Another belated reply to an old thread...
Andrew Pimlott wrote:
> On Fri, Nov 18, 2005, Paul Hudak wrote:
> > unwind :: Expr -> Expr
> > unwind (Add e1 e2) = Add (unwind e1) (unwind e2)
> > unwind (Rec fe)= x where x = unwind (fe x)
> > unwind e = e
>
> Since this discussion started
On Sunday 27 November 2005 11:28, [EMAIL PROTECTED]
wrote:
> Andrew Pimlott:
>
> //about my highly spiritual essay on lazy computing of PI//:
> > In addition to being clever and terribly funny, the conclusion
> > foreshadows (inspired?) later work on Enron [1].
>
> Come on, it is improbable that M
| Andrew Pimlott:
| //about my highly spiritual essay on lazy computing of PI//:
|
| > In addition to being clever and terribly funny, the conclusion
| > foreshadows (inspired?) later work on Enron [1].
|
| Come on, it is improbable that Master Simon ever read my essay...
I hadn't before, but I
Andrew Pimlott:
//about my highly spiritual essay on lazy computing of PI//:
In addition to being clever and terribly funny, the conclusion
foreshadows (inspired?) later work on Enron [1].
Come on, it is improbable that Master Simon ever read my essay...
No,... no comparison.
His work on c
On Fri, Nov 18, 2005 at 11:37:40AM -0500, Paul Hudak wrote:
> This is a very late response to an old thread...
ditto :-)
> > unwind :: Expr -> Expr
> > unwind (Add e1 e2) = Add (unwind e1) (unwind e2)
> > unwind (Rec fe)= x where x = unwind (fe x)
> > unwind e = e
Since this discus
On Sat, Nov 19, 2005 at 02:27:06AM +0100, Benjamin Franksen wrote:
> [You should read some of his papers, for instance "the most unreliable
> techique in the world to compute pi". I was ROTFL when I saw the title
> and reading it was an eye-opener and fun too.]
In addition to being clever and te
On Saturday 19 November 2005 11:56, Gracjan Polak wrote:
> 2005/11/19, Benjamin Franksen
>
> > [You should read some of his papers, for instance "the most
> > unreliable techique in the world to compute pi". I was ROTFL when I
> > saw the title and reading it was an eye-opener and fun too.]
>
> Car
http://users.info.unicaen.fr/~karczma/arpap/
On Sat, 19 Nov 2005, Gracjan Polak wrote:
2005/11/19, Benjamin Franksen
[You should read some of his papers, for instance "the most unreliable
techique in the world to compute pi". I was ROTFL when I saw the title
and reading it was an eye-opener
2005/11/19, Benjamin Franksen
> [You should read some of his papers, for instance "the most unreliable
> techique in the world to compute pi". I was ROTFL when I saw the title
> and reading it was an eye-opener and fun too.]
>
Care to post a link? Seems interesting, but unknown to google :)
--
G
On Saturday 19 November 2005 02:16, Greg Woodhouse wrote:
> --- [EMAIL PROTECTED] wrote:
> > fix f = f (fix f) -- Here you have your Y. No typeless lambda.
> >
> > g f n = n : f n-- This is a generic *non-recursive* `repeat`
> > ones = fix g 1 -- Guess what.
>
> Very nice! I honestly woul
--- [EMAIL PROTECTED] wrote:
>
> fix f = f (fix f) -- Here you have your Y. No typeless lambda.
>
> g f n = n : f n-- This is a generic *non-recursive* `repeat`
> ones = fix g 1 -- Guess what.
>
>
Very nice! I honestly would not have expected this to work. Simple
cases of lazy eva
My simple-mindness and naïveté begin to bother me. I begin to get lost,
and I don't know anymore what is the problem...
Greg Woodhouse a écrit:
--- Paul Hudak <[EMAIL PROTECTED]> wrote:
...
The important property of Y is this:
Y f = f (Y f)
Right. This is just a formal statement of the pro
Greg Woodhouse wrote:
--- Paul Hudak <[EMAIL PROTECTED]> wrote:
The important property of Y is this:
Y f = f (Y f)
Right. This is just a formal statement of the property thaat f fixex Y
f. I'm with you so far.
In this way you can see it as "unwinding" the function, one step at a
time.
--- Paul Hudak <[EMAIL PROTECTED]> wrote:
>
> The important property of Y is this:
>
> Y f = f (Y f)
Right. This is just a formal statement of the property thaat f fixex Y
f. I'm with you so far.
>
> In this way you can see it as "unwinding" the function, one step at a
>
> time. If we defi
Greg Woodhouse wrote:
--- Paul Hudak <[EMAIL PROTECTED]> wrote:
Y (\ones. cons 1 ones)
where Y (aka the "paradoxical combinator" or "fixed point
combinator") is defined as:
\f. (\x. f (x x)) (\x. f (x x))
Now, this is I have seen, but it frankly strikes me as a "formal
trick". I've never fel
--- Paul Hudak <[EMAIL PROTECTED]> wrote:
>
> I suspect from your other post that you haven't seen the standard
> trick of encoding infinite data structures as fixpoints. Suppose you
> have a lambda calculus term for cons, as well as for the numeral 1.
> Then the infinite list of ones is just:
Greg Woodhouse wrote:
> --- Paul Hudak <[EMAIL PROTECTED]> wrote:
>>Tom Hawkins wrote:
>> > In a pure language, is it possible to detect cycles in recursive
>> > data structures? For example, is it possible to determine that
>> > "cyclic" has a loop? ...
>> >
>> > data Expr = Constant Int | Addit
Henning Thielemann wrote:
On Fri, 18 Nov 2005, Paul Hudak wrote:
For example:
fe1,fe2 :: Fix Expr
fe1 e = Add (Const 1) (Const 1) -- non-recursive
fe2 e = Add (Const 1) e -- recursive
Do you mean
fe1 _ = Add (Const 1) Loop
?
No, I really meant it as written. I included this examp
--- Paul Hudak <[EMAIL PROTECTED]> wrote:
> This is a very late response to an old thread...
>
> Tom Hawkins wrote:
> > In a pure language, is it possible to detect cycles in recursive
> > data structures? For example, is it possible to determine that
> > "cyclic" has a loop? ...
> >
> >
On Fri, 18 Nov 2005, Paul Hudak wrote:
For example:
fe1,fe2 :: Fix Expr
fe1 e = Add (Const 1) (Const 1) -- non-recursive
fe2 e = Add (Const 1) e -- recursive
Do you mean
fe1 _ = Add (Const 1) Loop
?
___
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Haskel
This is a very late response to an old thread...
Tom Hawkins wrote:
> In a pure language, is it possible to detect cycles in recursive
> data structures? For example, is it possible to determine that
> "cyclic" has a loop? ...
>
> data Expr = Constant Int | Addition Expr Expr
>
> cyclic :: Expr
Hello Tom,
Thursday, October 27, 2005, 6:46:41 PM, you wrote:
TH> In a pure language, is it possible to detect cycles in recursive data
TH> structures?
no, but it is possible in GHC. Einar Karttunen in his "SerTH - Binary
Serialization library for Haskell" used makeStableName and
unsafeCoerce#
On Thu, 27 Oct 2005, Lennart Augustsson <[EMAIL PROTECTED]> wrote:
> Tom Hawkins wrote:
>
>> Or phased differently, is it possible to make "Expr" an instance of
>> "Eq" such that cyclic == cyclic is smart enough to avoid a recursive
>> decent?
>
> No. And there is nothing that says that your defi
Hello,
On 10/27/05, Tom Hawkins <[EMAIL PROTECTED]> wrote:
> ...
> >> data Expr = Constant Int | Addition Expr Expr
> >>
> >> cyclic :: Expr
> >> cyclic = Addition (Constant 1) cyclic
> ...
> > And there is nothing that says that your definition of cyclic
> > will actually have a cycle in the imp
Tom Hawkins wrote:
Lennart Augustsson wrote:
Tom Hawkins wrote:
In a pure language, is it possible to detect cycles in recursive data
structures? For example, is it possible to determine that "cyclic"
has a loop? ...
data Expr = Constant Int | Addition Expr Expr
cyclic :: Expr
cyclic = A
Lennart Augustsson wrote:
Tom Hawkins wrote:
In a pure language, is it possible to detect cycles in recursive data
structures? For example, is it possible to determine that "cyclic"
has a loop? ...
data Expr = Constant Int | Addition Expr Expr
cyclic :: Expr
cyclic = Addition (Constant 1)
Tom Hawkins wrote:
In a pure language, is it possible to detect cycles in recursive data
structures? For example, is it possible to determine that "cyclic" has
a loop? ...
data Expr = Constant Int | Addition Expr Expr
cyclic :: Expr
cyclic = Addition (Constant 1) cyclic
Or phased different
In a pure language, is it possible to detect cycles in recursive data
structures? For example, is it possible to determine that "cyclic" has
a loop? ...
data Expr = Constant Int | Addition Expr Expr
cyclic :: Expr
cyclic = Addition (Constant 1) cyclic
Or phased differently, is it possible t
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