On Thu 07 Oct, Manuel M. T. Chakravarty wrote:
Check out the type signatures of the `MVar'-related
operations and you will find that they are all nicely
encapsulated in the `IO' monad.
This is true, but I think the point of contention is does the IO monad
itself provide referential
On Thu 07 Oct, Marcin 'Qrczak' Kowalczyk wrote:
In Haskell a `variable' can be meant to be either a name introduced
by a let/where/lambda/case binding, or one of IORef/STRef/MVar (or
even something in a custom monad). The first concept is referentially
transparent, the second is not if we
On Thu 07 Oct, Jan Skibinski wrote:
I think that the monadic IO provides us with such a
simplification. As long as we realize what are its limitations
and as long as we stay within reasonable limits of the concept
we should be fine here. The operative word here is "realize".
Do we really
On Thu 07 Oct, I wrote:
On Wed 06 Oct, Johan Nordlander wrote:
Just to avoid any unfortunate misconceptions: O'Haskell definitely
preserves the property we commonly refer to as referential transparency,
and so does Concurrent Haskell, or any other sound monadic extension of
the language.
On 07-Oct-1999, Adrian Hey [EMAIL PROTECTED] wrote:
On Thu 07 Oct, Michael Hobbs wrote:
Michael Hobbs wrote:
Consider this:
type IO a = StateOfUniverse - (a, StateOfUniverse)
-- Not syntactically correct, but you know what I mean.
So anything that is declared, say `IO
On 08-Oct-1999, Adrian Hey [EMAIL PROTECTED] wrote:
Reaction to my recent suggestion regarding IO (a concurrent non-deterministic
machine) on the Clean discussion list was somewhat less than enthusiastic.
One of the reasons was that apparently this would result in loss of
referential
Hi,
As far as I understood the matter, referential transparency
denotes the property of a language, in which variables of the
same scope do not change their value.
Given
let var = some unmonadic expression
...
... -- some calculation
some monadic expression
...
Hello again Fergus,
For some reason you have sent this message to me despite the fact that
all the words you appear to disagree with are those of Michael Hobbs:-)
However, I assume you also disagree with my words so I'll try to respond.
Unfortunately we've been over this ground before on
| As far as I understood the matter, referential transparency
| denotes the property of a language, in which variables of the
| same scope do not change their value.
So ML and Erlang are referentially transparent too?
Doesn't referential transparency include something about
functions
On Thu, 7 Oct 1999, Adrian Hey wrote:
On Thu 07 Oct, Manuel M. T. Chakravarty wrote:
Check out the type signatures of the `MVar'-related
operations and you will find that they are all nicely
encapsulated in the `IO' monad.
This is true, but I think the point of contention is does the
On 07-Oct-1999, Adrian Hey [EMAIL PROTECTED] wrote:
This is another reason I'm sceptical about referential transparency in
any functional system of IO (streams, monads, continuations, world as value..)
It is hard to sensibly define interaction between a timeless universe
of pure functions and
On 08-Oct-1999, Adrian Hey [EMAIL PROTECTED] wrote:
I think it's important
to understand whether or not we really do have referential transparency
with monadic IO, if other models of interaction between program and
outside world are (like those in Concurrent Haskell) going to be rejected
Folks,
Traffic on the Haskell mailing list has jumped dramatically of late.
In many ways that's a good thing: I take it a symptomatic that Haskell is
getting used for more things by more people.
But it has a bad side: if traffic is too heavy, large numbers of people will
unsubscribe (indeed,
| As far as I understood the matter, referential transparency
| denotes the property of a language, in which variables of the
| same scope do not change their value.
So ML and Erlang are referentially transparent too?
Before everybody gets completely muddled up,
I point to a
So we can decide to do one of two things:
1. Try to keep the Haskell mailing list as a low-traffic list, to which
many, many people subscribe. Under this model, one might *start*
a discussion on the Haskell list; but after a few exchanges, move the
discussion to
Traffic on the Haskell mailing list has jumped dramatically of late.
[...]
So we can decide to do one of two things:
1. Try to keep the Haskell mailing list as a low-traffic list, to which
many, many people subscribe. Under this model, one might *start*
a discussion on the Haskell
On Thu 07 Oct, Michael Hobbs wrote:
Michael Hobbs wrote:
Consider this:
type IO a = StateOfUniverse - (a, StateOfUniverse)
-- Not syntactically correct, but you know what I mean.
So anything that is declared, say `IO Int', means that it is actually a
function that reads in
Perhaps we should create a comp.lang.haskell? -Paul
On Fri 08 Oct, Wolfgang Lohmann wrote:
Monadic IO is not thought ( in my opinion) to have IO during
_the whole_ program, while preserving the referential transparency.
Monads are fine to encapsulate effects, and so the IO Monad
encapsulates input/output effects _to preserve_ the referential
S.J.Thompson writes:
I agree with Simon's observations, and would suggest a third option: why not
set up comp.lang.haskell?
I agree with the above.
The established procedure for creation of a news group is documented in the
news.announce.newgroups FAQ available at:
[EMAIL
Colin Runciman [EMAIL PROTECTED] wrote:
I also agree with Simon that simply making this a moderated list is
not the solution. Perhaps splitting is best. How about
haskell-info
haskell-talk
where info carries *brief* announcements, requests for information
and responses to such
Simon PJ is too valuable to lose. I
(a) second the creation of comp.lang.haskell;
(b) suggest that [EMAIL PROTECTED] should have a policy
(enforced mechanically if necessary) of 1 contribution of length
at most 5 lines (or 350 characters) per user per thread.
"Manuel" == Manuel M T Chakravarty [EMAIL PROTECTED] writes:
[...]
Manuel What do you think?
I'll use the opportunity to advocate wiki usage.
While I agree that it seems time to have multiple lists, some of the
recent high volume threads could have used the wiki to collect,
discuss and then
On Fri, 8 Oct 1999 [EMAIL PROTECTED] wrote:
Some time ago there was a discussion about what to call reverse
composition (I can't find it in the archive - needs a search option?)
Just now I thought of .~ from . for composition and ~ (tilde, but
commonly called twiddle) for twiddling the
Some time ago there was a discussion about what to call reverse
composition (I can't find it in the archive - needs a search option?)
Just now I thought of .~ from . for composition and ~ (tilde, but
commonly called twiddle) for twiddling the order about.
Maybe we could adopt that as normal
[EMAIL PROTECTED] wrote:
set up comp.lang.haskell?
I agree with the above.
This is IMHO the best solution for a lot of reasons:
1. With many providers/client_softwares, you cannot ignore
a mail without downloading and deleting it. This makes it
hard to ignore a thread which one is not
On Fri, 8 Oct 1999, Hamilton Richards Jr. wrote:
At 1:01 PM -0500 10/8/1999, [EMAIL PROTECTED] wrote:
Some time ago there was a discussion about what to call reverse
composition (I can't find it in the archive - needs a search option?)
Just now I thought of .~ from . for composition and
[EMAIL PROTECTED] wrote:
Some time ago there was a discussion about what to call reverse
composition (I can't find it in the archive - needs a search option?)
Just now I thought of .~ from . for composition and ~ (tilde, but
commonly called twiddle) for twiddling the order about.
Maybe
Personal taste in infix operators seems to be another good argument for a
camlp4-style preprocessor for Haskell. For instance I would like to use
'o' for composition (since anybody who uses 'o' for a variable gets what
they deserve!) but I guess that would make the lexer not so nice.
I would
On 8 Oct, Christopher Jeris wrote:
Personal taste in infix operators seems to be another good argument for a
camlp4-style preprocessor for Haskell.
Please no! I want to be able to read other folks programmes and vice
versa. The whole point of suggesting a particular glyph on this foram
Fri, 8 Oct 1999 19:01:07 +0100 (BST), [EMAIL PROTECTED]
[EMAIL PROTECTED] pisze:
Some time ago there was a discussion about what to call reverse
composition (I can't find it in the archive - needs a search option?)
Just now I thought of .~ from . for composition and ~ (tilde,
but commonly
On Fri 08 Oct, Lars Lundgren wrote:
A value (IO a) *denotes* a program possibly interacting with the world.
*That* program is of course not referentially transparent. A haskell
program generating an (IO a) on the other hand *is* referetially
transparent.
So a value of type (IO a) is _not_ a
On 8 Oct, Jonathan King wrote:
I think you might see the point. (No pun back there, I promise...) I
understand where using "." to mean composition came from, and I know that
it's a long-standing tradition in at least the Haskell community, but I
don't think the visual correspondence of
At 1:01 PM -0500 10/8/1999, [EMAIL PROTECTED] wrote:
Some time ago there was a discussion about what to call reverse
composition (I can't find it in the archive - needs a search option?)
Just now I thought of .~ from . for composition and ~ (tilde, but
commonly called twiddle) for twiddling the
| What progress on the Great Hugs Collaboration? That is,
| being able to run
| Hugs bytecode inside GHC or GHC compiled code inside Hugs. I
| don't expect much detail but if the marriage is expected Real Soon Now, or
| alternatively has been postponed indefinitely, I would like to know!
An
Thu, 07 Oct 1999 19:13:34 -0400, Kevin Atkinson [EMAIL PROTECTED] pisze:
One think I really think it needs is the ability to group a
collection of functions with a tag. And then when importing a
module you can ask to only import that tag. For example:
module A
list: head tail foldr
On 8 Oct, Joe English wrote:
[I wrote]:
Just now I thought of .~ from . for composition and ~ (tilde, but
commonly called twiddle) for twiddling the order about.
I've also seen .| and |. used for this purpose (by
analogy with Unix pipes.)
John Hughes' Arrow library spells it "",
"Manuel M. T. Chakravarty" wrote:
Some bits pieces:
* After playing around with this module, I think that it is a
Good Thing (tm) that ...OffAddr use element offsets and not
byte offsets. It makes instance declarations of the following
form much easier:
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