Re: [Haskell-cafe] AlternativePrelude extension
Laurdag 16. januar 2010 22.40.17 skreiv Malcolm Wallace:
I'm thinking the syntax would be something like
AlternativePrelude=MyPrelude.
There is a general principle that the semantics of a program should be
completely described by the source code itself, and not dependent on
options that may or may not be specified elsewhere. Hence, the idea
of adding {-# LANGUAGE #-} pragmas, so that the source code is self-
contained.
Specifying {-# LANGUAGE NoImplicitPrelude #-} together with import
MyPrelude satisfies this principle, as does {-# LANGUAGE
AlternativePrelude=MyPrelude #-} in all files where it matters. But
the difference in usability is slight.
If you are suggesting that {-# LANGUAGE AlternativePrelude=MyPrelude
#-} should somehow escape the scope of the module it appears in, then
I think we heading for less firm ground.
Regards,
Malcolm
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Having a LANGUAGE pragma, or indeed any pragma, escape the module it's used in
would be pretty silly, wouldn't it?
In principle I'm a fan of the LANGUAGE pragmas. Self-contained source is
usually much easier to read that source that depends on whatever command the
author used to build the thing.
However, the option to set language extension globally is still available,
either as an option to the compiler when building, or in the cabal file
describing the package. Allowing an alternative prelude in this fashion makes
it easier to switch out the standard for alternatives in existing projects
just to see what might happen, how things are changed or just for giggles. It
might not be advisable to do so in code you plan on unleashing on the world,
but it would make experimenting with alternatives cheaper than it currently
is.
--
Sjur Gjøstein Karevoll
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[Haskell-cafe] AlternativePrelude extension
Here's an idea I'd like to air: A new extension called AlternativePrelude. Like the NoImplicitPrelude extension we have already, this would disable implicitly importing the Prelude in every other module, but would also implicitly import a substitute. The purpose is to make it easier to play around with alternative preludes. Today we have to specify NoImplicitPrelude, but also explicitly import our alternative everywhere, making the transition between the different preludes that much more painful. With this new extension, the alternative prelude can be specified in the cabal file, or on the command line when building. This will hopefully make the alternative prelude efforts a little bit more mainstream, giving us more data we can use to consider modifications to the current standard prelude. I'm thinking the syntax would be something like AlternativePrelude=MyPrelude. This is new among the extensions in that it requires a parameter. An alternative is an ImplicitImport extension that doesn't disable the implicit importing of the Prelude, but while this does serve the same purpose as the AlternativePrelude proposal, I think it might be easier to use it for nefarious purposes. -- Sjur Gjøstein Karevoll ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Learning Haskell
må. den 23.03.2009 klokka 20:08 (-0700) skreiv Tom.Amundsen: How long did it take you to become proficient in Haskell? By that, I mean - how long until you were just as comfortable with Haskell as you were with your strongest language at that time? It's been nine months since I first started learning, but for about five months in the middle I didn't do any Haskell hacking (or much hacking at all). Measuring completeness of knowledge, Haskell still ranks below Python and Java, but measuring ability to solve a given problem Haskell comes out on top. Of course, I've only been programming for two years total... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] about Haskell code written to be too smart
I know what you're saying, in a way. There is much haskell code that's completely illegible to me. I would say there is a difference between Haskell and Perl though, in that Perl code is too smart aka. clever, while Haskell code is usually simply, well, too smart. This means code written using aspects of covariant generalized applicative combinators in a closed Hillbert-space like continuous field ring, and other similar nonsense. There was a time when monadic parser combinator sounded equally nonsensical to me. It doesn't anymore, and I'm a better programmer for it, being able to reduce one of my earliest Haskell programs from 200 to 20 lines using that knowledge alone while making it more comprehensible and maintainable at the same time. The difference between Haskell and Perl is that Haskell programmers use clever ideas while Perl programmers use clever abuse of syntax. Ideas, at least, you have a hope of understanding sometime in the future. ty. den 24.03.2009 klokka 18:41 (+0100) skreiv Manlio Perillo: Hi. In these days I'm discussing with some friends, that mainly use Python as programming language, but know well other languages like Scheme, Prolog, C, and so. These friends are very interested in Haskell, but it seems that the main reason why they don't start to seriously learning it, is that when they start reading some code, they feel the Perl syndrome. That is, code written to be too smart, and that end up being totally illegible by Haskell novice. I too have this feeling, from time to time. Since someone is starting to write the Haskell coding style, I really suggest him to take this problem into strong consideration. Manlio ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Sugestion for a Haskell mascot
I've unconciously conditioned myself to think about rabbits with nukes each time I think about monads. Warm fuzzy things launching the missiles indeed. On Friday 13 March 2009 02.38.29 Richard O'Keefe wrote: On 12 Mar 2009, at 11:08 pm, Satnam Singh wrote: I agree that looking for a mascot that is inspired by laziness is a bad idea from a P.R. perspective (I am tired of people walking out the room when I give Haskell talks to general audiences and explain lazy evaluation). Perhaps we should call it Just-In-Time evaluation. As for mascots, let's take a photo of Simon Peyton Jones, shrink him to hobbit size, give him furry feet, and announce that here is one of the warm fuzzy things we have in mind when we use monads. (:-) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Sjur Gjøstein Karevoll sjurberen...@gmail.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
