Cristian Baboi [EMAIL PROTECTED] wrote:
How about
a :: Something
a = let x = x in x
:t a
would give (a - [a]), not Something, or am I mistaken?
--
(c) this sig last receiving data processing entity. Inspect headers for
past copyright information. All rights reserved. Unauthorised
It give Something.
On Mon, 31 Dec 2007 10:27:38 +0200, Achim Schneider [EMAIL PROTECTED] wrote:
Cristian Baboi [EMAIL PROTECTED] wrote:
How about
a :: Something
a = let x = x in x
:t a
would give (a - [a]), not Something, or am I mistaken?
Information from NOD32
Cristian Baboi [EMAIL PROTECTED] wrote:
It give Something.
You're right, I'm thinking too lispy. The point is that it doesn't have
to be passed an x to be infinite, and that a by itself is fully
polymorphic.
It seems like you're trying to solve the halting problem. Slurping any
infinite data
On Mon, 31 Dec 2007 10:40:13 +0200, Achim Schneider [EMAIL PROTECTED] wrote:
It seems like you're trying to solve the halting problem.
I didn't know that.
Slurping any
infinite data structure makes your program perform rather badly, I'm
afraid.
What is infinite in let x = x in x ?
What I
Cristian Baboi [EMAIL PROTECTED] wrote:
What is infinite in let x = x in x ?
^ ||
|___/|
\/
--
(c) this sig last receiving data processing entity. Inspect headers for
past copyright information. All
Achim Schneider [EMAIL PROTECTED] wrote:
Cristian Baboi [EMAIL PROTECTED] wrote:
What is infinite in let x = x in x ?
^ ||
|___/|
\/
a = let x = x in x
is actually only quite verbose for
a =
On Mon, 31 Dec 2007 10:59:28 +0200, Achim Schneider [EMAIL PROTECTED] wrote:
Achim Schneider [EMAIL PROTECTED] wrote:
Cristian Baboi [EMAIL PROTECTED] wrote:
What is infinite in let x = x in x ?
^ ||
|___/|
Cristian Baboi [EMAIL PROTECTED] wrote:
On Mon, 31 Dec 2007 10:59:28 +0200, Achim Schneider [EMAIL PROTECTED]
wrote:
Achim Schneider [EMAIL PROTECTED] wrote:
Cristian Baboi [EMAIL PROTECTED] wrote:
What is infinite in let x = x in x ?
^ ||
On Mon, 31 Dec 2007 11:14:39 +0200, Achim Schneider [EMAIL PROTECTED] wrote:
Cristian Baboi [EMAIL PROTECTED] wrote:
I could have written this instead:
a :: Something
a = a
Which is nicer than undefined.
[EMAIL PROTECTED] ~ % ghci
GHCi, version 6.8.2: http://www.haskell.org/ghc/ :? for
On Mon, 31 Dec 2007 11:14:39 +0200, Achim Schneider [EMAIL PROTECTED] wrote:
Cristian Baboi [EMAIL PROTECTED] wrote:
On Mon, 31 Dec 2007 10:59:28 +0200, Achim Schneider [EMAIL PROTECTED]
wrote:
I could have written this instead:
a :: Something
a = a
Which is nicer than undefined.
Cristian Baboi [EMAIL PROTECTED] wrote:
Well, it depends on what you think is nicer.
For me it looks shorter than undefined and it don't rely on the
library.
Well, for me undefined doesn't throw undeterministic behaviour at me
(throwing a stack overflow sooner or later or not, depending on
On 12/30/07, Cristian Baboi [EMAIL PROTECTED] wrote:
Thank you.
data Something = This | S Something
ppp :: Something - String
ppp This =
ppp (S x) = 'S':(ppp x)
How can I prevent one to pass 'let x = S x in x' to ppp ?
{-# LANGUAGE GADTs, EmptyDataDecls #-}
data Z
data S a
data
Nice! Thank you.
On Mon, 31 Dec 2007 12:56:42 +0200, Ryan Ingram [EMAIL PROTECTED]
wrote:
On 12/30/07, Cristian Baboi [EMAIL PROTECTED] wrote:
Thank you.
data Something = This | S Something
ppp :: Something - String
ppp This =
ppp (S x) = 'S':(ppp x)
How can I prevent one to pass
Twan van Laarhoven wrote:
Robin Green wrote:
I am proving various statements relating to applicative functors, using
the Coq proof assistant (I am considering only Coq terms, which always
terminate so you don't have to worry about _|_). However, I'm not sure
how to go about proving a certain
I forgot 2 things:
The distinction between '=' and '==' is much like in C, although mixing
them up is not so dangerous like in C. ':=' and '=' like in Wirth
languages would be nicer.
Strangely nobody reacted on this. That a=a+1 is an infinite recursion here
(but _|_ obviously not
On Mon, 31 Dec 2007 14:36:02 +0200, Joost Behrends [EMAIL PROTECTED]
wrote:
I forgot 2 things:
The distinction between '=' and '==' is much like in C, although mixing
them up is not so dangerous like in C. ':=' and '=' like in Wirth
languages would be nicer.
Strangely nobody reacted on
On Dec 30, 2007 6:24 PM, Joost Behrends [EMAIL PROTECTED] wrote:
I've already browsed through the docomentation of all that. Sorry, but i will
not use WASH. I like things to be direct, to write p { ... } or similar
things instead of p ... /p is worsening things for me.
Haskell is not a good
Isaac Dupree wrote:
Unfortunately, I get puzzling type errors if I annotate either one of
them with their type (e.g.
(Applicative f) = f (a - b) - f a - f (Int, b)
) in an expression. The very answer doesn't seem to typecheck.
:t \f x - fmap ((,) (0::Int)) (f * x) :: (Applicative f) = f (a1
Twan van Laarhoven wrote:
Isaac Dupree wrote:
Unfortunately, I get puzzling type errors if I annotate either one of
them with their type (e.g.
(Applicative f) = f (a - b) - f a - f (Int, b)
) in an expression. The very answer doesn't seem to typecheck.
:t \f x - fmap ((,) (0::Int)) (f * x)
Hi
I'm learning Haskell through writing a compiler. I'm seeing huge memory
use in a function which converts the dataflow graph to the form required
by Data.Graph. It needs to return a map from dataflow nodes to Vertexs,
a map in the other direction, and the list of edges (as Vertex pairs).
Hi,
So how, prey tell, do you factor out an expression which includes
p.../p? It is not Haskell,
Haskell has no power there. Surely
learning that mapping is easier than building your own (which will
doubtlessly be worse (no
offense, that's the first law of library use)).
And since you
Ben Challenor wrote:
Hi
I'm learning Haskell through writing a compiler. I'm seeing huge
memory use in a function which converts the dataflow graph to the form
required by Data.Graph. [...]
I assume the allocation is being garbage-collected pretty quickly,
because a) 6,616,297,296 bytes is
Hello Cristian,
Sunday, December 30, 2007, 8:16:33 PM, you wrote:
Can you write the value of x to a file where x = (1:x) ?
yes, there are libraries that can do it
--
Best regards,
Bulatmailto:[EMAIL PROTECTED]
___
Cristian Baboi [EMAIL PROTECTED] wrote:
What is more strange is that a = a + 1 and a = 1 + a are somehow
distinct. The second give a stack overflow almost instanly, but the
first don't.
That's because what the runtime does looks in the second case like
a = 1 + 1 + 1 + 1 + 1 + ... + a ...
and
On Dec 31, 2007, at 6:50 AM, Cristian Baboi wrote:
On Mon, 31 Dec 2007 14:36:02 +0200, Joost Behrends [EMAIL PROTECTED]
wrote:
I forgot 2 things:
The distinction between '=' and '==' is much like in C, although
mixing
them up is not so dangerous like in C. ':=' and '=' like in Wirth
Achim Schneider [EMAIL PROTECTED] wrote:
That's not specified though, the runtime could choose to let + force
the two chunks the different way round.
And that is probably also the reason why [1..] == [1..] is _|_.
Is Something that can be, in any evaluation strategy, be bottom, is
bottom
On Dec 31, 2007, at 9:53 AM, Paul Johnson wrote:
I'd advise against trying to make your program stricter because you
might suddenly find yourself building an entire 6GB structure in
memory before traversing it, which would not be a Good Thing.
I disagree. It might be the case that the
Jake McArthur [EMAIL PROTECTED] wrote:
I disagree. It might be the case that the _contents_ of the data
structure are lazy, in which case I would say the relevant
constructor parameters should be made strict. As long as the
structural parts are still lazy it should be okay.
And there's
L.Guo [EMAIL PROTECTED] wrote:
What should I do then ?
Use fromIntegral.
In general, conversion functions are conventionally named fromXXX, and
not toXXX, to emphasise functionality somewhat when using them.
--
(c) this sig last receiving data processing entity. Inspect headers for
past
2007/12/31, L.Guo [EMAIL PROTECTED]:
Hi MailList Haskell-Cafe:
I am a new haskeller. And was farmilar with C.
When tring to do some calculate, like this:
input = 5 :: Int
factor = 1.20 :: Float
output = factor ** (toFloat input)
I found that I do not know any function could do just what
Ah, thanks, it is my fault, for mis-understanding the hint from GHC.
And what is the difference between fromIntegral and fromInteger ?
--
L.Guo
2008-01-01
-
From: Mark T.B. Carroll
At:
In addition to the other replies, take a look at this wiki page for
more conversion advice:
http://www.haskell.org/haskellwiki/Converting_numbers
Kurt
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
On Dec 31, 2007, at 12:50 , L.Guo wrote:
And what is the difference between fromIntegral and fromInteger ?
Integer is a specific single type: unlimited-precision integers.
Integral is a typeclass which includes, among others: Integer, Int
(integers represented in machine words, so either
Joost Behrends wrote:
We read
data Pair a b = Pair a b
in YetAnotherHaskellTutorial. And that is all ! If we omit data here, this
would be a silly pleonasm. And no single word about this strange behavior of
data in every tutorial i read.
When learning a language, I find it useful to
On 31 Dec 2007, at 10:43 AM, Achim Schneider wrote:
Achim Schneider [EMAIL PROTECTED] wrote:
That's not specified though, the runtime could choose to let + force
the two chunks the different way round.
And that is probably also the reason why [1..] == [1..] is _|_.
Is Something that can
Jonathan Cast [EMAIL PROTECTED] wrote:
On 31 Dec 2007, at 10:43 AM, Achim Schneider wrote:
Achim Schneider [EMAIL PROTECTED] wrote:
That's not specified though, the runtime could choose to let +
force the two chunks the different way round.
And that is probably also the reason
On 31 Dec 2007, at 1:33 PM, Achim Schneider wrote:
Jonathan Cast [EMAIL PROTECTED] wrote:
On 31 Dec 2007, at 10:43 AM, Achim Schneider wrote:
Achim Schneider [EMAIL PROTECTED] wrote:
That's not specified though, the runtime could choose to let +
force the two chunks the different way
On Dec 31, 2007, at 11:21 AM, Achim Schneider wrote:
Jake McArthur [EMAIL PROTECTED] wrote:
I disagree. It might be the case that the _contents_ of the data
structure are lazy, in which case I would say the relevant
constructor parameters should be made strict. As long as the
structural parts
Jonathan Cast [EMAIL PROTECTED] wrote:
[...]
Right click - Color Label - Red.
--
(c) this sig last receiving data processing entity. Inspect headers for
past copyright information. All rights reserved. Unauthorised copying,
hiring, renting, public performance and/or broadcasting of this
Small correction - the extensions listed at the bottom weren't
necessary. I had attempted to define a relationship among tables
automatically as:
instance (HasField fk child, HasField pk parent, HasRelation pk fk)
= HasRelation parent child
But that was redundant with the signature on
40 matches
Mail list logo
