Re: [Haskell-cafe] Tutorial uploaded
On Wed, 21 Dec 2005, Udo Stenzel wrote: > Donn Cave wrote: > > Meanwhile, that fellow evidently didn't write any compiler in Haskell > > at all. Better a C++ program than a Haskell program that offends you? > > But that's besides the point. The conviction that a parser or lexer or > prettyprinter means IO is simply wrong, and imho a tutorial should show how > much is purely functionally possible before introducing control flow, > mutable variables and all the other ugliness. It's more productive this > way. Btw. Simon Thompson states in his book, that he found it didactically infelicitous to introduce recursion before higher order functions because that let beginners stick to case discriminations and recursive programming instead of taking advantage of functions like 'map', 'iterate', 'fold' etc. I can confirm this experience and I think that it is similar to IO vs. non-IO. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Tutorial uploaded
Paul Moore <[EMAIL PROTECTED]> writes: > One thing I'd consider adding is something along the lines of a section: > == So how do I write "Hello, world"? == I've gone and done it. I've perhaps been heavy handed on the original page, so feel free to complain and/or fix it. -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Tutorial uploaded
> From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Daniel Carrera > > Hi all, > > I've finished a first draft of what I call "First steps in Haskell". > It's intended to be the very first thing a new user sees when they > decide to try out Haskell. > > http://www.haskell.org/hawiki/FirstSteps?action=show > > Thoughts and comments? There's not much wrong with doing a Hello World: main = putStrLn "Hello World" Or: fac n = if n <= 0 then 1 else n * fac (n-1) main = print (fac 12) Compiling, or at least running a haskell script (via runhaskell) should also get a mention, so you show how to achieve things outside of the interactive prompt. Alistair * Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. * ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Tutorial uploaded
On 12/20/05, Daniel Carrera <[EMAIL PROTECTED]> wrote:
> Hi all,
>
> I've finished a first draft of what I call "First steps in Haskell".
> It's intended to be the very first thing a new user sees when they
> decide to try out Haskell.
>
> http://www.haskell.org/hawiki/FirstSteps?action=show
>
> It's a bit longer than I'd like, but I don't inmediately see anything I
> can take out without losing something valuable (given the purpose of
> this document).
>
> Thoughts and comments?
It looks very good. The length isn't a problem to me, if anything I'd
be happy expanding a little.
One thing I'd consider adding is something along the lines of a section:
== So how do I write "Hello, world"? ==
Well, the first thing you need to understand that in a functional
language like Haskell, this is a harder question than it seems. Most
of the code you will write in Haskell is "purely functional", which
means that it returns the same thing every time it is run, and has no
side effects. Code with side effects is referred to as "imperative",
and is carefully isolated from functional code in Haskell.
To deal with the distinction between functional and imperative code,
Haskell uses a construct called the "IO monad". It's not hard to
understand - basically, it's just a way of "wrapping up" imperative
code so that there's a clear boundary between it and functional code -
but most tutorial presentations of Haskell start with functional code,
and introduce the IO monad later.
As a taster, though, here is "Hello, world" in Haskell:
{{{
module Main where
main :: IO ()
main = putStrLn "Hello, World!"
}}}
Put this in a file called hello.hs, and compile it with `ghc -make
hello.hs -o hello`. You'll get an executable called hello (or
hello.exe on Windows). Run it to see the output.
There will be plenty more on writing standalone programs, IO, and
other aspects of the IO monad, as you learn more about Haskell.
The point is, people *will* want to write "hello, world", so don't put
them off by making it seem "hard". Show them how, explain where they
will find out more, and explain why things like this come naturally at
a later stage when learning Haskell than they do with, say, C.
Paul.
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Re: [Haskell-cafe] Tutorial uploaded
[EMAIL PROTECTED] wrote: hi daniel, the link about german (deutsch) haskel courses is in fact a link to a dutch (nederlands) page. For the rest it looks good! Thanks. Fixed. I removed the wrong link. Cheers, Daniel. -- /\/`) http://oooauthors.org /\/_/ http://opendocumentfellowship.org /\/_/ \/_/I am not over-weight, I am under-tall. / ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Tutorial uploaded
hi daniel, the link about german (deutsch) haskel courses is in fact a link to a dutch (nederlands) page. For the rest it looks good! Peter > Hi all, > > I've finished a first draft of what I call "First steps in Haskell". > It's intended to be the very first thing a new user sees when they > decide to try out Haskell. > > http://www.haskell.org/hawiki/FirstSteps?action=show > > It's a bit longer than I'd like, but I don't inmediately see anything I > can take out without losing something valuable (given the purpose of > this document). > > Thoughts and comments? > > Cheers, > Daniel. > -- > /\/`) http://oooauthors.org > /\/_/ http://opendocumentfellowship.org > /\/_/ > \/_/I am not over-weight, I am under-tall. > / > ___ > 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
