'

Re: [Haskell-cafe] calling a variable length parameter lambda expression

Keep in mind that using lists for your parameters means you lose static guarantees that you've passed the correct number of arguments to a function (so you could crash at runtime if you pass too few or too many parameters to a function). On Wed, May 6, 2009 at 11:41 AM, Nico Rolle wrote: > super

Re: [Haskell-cafe] calling a variable length parameter lambda expression

super nice. best solution for me so far. big thanks. regards 2009/5/6 Victor Nazarov : > On Tue, May 5, 2009 at 8:49 PM, Nico Rolle wrote: >> >> Hi everyone. >> >> I have a problem. >> A function is recieving a lambda expression like this: >> (\ x y -> x > y) >> or like this >> (\ x y z a -> (x >

Re: [Haskell-cafe] calling a variable length parameter lambda expression

isn't doLam just id with an Ord restriction there? On Wed, May 6, 2009 at 5:55 AM, Victor Nazarov wrote: > On Tue, May 5, 2009 at 8:49 PM, Nico Rolle wrote: >> >> Hi everyone. >> >> I have a problem. >> A function is recieving a lambda expression like this: >> (\ x y -> x > y) >> or like this >>

Re: [Haskell-cafe] Reply to

Hi David, > - Do you use To for the mailing list or for the parent? > - Do you ever include the grand-parent in the recipient list? I use whatever my mail client does when I hit "list-reply" :-) For me (using mutt), that means to include any recipients and senders from the original message (so

[Haskell-cafe] Unfold fusion

Hello, I'm trying to prove the unfold fusion law, as given in the chapter "Origami Programming" in "The Fun of Programming". unfold is defined like this: unfold p f g b = if p b then [] else (f b):unfold p f g (g b) And the law states: unfold p f g . h = unfold p' f' g' with p' =

Re: [Haskell-cafe] Haskell Arrows Applications

On 07:33 Wed 06 May , Hannousse wrote: > > Hello, > > I'm interested to the concept of arrows in Haskell, however, I couldn't find > a real application or example using this new technology in a real world > application. All what I found are just academic examples and other people > developing

RE: [Haskell-cafe] Current status of Annotations

Annotations are indeed implemented and in the HEAD. Looking at [1], the writeup looks historically skewed, rather than being a crisp writeup of what is actually there. I wonder if Max or Tristan might improve the situation (after the Haskell workshop deadline)? As it happens Tristan's Haskell

Re: [Haskell-cafe] Reply to

On Wednesday 06 May 2009 20:42:38 Daniel Fischer wrote: > > Indeed. I have reply, reply-to-all and reply-to-list one click or one key > combination away, and as far as I know those features are present in almost > all mail clients since several years, so ease of replying to list shouldn't > be an i

[Haskell-cafe] Current status of Annotations

Hello, I've been reading about Annotations [1] as implemented during last years Summer of Code, and about some earlier ideas [3] [2]. It seems though that these annotations have never been merged into HEAD [4]. Could anyone elaborate on the current status of this proposal? Has there been any furt

Re: [Haskell-cafe] Writing a compiler in Hakell

Dear Rouan, on http://www.cs.uu.nl/wiki/HUT/WebHome you will find a collection of tools which may help you to construct a compiler. As an example you will find a Tiger compiler constructed with the uulib tools and the uuagc attribute grammar system. Tiger is the language used in the book

[Haskell-cafe] Haskell Arrows Applications

Hello, I'm interested to the concept of arrows in Haskell, however, I couldn't find a real application or example using this new technology in a real world application. All what I found are just academic examples and other people developing new specific libraries using arrows.Could someone, pleas

[Haskell-cafe] Re: Writing a compiler in Hakell

On 06/05/2009 07:31, Luke Palmer wrote: On Wed, May 6, 2009 at 12:07 AM, Rouan van Dalen mailto:rvda...@yahoo.co.uk>> wrote: Hi everyone. I am designing my own programming language. I would like to know what is the best way to go about writing my compiler in haskell. What

[Haskell-cafe] Re: ST.Lazy vs ST.Strict

On 05/05/2009 20:42, Tobias Olausson wrote: This simple implementation of CPU does not behave as expected in the latest version of ghc using ST.Lazy since it updates the `pc` in the wrong order. When we use ghc-6.8 the code works as expected both with lazy and strict ST. How is that? How do we f

Re: [Haskell-cafe] Writing a compiler in Hakell (continued 1)

On Wed, May 6, 2009 at 4:17 AM, Rouan van Dalen wrote: > > As for the target language, im not quite sure yet. I am doing a lot of > work in > .NET/C# at the moment, but I would eventually like to use my own > programming language, > instead of C#. I would also like to use my language for linux

[Haskell-cafe] Haskell IO problem

I havent done much IO at all in haskell, only within the function itself. However I want to get the input from the interface for the function and havent done this before. // Say I have this as my data type and list of films data Film = Film String String Int [String] -- List of films testDatabas

Re: [Haskell-cafe] Reply to

Am Mittwoch 06 Mai 2009 11:05:05 schrieb Magnus Therning: > On Wed, May 6, 2009 at 7:51 AM, Ashok Gautham > > wrote: > > I feel that the haskell mailing lists must have the reply-to field set, > > so that a person can reply to the list by just clicking reply. > > > > I am unsure if I am the only o

[Haskell-cafe] Writing a compiler in Hakell (continued 1)

Hi everyone. Thanks for the speedy replies. Let me elaborate on my language and situation. The language I have in mind is a statically typed, hybrid (OOP + functional), strict language. It contains both functional and imperitive features (much the same as OCaml/F#) with ideas from haskell, sch

Re: [Haskell-cafe] calling a variable length parameter lambda expression

On Tue, May 5, 2009 at 8:49 PM, Nico Rolle wrote: > Hi everyone. > > I have a problem. > A function is recieving a lambda expression like this: > (\ x y -> x > y) > or like this > (\ x y z a -> (x > y) && (z < a) > > my problem is now i know i have a list filled with the parameters for > the lamb

Re: [Haskell-cafe] Reply to

On Wed, May 6, 2009 at 7:51 AM, Ashok Gautham wrote: > I feel that the haskell mailing lists must have the reply-to field set, so > that > a person can reply to the list by just clicking reply. > > I am unsure if I am the only one facing this problem. This is a contentious issue: http://www.uni

Re: [Haskell-cafe] Writing a compiler in Hakell

On May 6, 2009, at 8:07 AM, Rouan van Dalen wrote: Hi everyone. I am designing my own programming language. I would like to know what is the best way to go about writing my compiler in haskell. What are the tools available in haskell that can help with compiler construction? I know about

Re: [Haskell-cafe] Writing a compiler in Hakell

2009/5/6 Rouan van Dalen > > I know about Happy.  Is that a good tool to use? Alex and Happy are used in (at least) these two packages:    http://hackage.haskell.org/cgi-bin/hackage-scripts/package/language-python    http://hackage.haskell.org/cgi-bin/hackage-scripts/package/language-c You shou

Re: [Haskell-cafe] Reply to

Hi Ashok, > I feel that the haskell mailing lists must have the reply-to field set, so > that > a person can reply to the list by just clicking reply. Most email clients have a "followup" or "reply-to-all" feature, that will do this. Better email clients also support (setting and reading) the Mai

Re: [Haskell-cafe] List comprehension

por...@porg.es wrote: -- or with Data.Function.Predicate (shameless plug) : Whoa, a function called "isn't", why is this the first time I see that? :-) Martijn. _

Re: [Haskell-cafe] Writing a compiler in Hakell

Rouan van Dalen wrote: Hi everyone. I am designing my own programming language. I would like to know what is the best way to go about writing my compiler in haskell. What are the tools available in haskell that can help with compiler construction? I know about Happy. Is that a good tool to