[Haskell-cafe] Re: [Haskell] ANNOUNCE: jhc 0.6.1
Switching to Haskell Cafe; I hope you read that list, John, since it seems more suitable to this kind of question. John Meacham wrote: Hi, this is to announce the release of jhc 0.6.1. The jhc homepage with distribution information is at http://repetae.net/computer/jhc/ The main new feature in this release is a much simplified cross-compilation mechanism. While cross-compilation was always possible with jhc, it used to involve manually copying the C file and calling gcc with the right options on it, now this is taken care of by jhc. A (popular) example would be setting up an iPhone cross compilation target. For instance with the SDK setup I have, I would simply add the following to a file ~/.jhc/targets.ini [iphone] cc=arm-apple-darwin cflags+=-I/usr/local/arm-apple-darwin/include merge=le32 then you can compile iphone binaries with ; jhc --cross -miphone HelloWorld.hs the targets mechanism is extensible at run-time and I have included native unix, win32, osx-intel and osx-powerpc targets. But certainly many more interesting ones are possible. Some I have tested have been a nokia N770 as a target and an atheros MIPS based router running dd-wrt. Maximum coolness! When you were targeting the nokia, how did you handle the radically different user interface? Did you have to establish a mapping from one of the Haskell UI packages to the Nokia equivalents? If so, which one did you pick, and how much time did it take? I'd love it if I could get this working for the Palm Dave Barton (soon to be) University of Toronto ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Cabal: error on configure
OK, I suspect this is a real newbie error, but please have mercy. I have downloaded and installed cabal (at least it responds to the --help command from the command line). Yet when I do, say (to give a real example): cabal configure parameterized_ data (having done he fetch) I get this error: cabal.exe: Using 'build-type Custom' but there is no Setup.hs or Setup.lhs script.' When I download the package manually and look, there is a perfectly servicable Setup.hs script, which I call manually. So what gives? Dave Barton ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Do you trust Wikipedia?
The trustworthy articles on Wikipedia have references that can be checked, and read. The ones without references are not to be trusted.. Dave Barton - Original Message - From: Philippa Cowderoy [EMAIL PROTECTED] To: PR Stanley [EMAIL PROTECTED] Cc: haskell-cafe@haskell.org Sent: Thursday, October 18, 2007 10:28 AM Subject: Re: [Haskell-cafe] Do you trust Wikipedia? On Thu, 18 Oct 2007, PR Stanley wrote: Hi Do you trust mathematical materials on Wikipedia? Paul To a first approximation - trust but verify. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functions with side-effects?
Wolfgang Jeltsch writes: - Original Message - Am Mittwoch, 21. Dezember 2005 13:15 schrieb Creighton Hogg: [...] Monads, I believe, can be just thought of as containers for state. I would say that you are talking especially about the I/O monad here. A monad as such is a rather general concept like a group is in algebra. While this is correct, I'm afraid that for most of us it is a flavorless answer. I wish I had the mathematical mind that made the word group in this context instantly intuitively recognizable, but I don't. I think Phil Wadler said it best when he said that a monad is a *computation*. If a function is a mapping between input and output values, a computation is both an invocation of a function and the provision of values --- which can include state, ordering, and many other things. Of course, I'm a Phil Wadler fan anyway. The important point of the integration of imperative programming in Haskell is not that it's done using monads. The point is that you have a specific type (IO) whose values are descriptions of I/O actions, and some primitive operations on IO values. The IO type together with two of these primitive operations forms a monad but this is secondary in my opinion. Yes and no. It is important for me, at least, to continue to grasp that IO is just not a functional thing --- it is not captured intuitively in a function. Rather, it is a computation --- IO doesn't make sense until it executes in an environment which it can effect. This is why we capture IO (as well as other computational concepts) in monads, and why (again IMHO) mondadic IO is so much more effective and intuitive than continuation style IO or stream based IO ever was. Dave Barton ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Updating the Haskell Standard
John Goerzen writes: There was a brief discussion on #haskell today about the Haskell standard. I'd like to get opinions from more people, and ask if there is any effort being done in this direction presently. snip I know that some people would like to hold off on such a process until their favorite feature (we'll call it feature X) is finished. I would argue that incremental addendums to the standard should be made more frequently, so that new features can be standardized more easily. Thoughts? I can contribute some experience from commercial standardization efforts. ANSI, IEEE, and ISO standards require re-ballotting every five years, otherwise the standards lapse. Reballotting may or may not be accompanied by changes in the standard; for a standard as complex as a language, new versions at least every five years seems to be fairly common with newer standards (ANSI C has not changed in newer standardization ballots as far as I know). The trade-off for standards is between stability for tool developers and learners and stagnation. If the standard changes too often, there will be only one developer (the one effectively in charge of the standard) and it will tend to not be taught anywhere (because what students learn is obsolete too quickly). If the standard is unchanged too long, it becomes irrelevant and obsolete and no one pays attention to it. Five years is what the general industry seems to have settled on as a good average, but it may or may not apply here; the circumstances are different. Developers of Haskell are pretty much volunteers and academics; that changes things. On the other hand, it is a rapidly developing field. How all this shakes out is something for the community at large to decide; however, that is what happens in other standards bodies. Dave Barton EDAptive Computing ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Haskell] Newbie : How come that cyclic recursive lists areefficient ?
Benjamin Fransen writes: There *is no* difference between the two if one views them as pure mathematical values. Questions of run time speed or memory usage, i.e. efficiency (which your original question was about) are clearly outside the realm of pure values, and thus we may perceive them as distinct in this wider setting. My favourite analogy for this is the old joke about a topologist being a person who cannot see any difference between a cup and a doghnut. The engineer's response, of course, at the thought of ignoring questions about run time speed and memory usage, is that a topologist is a person who doesn't know his ass from a hole in the ground. (I was told this quote was actually from abstract algebraists, when confronted by the famous description of a topologist, but what the heck.) Dave Barton EDAptive Computing ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The implementation of functional languages
John Meacham writes: I am looking for the book The implementation of Functional Programming languages by S. L. Peyton Jones. This book is out of print and currently there is no electronic version of it. The Haskell bookstore folk are working on reconstructing it and making it available for print-on-demand, http://www.cafepress.com/haskell_books/, but it's not clear when exactly it will be available. Your other option is to try to find a used copy, but they are pretty expensive. I am working on getting that book available in the haskell bookstore. I searched quite a while before I found a used printed copy at a reasonable price and my search was part of my motivation for creating the bookstore. It is a bit trickier than the other books on the site because I only have a scanned in copy of the print version to work with, rather than LaTeX source. but I should have time this week to get it online. John My wife (mainly) and I, with Simon's permission, have been working on getting a web-enabled version of this available for quite some time. It hovers on the brink of completion, and should be there Real Soon Now as well. This will include a web enabled table of contents and next and back buttons. If I'd known how much time she would put in, I'd have never asked her for a small favor... Dave Barton EDAptive Computing ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Graphical Programming Environments (was: ANNOUNCE: Release of Vit al, an interactive visual programming environment for Haskell)
I love religious wars. Having been around awhile, I make a prediction. This will thrash a while, those who like graphical environments will make their points, those who like textual environments will make their points, no one will convince anyone else, and eventually it will die down. In fact (in my opinion), people operate differently. Some operate better graphically, some operate better textually, and I'm glad both tools are available. Me, I'm a text person, but I know folks who think better in pictures, bless 'em. Let the games begin. Dave Barton EDAptive Computing ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Typing units correctly
Tom Pledger writes: In both of those cases, the apparent non-integer dimension is accompanied by a particular unit (km, V). So, could they equally well be handled by stripping away the units and exponentiating a dimensionless number? For example: (x / 1V) ^ y I think not. The "Dimension Types" paper really is excellent, and makes the distinction between the necessity of exponents on the dimensions and the exponents on the numbers very clear; I commend it to everyone in this discussion. The two things (a number of "square root volts" and a "number of volts to an exponent" are different things, unless you are simply trying to represent a ground number as an expression! Dave Barton * [EMAIL PROTECTED] )0( http://www.averstar.com/~dlb ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
