[Haskell] Reminder: The Chalmers Online Functional Programming Seminar Series (THIS WEEK: Nadia Polikarpova)

The *Chalmers Online Functional Programming Seminar Series * is organized by the Chalmers Functional Programming Group, as a way to exploit the fact that so many of us in the FP community are already meeting and working online these days. Our aim is to bring the people in

[Haskell] Announcement: The Chalmers Online Functional Programming Seminar Series (TODAY: Benjamin Pierce!)

The *Chalmers Online Functional Programming Seminar Series * is organized by the Chalmers Functional Programming Group, as a way to exploit the fact that so many of us in the FP community are already meeting and working online these days. Our aim is to bring the people in

[Haskell] Chalmers is advertising positions, deadline April 6

Dear all, Chalmers University of Technology has 2-3 open positions in the division of Software Technology (which consists of functional programming, language based security and formal methods). Please consider applying! And/or forward to people you know who would be interested. Application

[Haskell] 2 PhD student and 2 Post-doc positions at Gothenburg University, in Language Technology / Formal Methods

environment with about 70 faculty and 70 PhD students from about 30 countries. The PhD positions are located jointly in two research groups: Language Technology and Formal Methods. The PhD supervisors will be professors from these groups: Aarne Ranta (REMU principal scientist), Koen Claessen, and Gerardo

[Haskell] PhD Positions in Functional Programming at Chalmers University of Technology

Chalmers is hiring PhD students in the Functional Programming group, to work on topics such as domain-specific languages, compilers, testing, automated reasoning, computer linguistics, and more. Read the announcement here:

[Haskell] PAR 2010: First CFP

(I am sending this on behalf of a colleague) [Papers dealing with partiality and termination using monadic programming or other functional programming techniques are welcome] Please distribute to those you might think are interested.

[Haskell] Two Positions as Associate Professor in Software Engineering at Chalmers University

://www.chalmers.se/cse/EN/news/vacancies/positions/two-positions-as The application deadline is January 12, 2009. Happy New Year! -- Koen Claessen ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell

[Haskell] Call for papers TAP 2009

[Apologize if you receive multiple copies] Call for Papers TAP: Tests And Proofs 2009 The Third International Conference on Tests And Proofs (TAP) will be held at ETH Zurich, Switzerland on 2 and 3 July 2009. It will be co-located with TOOLS Europe 2009. The TAP

Re: [Haskell] Abusing quickcheck to check existential properties

Hi Norman, But how do I use QuickCheck to check an existential? The standard method in QuickCheck is to be constructive, and actually implement the function that constructs for the value. So, instead of forAll x . exists y . P(x,y) you write forAll x . P(x, find_y(x)) for a suitably

[Haskell] PhD positions in Functional Programming at Chalmers in Sweden

) theorem proving techniques, and integration of these different techniques. There is a possibility of attacking real-world problems from our industrial partners. For more information, please look at: http://www.cs.chalmers.se/~koen/phdad.html Koen Claessen John Hughes

Re: [Haskell] ANNOUNCE: ParseP library 0.1

Hi Twan, You might be interested in a different implementation of the ReadP stuff, namely my Parsek combinator library, which I made some years ago. It tries to mimic Daan Leijen's Parsec library closely, but instead uses the ideas behind the ReadP library.

[Haskell] Fwd: HFL07, student stipend(s) available

Workshop on Hardware design and Functional Languages HFL'07, Braga, Portugal, March 24 and 25 (with the ETAPS conferences) Student stipend(s) available, deadline March 13 HFL07 is pleased to announce the availability of one or two stipends for students to attend the workshop. We will give

[Haskell] New PhD Positions Computing Science, Chalmers University

and verification. For more information on this point contact Mary Sheeran (ms(at)cs.chalmers.se); - automated theorem proving, SAT-solving, and functional programming. For more information on this point see http://www.cs.chalmers.se/~koen/folkung/, or contact Koen Claessen (koen(at)chalmers.se

[Haskell] Re: QuickCheck revival and Cabal

There is currently an old QuickCheck version in the standard hierarchy in Test.QuickCheck. As the new QuickCheck is incompatible with the old one, I do not want to override that place. Rather, I would like to create my own little space in the hierarchy where the new version can sit and develop.

[Haskell] QuickCheck revival and Cabal

Dear all, For the past couple of years, I have been quietly hacking on a brand new version of QuickCheck with lots of cool features. I have been distributing copies to some friends, but have not released any official package. Now, after lots of peer pressure, the time has come that I want to

Readline on Windows?

Hi, Compiling the following program (Bug.hs): module Main where import System.Console.Readline main = do ms - readline Hi print ms Using GHC 6.2.2 on Windows XP, using the command line: ghc --make Bug -o bug Produces the following message: Chasing modules from: Bug Compiling

Derivable type classes bug?

Hi, Take a look at the following program, making use of derivable type classes. module Bug where import Data.Generics class Foo a where foo :: a - Int foo{| Unit |}_ = 1 foo{| a :*: b |} _ = 2 foo{| a :+: b |} _ = 3 instance Foo [a] GHC 6.2.2 produces the following error

Re: [Haskell] Re: Global Variables and IO initializers

Benjamin Franksen wrote: | I think hiding the fact that certain objects are not | constants but functions is a bad idea, because it will break | sharing in a lazy implementation. | | You probably mean the case where the implicit parameter | is the only one. I don't see why that would

[Haskell] Re: Global Variables and IO initializers

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 full IO actions as initialization actions might be a bit too

[Haskell] [QCQ] Haskell-QuickCheck Questionnaire

Dear Haskell-QuickCheck user, When John and I published the first paper about QuickCheck in 2000, we released a Haskell module that was cleary marked as DRAFT. Since then, a lot of things have happened; we and other people have made extensions and improvements to QuickCheck, but only very few of

[Haskell] Workshop: CUFP

. There will be no published proceedings. The meeting is intended to be more of a discussion forum than a technical interchange. Committee Koen Claessen Byron Cook David Fox John Lalonde John Launchbury (Chair) ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org

Re: [Haskell] Re: overuse of maybe and [] in prelude and libs, PS

foldr (++) [] [[i] | i - [1..n]] behaves linearly in n. /Koen -- Koen Claessenhttp://www.cs.chalmers.se/~koen/ Chalmers University of Technology, Gothenburg, Sweden ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman

Re: [Haskell] Re: Data.Set whishes

-- Koen Claessenhttp://www.cs.chalmers.se/~koen/ Chalmers University of Technology, Gothenburg, Sweden ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell

Re: [Haskell] Re: Data.Set whishes

| One could possibly argue that the right solution is to | put the operations in classes? The problem is that sometimes the type of an operation on a particular data structure is not completely according to the general structure. There might be extra restrictions on the type arguments for

Re: Why are strings linked lists?

Wolfgang Jeltsch wrote: | 1. Today I spend a few hours trying to track down a memory leak. It | turns out I just didn't realize how much space a string takes up. | On my machine replicate 500 'a' will use 90MB of space! | | You have to take into account that Chars (in GHC)

RE: interact behaves oddly if used interactively

Simon Marlow wrote: | For example, eager evaluation would be a completely | valid implementation strategy for Haskell if it were | not for lazy I/O. I do not understand this remark. As far as I know, in any valid implementation of Haskell, the following expression: const 3 undefined

Re: The Future of Haskell discussion at the Haskell Workshop

Karl-Filip Faxen wrote: | Yes, things are clearer and I rather like the idea. | The only thorny issue is that the update function for | field 'wibble' is formed from but not equal to the | field name itself. This could be solved by having an abstract type Field thusly (*): type Field r a

RE: Ann: HAllInOne bug fix release

Simon Peyton-Jones wrote: | I don't know why the all in one version might go | slower though. How about some (artificial) cut-offs during optimization phases? Optimizing a hugs module could lead to some kind of combinatorial explosion (which gets cut off by the optimizer) which does not happen

Re: yet another very simple overlapping instance example

| instance (Num a) = Op_plus a MyInt where | i `plus` (MyInt b) = i + b Remember that b is of type Int, but you also say that i is of any Num type. This clashes, since + requires both if its arguments to hve the same types. /K ___ Haskell

Re: Dynamic Compilation

| Ghci and Template Haskell show that it is possible to | compile and load a module into a running program. Is | there a user interface to do that? Would one be | possible? Would that make a Haskell analog of Yaws | (yaws.hyber.org) possible? | | For those who don't know Yaws: It is a

Re: Typesafe MRef with a regular monad

possible to do (unless you think any monad by itself is an imperative thing). The only thing one needs to focus on is the typing and not the imperativeness. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden

Re: Typesafe MRef with a regular monad

Someone asked me: | I don't recall the message you are referring to, and I | can't find it in the archive. Can you point me at it? Sorry, I meant: http://www.haskell.org/pipermail/haskell/2001-September/007922.html /K :-) ___ Haskell mailing list

Re: linking ghc object files with mingw-g++

| I'm trying to link ghc object files with mingw's | g++/ld... We have used the g++-2 compiler that you can get with Cygwin and it seems to work fine. (mingw-g++ and the normal g++ did not work for us.) Another hint: maybe you should give -lstdc++ as a flag to the final linking fase. A final

Re: data vs. newtype, abstractly

Hal Daume III wrote: | there is a difference between | | (N undefined) `seq` () | | and | | (D undefined) `seq` () The question stated without its constructor. My guess is no. /K ___ Haskell mailing list [EMAIL PROTECTED]

Re: silly questions about 'seq'

is a simple example: funs :: [Int - Int] funs = [ \x - x + i | i - [1..] ] f :: Int - Int f = funs !! 100 Calculating f, without applying it to arguments, really takes some time. Hope this helps, /Koen -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg

Re: FFI C++ Cygwin

paths which the mingwin g++ did not understand but that was easily fixed by replacing mingwin's g++ by a script that first converts all its arguments which look like filenames to windows-paths and then calls mingwin's g++. Anyway, thanks for everyone's suggestions! /Koen. -- Koen Claessen http

FFI C++ Cygwin

Dear GHC users, I have the following problem and I wonder if anyone can help. I am using the FFI to talk to a library of functions written in C++. On Unixes (Solaris, Linux) this works just fine if one adds the right -ldstdc++ here and there. However, I am using Cygwin now and that is where

RE: 5.04.2 schedule?

Simon Marlow wrote: | [...] and in any case binary packages always pop out | of the end of the nightly build, so building them | isn't any extra hassle. : | So I think the current situation is a good compromise: | those who want the bleeding edge can get CVS and watch | [EMAIL PROTECTED]

Pure File Reading (was: Dealing with configuration data)

, there are no space problems.) There could of course be pure -Once versions of other IO operations. Here is a list of possibilities: - reading a file - getting arguments - getting environment variables - downloading a webpage - ... What do you think? Regards, /Koen. -- Koen Claessen http

Re: Dealing with configuration data

) that the contents of a file would not change during the evaluation of a Gofer program. Regards, /Koen. (*) Actually, a Haskell compiler is free to inline these kind of expressions, so really one has to give a NOINLINE pragma to the compiler as well. -- Koen Claessen http://www.cs.chalmers.se/~koen

Pure File Reading (was: Dealing with configuration data)

, there are no space problems.) There could of course be pure -Once versions of other IO operations. Here is a list of possibilities: - reading a file - getting arguments - getting environment variables - downloading a webpage - ... What do you think? Regards, /Koen. -- Koen Claessen http

Re: Dealing with configuration data

Nick Name wrote: | The first idea from Koen Claessen (getConfig operates | directly on the file with unsafePerformIO) appears to | work, but this time we are *relying* on the fact that | the function will be evaluated once, since the file | could change and multiple evaluations

RE: unsafePerformIO

Simon Peyton-Jones wrote: | The actions performed by unsafePerformIO are simply | done at some entirely unpredictable time, perhaps | interleaved with actions on the main execution path. But it is a fact that many of us have at least some idea of what happens under the hood when we use

Bug in ghc-pkg on SunOS

I am using ghc-pkg on SunOS4 and get the following behavior when using 'ghc-pkg -g': ld: illegal option -- x ld: illegal option -- - ld: illegal option -- w ld: illegal option -- x ld: illegal option -- - ld: illegal option -- w My guess is that it is trying to build a .o file from a .a file

RE: Bug in ghc-pkg on SunOS

| system(ld -r -x -o ++ ghci_lib_file ++ |--whole-archive ++ batch_lib_file) It works with gld however! Maybe configure should insist on gld being there. /K ___ Glasgow-haskell-bugs mailing list [EMAIL PROTECTED]

Spam

Hi all, Sorry to bother you with a message about spam. I have noticed two things about this mailing list: * Every once in a while, we get messages like your e-mail is under consideration for sending to the list. This suggests that the mailing list is moderated, and that there is some

Re: Bug in library report

of compiler bugs which can make a | program return 'True' without actually executing the | program correctly. I do not understand what you mean here. Maybe an example helps? | With that modification, I strongly agree. I'm in! /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University

Re: lines/unlines and inverse

. (lines . unlines) == {equation 1} unlines . id == {id is unit of (.)} unlines I.e. in general, when f is g's left inverse: f . g == id Then the following equation holds automatically: g . f . g == g Regards, /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen

Re: Weird profiling behaviour

Ketil Z. Malde wrote: | I have what I think is a really strange problem. I | have a fair sized problem, which involves sorting a | data set, first on labels (which are Strings) and then | on scores (which are Ints). | | The strange thing is that string sorting is *vastly* | faster than

Re: Weird profiling behaviour

Ketil Z. Malde wrote: | (writing his own O(n log n) sortBy as we speak) It might be useful to look at Ralf Hinze's collection of sorting routines, available on his homepage: http://www.cs.uu.nl/~ralf/software.html#sort /Koen. ___ Haskell mailing

GHC on Cygwin

Dear Simon, Simon and Sigbjorn, I have finnaly managed to go through a complete make session without any errors! (There is a caveat: see end of mail). Some comments: In the end, it worked out-of-the-box. But it only did that after I had installed and reinstalled out of the necessary tools and

Re: Generating the n! permutations in Haskell

- favorite-way-to-do-permutations-discussion. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: Beginner's question: Memo functions in Haskell

between calls of f', so the introduction of the memo function has no effect. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo

Re: arrows

of monads (Sets for example) which can not be made instance of the current monad class in Haskell. Regards, /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell mailing list [EMAIL PROTECTED] http

Re: do notation and

collects CAFs, we have to add an extra reference to main, for example: main = do print start writeFile apa (show [1..]) main -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell

RE: do notation and

is the following: if Haskell does not care about sharing, why is the monomorphism restriction there? Regards, /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell mailing list [EMAIL PROTECTED] http

Re: do notation and

in GHC might actually introduce a very nasty space leak in existing programs! /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman

minimumBy and maximumBy

for this? Regards, /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell

Re: How to make Claessen's Refs Ord-able?

| I'd like to extend the Ref type for observable sharing | of Koen Claessen's Ph.D. thesis: to make it possible | for the Refs to be the keys for efficient finite maps. I did this in the Lava implementation. The Ref module I attach works in Hugs and GHC. /Koen. module Ref ( Ref

Re: Specifying Kinds of Types

!) There might be an easier workaround, too, but you get the idea. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell

Re: ST and IO. Two problems. Some old some new?

a typeCastIO :: a - IO b typeCastIO a = do set globalPolyVar a get globalPolyVar Which would be a disaster! | gensym :: () - Int | gensym = (...) Of course, we knew this could be done with unsafePerformIO already, no need to take in unsafeSTtoIO. /Koen. -- Koen Claessen http

Re: Reference types

this: liftRef :: MonadTrans t = Ref m a - Ref (t m) a liftRef ref = MkRef { readRef = lift (readRef ref) , writeRef = \a - lift (writeRef ref a) } Look, ma, no type classes! /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg

Re: RFC: Syntax for implicit parameter bindings

Ch. A. Herrmann proposed: | addBase{?base=7} 5 I like this! It is the least polluting syntax of all. /Koen. ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell

Implicit Parameters

recursion to solve this problem). My questiona are: Were the designers of the implicit parameters paper aware of this problem when they wrote the paper? If so, they probably did not think this was a big problem. Do people in general think this is a problem? /Koen. -- Koen Claessen http

GHCi Cygwin

it is a general fix, since Hugs seems to suffer from exactly the same problem...) Thanks, /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden. ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http

Bug in GHCi

Hi, This is a bug which has been in GHCi from the beginning. Bug === GHCi interprets a module while the compiled version is present and up-to-date. Details === When I (for example) have the following module structure: module A where ... module B where import A ... The

Re: FFI

Manuel M. T. Chakravarty wrote: | I don't think that it makes much sense coding on the | plain FFI unless there are reasons for avoiding an | extra tool or the binding is very small. Just my $0.02: I have used the plain FFI for larger projects. The initial reason I did this because my

Re: GHC Poll: scope in GHCi

| Does anyone have any better suggestions? I think any solution that leaves it transparent as to if it is a compiled or an interpreted module is fine. But I have understood that this is hard to achieve... /Koen. ___ Glasgow-haskell-users mailing

RE: GHC Poll: scope in GHCi

| I'm currently showing the scope in the prompt, with | the modules from which we're taking the exports only | surrounded by square brackets. It is nice to show the difference. What I am looking for however is to get everything defined in a compiled module into scope. One solution might be

Bug in hGetBufBA + hIsEOF

Hi, Given a file test of size 2342. The program Bug.hs behaves correctly (the result is (2048,384)), but when uncommenting the seemingly innocent line, the program behaves incorrectly (result is (2048,2048)), and the buffer is filled with garbage. main = do han - openFile test ReadMode

RealWorld?

Hi, I want to use the functions: hGetBufBA :: Handle - MutableByteArray RealWorld a - Int - IO Int hPutBufBA :: Handle - MutableByteArray RealWorld a - Int - IO () But as soon as I mention their types, 'RealWorld' is not in scope. In what module is this defined? /Koen.

Bug in GHCi

Hi, I discovered two bugs in GHCi. I am using GHC5.02 on Linux. The first bug has been there for some time now. If I start GHCi with a module `A.hs', which either does not exist itself, or which includes modules that not exist, then GHCi terminates with an error message. This is rather

ghc -O

the impossible error. /Koen. {-# OPTIONS -fglasgow-exts #-} {- module Parsek --- Author: Koen Claessen Date: 2001-01-27 Compliance: hugs -98 (needs forall on types) Licence:GPL Comments: This module

Re: Incoherence

John Hughes wrote: | `x := []' wouldn't be problematic, just monomorphic. | That is, x must be used consistently as a list of a | particular type. Just to check if I understand you correctly. In your proposal, does the following thing share `x'? let x = fac 100 in x + x (My understanding

RE: rank 2-polymorphism and type checking

Simon Peyton-Jones wrote: | So I'm interested to know: if GHC allowed | arbitrarily-ranked types, who would use them? I have certainly come across (very practical) situations where I would like to use rank-n types (with n 2). One example is the following. When using runST, I often end up

Re: Strange error in show for datatype

Olaf Chitil wrote: | Admittedly, many Haskell beginners fall into the `show | []' trap. Indeed. And this is a perfect example of the fact that all this bottom-dictionary passing does not work. The type of the list still matters though: Hugs show ([] :: [Char]) \\ Hugs show ([] ::

Flags in GHCi

Hi, I noticed a difference in behavior between running: ghci -package utils And: ghci ... Prelude :set -package utils On our system, the first one works (it finds all the right dynamic libraries and stuff), but the second one doesn't (it cannot find libreadline.so, and other

Socket documentation

Hi, The function mkPortNumber is gone from the Socket library: Prelude :t Socket.mkPortNumber interactive:1: Variable not in scope: `Socket.mkPortNumber' Though it is still mentioned in the documentation for GHC-5.02. /Koen. ___

Re: FFI in GHCi 5.02

the FFI should work (but it doesn't) * or it does not work (but GHC panics anyway) In either case this is a bug... /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL PROTECTED] - Chalmers

FFI in GHCi 5.02

Hi, When I load tha Yahu package [1] in GHCi 5.02 on a SParc running Solaris, I get the following message: scooter bin/yahu.new Resources/YahuNew/Examples/Balls.hs ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 5.02, for Haskell 98. / /_\\/ __ /

Bug in Time module

. I guess this is a bug. I am running ghc-5.00.2 on Linux. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL PROTECTED] - Chalmers University of Technology, Gothenburg, Sweden

RE: Bug in Time module

| I'm not sure it's a bug - Haskell 98 doesn't require | that the TimeDiff value returned from diffClockTimes | is normalised in any way, and it can't be done in | general of course because months and years have | different numbers of days, even minutes have different | numbers of seconds

A monad for type casting

Objects from two different O-threads. -- -- I conjecture that it is impossible to implement this module in -- pure Haskell with any of the known safe extensions. (So it is -- even impossible if you are allowed to use the ST monad.) -- -- Koen Claessen, 19 November 2000

Re: Application letters at the Haskell workshop: suggestion

Alastair David Reid wrote: | existential types, functional dependencies, other | experimental-but-apparently-crucial features [...] : | I do use the IO monad, IORefs (sparingly), constructor | classes, lots of libraries, the foreign function | interface (lets you call C and C++), parser

Eq Socket

Apa.hs, I get: Apa.hs:6: No instance for `Eq Socket' arising from use of `==' at Apa.hs:6 in the definition of function `foo': x == x /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL PROTECTED

Socket

the Select module. Has anybody had this problem before, and, if so, what could be a solution? Thanks, /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL PROTECTED] - Chalmers University

Re: Random Generator

Hannah Schroeter wrote: | * thread a random generator through randomPick, giving it the | type signature: | randomPick :: (RandomGen g) = g - Int - [a] - ([a], g) It is not necessary to thread the random generator through. This is the reason why the split function exists in the Random

Generics

Hi, I discovered some mistakes in Chapter 7.17, Generics, in the GHC documentation on the web. In 7.17.2, it says: {| and {| This should be {| and |} of course. In 7.12.3, there is a little code fragment, that looks like this: class Foo a where op1 :: a - Bool op

Package

Hi, I wonder if it is possible to use one's own packages.conf file, so that users can make their own packages? It would be nice if there were a flag to ghc and to ghc-pkg that also allowes using a local package file. /Koen. ___ Glasgow-haskell-bugs

RE: Package

its other | bits and pieces are, though. But one could *add* one's own local package.conf file, in addition to the global one. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL PROTECTED

GHCi and .o files

, it does not recognize it as a dynamic object file. (Which it strange, because there is an error message that identifies .so files as valid arguments to GHCi...) /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL PROTECTED

FFI and Control-C

Hi, I recently started experimenting using the FFI in GHC and GHCi. In GHCi, one would like to press control-C in the middle of a computation, and get back to the prompt. It is however hard to understand how control-C and the foreign function calls interact. I noticed that GHCi does not react

Bug in type inference

Hi, If I load the following module: module Apa where import ST apa = newSTRef () return () into ghci -package lang, and I ask for the type of apa, the following happens: Apa :t apa ST () () This is obviously wrong, it should be (as hugs -98 says): Apa :t apa apa :: ST a ()

RE: infelicity in module imports

Simon Peyton-Jones wrote: | [..modules..] So here's the message anyway. I don't | think it's controversial, since it's the outcome the | cognoscenti were seeking, and no one else will care. That is not true! I do care! :-) Often, after having been bitten by a misunderstanding of the

RE: infelicity in module imports

Simon Peyton-Jones wrote: | Could I ask you to try one more time, with the current | draft report? available at | http://research.microsoft.com/~simonpj/haskell98-revised I did that before I wrote my e-mail. | Can you suggest ways in which it could be made | clearer? I've filled in the

Fixity declarations

Hi all, The topic is fixity declarations for operators. The report says: Fixity is a property of a particular entity (constructor or variable), just like its type; fixity is not a property of that entity's name. It is possible to define fixities for locally declared bindings: f x y

Bug in GHCi

the evaluation of the system call. I do not think it makes much sense for me to send you my code, since: 1. This bug occurs with a lot of different code I have. 2. The particular code I have is HUGE. We are running Linux. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46

Re: Negatively recursive data types

Keith Wansbrough wondered: | Does anyone have an example of a useful data type | involving negative recursion? Here is an example straight from practice. If we want to implement a datatype of predicate logic formulas, it is convenient to use higher-order syntax: type Name = String

Re: binary files in haskell

also say: Byte.write Byte.read So that the context (Byte.) can be left out when unambiguous, and one can just say: write read /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL PROTECTED

Re: Specifications of 'any', 'all', 'findIndices'

* implementation, and the compiler writer is free to implement this in whatever way (s)he likes. As long as the implementation has the same functional behavior as the specification in the report. /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen phone:+46-31-772 5424 mailto:[EMAIL

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