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Today's Topics:
1. Re: Does haskell have to have values? (Stephen Tetley)
2. Re: Does haskell have to have values? (Mike Meyer)
3. how to feel free of the Implementation of Data structure (???)
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Message: 1
Date: Wed, 23 Mar 2011 22:52:12 +0000
From: Stephen Tetley <[email protected]>
Subject: Re: [Haskell-beginners] Does haskell have to have values?
Cc: Haskell Beginners List <[email protected]>
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=ISO-8859-1
On 23 March 2011 20:17, Mike Meyer <[email protected]> wrote:
>
> (+) ? ? accepts one argument and returns a function that accepts one
> ? ? ? ?argument and returns a zeroadic function that returns the
> ? ? ? ?value of the sum of the two arguments.
> (+ 5) ? accepts one argument and returns a zeroadic function that ...
> (3 + 5) a zeroadic function that returns 8
>
> So the question is - is there any advantage or harm in this way of
> looking at values?
Be careful, wise voices appear to conclude it is harmful:
http://conal.net/blog/posts/everything-is-a-function-in-haskell/
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Message: 2
Date: Wed, 23 Mar 2011 20:36:33 -0400
From: Mike Meyer <[email protected]>
Subject: Re: [Haskell-beginners] Does haskell have to have values?
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII
On Wed, 23 Mar 2011 22:52:12 +0000
Stephen Tetley <[email protected]> wrote:
> On 23 March 2011 20:17, Mike Meyer <[email protected]> wrote:
> > So the question is - is there any advantage or harm in this way of
> > looking at values?
[as nullary functions]
> Be careful, wise voices appear to conclude it is harmful:
> http://conal.net/blog/posts/everything-is-a-function-in-haskell/
True, they do appear to have concluded that this is harmful. But this
article is more about how people get to that harmful conclusion than
about what's harmful about it. While that answers my question, I'd be
interested in seeing more about why it's harmful.
thanks,
<mike
--
Mike Meyer <[email protected]> http://www.mired.org/consulting.html
Independent Software developer/SCM consultant, email for more information.
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Message: 3
Date: Thu, 24 Mar 2011 18:34:57 +0800
From: ??? <[email protected]>
Subject: [Haskell-beginners] how to feel free of the Implementation of
Data structure
To: haskell beginner <[email protected]>
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=UTF-8
1. To use the Data.List is so easy as it's in the 'prelude'. but when
I want to get some elements by index, I need to use Array, or sometime
I want to use ByteString for some good reason.
We all know It's some 'linear ordered things'. Is there some method
for me to use just one form of 'list' with every possible function on
it.
2.
f1 :: (Integral a) => a -> String
f2 :: (Integral a) => String -> a
pipe = f1 . f2
It is clear that pipe is String -> String,
but.(1)How can I know what instance that 'a' is.
(2)How can I determine what instance of 'a' is.
--
----------------
???
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