On Mon, Mar 19, 2007 at 03:22:29PM +, Simon Peyton-Jones wrote:
| This reminds me of something I discovered about using strict fields in
| AVL trees (with ghc). Using strict fields results in slower code than
| doing the `seq` desugaring by hand.
That is bad. Can you send a test case
On Mar 20, 2007, at 9:53 AM, Malcolm Wallace wrote:
Ian Lynagh [EMAIL PROTECTED] wrote:
data Fin a = FinCons a !(Fin a) | FinNil
w = let q = FinCons 3 q
in case q of
FinCons i _ - i
is w 3 or _|_?
Knowing that opinions seem to be heavily stacked against my
Malcolm wrote:
The Haskell Report's definition of `seq` does _not_ imply an order of
evaluation. Rather, it is a strictness annotation.
That is an important point.
Now, in the definition
x = x `seq` foo
one can also make the argument that, if the value of x (on the lhs of
the defn)
Simon Peyton-Jones wrote:
| strict fields have no effect on deconstructing data types.
That's GHC's behaviour too. I think it's the right one too! (It's
certainly easy to explain.)
This reminds me of something I discovered about using strict fields in
AVL trees (with ghc). Using strict
| This reminds me of something I discovered about using strict fields in
| AVL trees (with ghc). Using strict fields results in slower code than
| doing the `seq` desugaring by hand.
That is bad. Can you send a test case that demonstrates this behaviour?
| If I have..
|
| data AVL e = E
|
[EMAIL PROTECTED] writes:
Jón Fairbairn wrote:
[EMAIL PROTECTED] writes:
Besides, having
let q = FinCons 3 q in q
not being _|_ crucially depends on memoization.
Does it?
PS: Your derivations are fine in the case of a non-strict FinCons. But
the point is to make in
Hi all,
A while ago there was a discussion on haskell-cafe about the semantics
of strict bits in datatypes that never reached a conclusion; I've
checked with Malcolm and there is still disagreement about the right
answer. The original thread is around here:
http://www.haskell.org/pipermail
On Fri, Mar 16, 2007 at 05:40:17PM +0100, [EMAIL PROTECTED] wrote:
The translation
q = FinCons 3 q
=== (by Haskell 98 report 4.2.1/Strictness Flags/Translation
q = (FinCons $ 3) $! q
is rather subtle: the first FinCons is a strict constructor whereas the
second is the real
