at 6:29 AM, Sebastian Fischer fisc...@nii.ac.jpwrote:
On Sun, Jan 22, 2012 at 5:25 PM, David Barbour dmbarb...@gmail.com
wrote:
The laws for monads only apply to actual values and combinators of the
monad algebra
You seem to argue that, even in a lazy language like Haskell,
equational laws
Space leaks, time leaks, resource leaks, subtle divergence issues when
filtering lists, etc.
On Mon, Jan 23, 2012 at 11:57 AM, Jake McArthur jake.mcart...@gmail.comwrote:
On Mon, Jan 23, 2012 at 10:45 AM, David Barbour dmbarb...@gmail.com
wrote:
the repeated failures of attempting to model
If you want a simple translation, use Word8 (from Data.Word) for the type
and use Data.Bits for operations on it just like in C++. This would offer
you storage efficiency (if stored as a strict field).
If you want idiomatic Haskell, constructor of the form:
data ObjectType = Object | Item |
, Jan 21, 2012 at 8:09 PM, David Barbour dmbarb...@gmail.com
wrote:
In any case, I think the monad identity concept messed up. The property:
return x = f = f x
Logically only has meaning when `=` applies to values in the domain.
`undefined` is not a value in the domain.
We can define
2012/1/22 MigMit miguelim...@yandex.ru
Отправлено с iPad
22.01.2012, в 20:25, David Barbour dmbarb...@gmail.com написал(а):
Attempting to shoehorn `undefined` into your reasoning about domain
algebras and models and monads is simply a mistake.
No. Using the complete semantics — which
Performing bit-mask operations is possible via the Data.Bits operations (on
elements of type Word8 or Word16, etc.). But I must say, it doesn't seem
very `natural` in Haskell, nor even in other languages. It crosses lines,
binding abstraction to representation in order to improve efficiency.
The
As noted, IO is not strict in the value x, only in the operation that
generates x. However, should you desire strictness in a generic way, it
would be trivial to model a transformer monad to provide it.
E.g.
data StrictT m a = StrictT (m a)
runStrictT :: StrictT m a - m a
runStrictT (StrictT
On Sat, Jan 21, 2012 at 10:08 AM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 10:01:00-0800]
As noted, IO is not strict in the value x, only in the operation that
generates x. However, should you desire strictness in a generic way, it
would
On Sat, Jan 21, 2012 at 10:51 AM, David Menendez d...@zednenem.com wrote:
The Eval monad has the property: return undefined = const e = e.
You can't write `const e` in the Eval monad.
From what I can tell, your proposed monads do not.
You can't write `const e` as my proposed monad,
meet monad laws - even in strict languages.
On Sat, Jan 21, 2012 at 11:02 AM, David Barbour dmbarb...@gmail.com wrote:
On Sat, Jan 21, 2012 at 10:51 AM, David Menendez d...@zednenem.comwrote:
The Eval monad has the property: return undefined = const e = e.
You can't write `const e
On Sat, Jan 21, 2012 at 11:08 AM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 11:02:40-0800]
On Sat, Jan 21, 2012 at 10:51 AM, David Menendez d...@zednenem.com
wrote:
The Eval monad has the property: return undefined = const e = e.
You
On Sat, Jan 21, 2012 at 11:22 AM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 11:09:43-0800]
Logically only has meaning when `=` applies to values in the domain.
`undefined` is not a value in the domain.
We can define monads - which meet monad laws
On Sat, Jan 21, 2012 at 2:24 PM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 12:18:09-0800]
`undefined` is not a value in any domain. It isn't a value at all. It's
certainly not part of my monad language or algebra. Up to the semantic
level
? Here you evaluate the result, and not the computation itself.
Wouldn't it be:
(StrictT op) = f = op ` seq` StrictT (op = \x - runStrictT (f x))
??
2012/1/21 David Barbour dmbarb...@gmail.com
On Sat, Jan 21, 2012 at 10:08 AM, Roman Cheplyaka r...@ro-che.infowrote:
* David Barbour dmbarb
I'd say use of asynchronous exceptions should be a last resort. Developers
should be encouraged to explicitly model any event notification system they
use.
Regards,
Dave
On Tue, Jan 17, 2012 at 1:42 AM, Simon Marlow marlo...@gmail.com wrote:
This is an interesting problem, I think I might
I favor a wait-free concurrency model based on the `vat` from E language.
Vats can be modeled very easily in Haskell, and in many other languages. I
currently use such a vat model for my Haskell projects. I describe aspects
of it at a few places:
*
Full beta-reduction is certainly not strict but also doesn't guarantee
terminate even where it is possible (i.e. it might indefinitely unfold a
value without making progress). I don't think there is much you can say
about non-strictness and termination.
Regards,
Dave
On Mon, Jan 9, 2012 at 3:01
This would make a good blog article...
2011/12/12 Ertugrul Söylemez e...@ertes.de
Hello fellows,
after a few discussions on IRC and via private mail I feel obligated to
point out that arrows and in particular AFRP do not force you to use an
imperative style in any way. You can use a style
I don't like the lamb at all.
But I like the idea of a language mascot. I really like Adam Chlipala's
spidurweb:
http://www.impredicative.com/ur/
Maybe a lambdacat can volunteer. ;-)
Regards,
Dave
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On Wed, Nov 23, 2011 at 2:53 PM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
On 24 November 2011 09:10, David Barbour dmbarb...@gmail.com wrote:
I don't like the lamb at all.
But I like the idea of a language mascot. I really like Adam Chlipala's
spidurweb:
That to me is more
Major error is in the line of code: `| otherwise = dfs' g y ( v : vis )`
You need something closer to:
let vsx = dfs' g x (x : vis) in
dfs' g v vsx
That is, first visit everything you can reach from x, then backtrack to add
anything else you can reach from v. This implementation will
On Thu, Nov 3, 2011 at 8:35 AM, Andreas Voellmy
andreas.voel...@gmail.comwrote:
I just read Kazu Yamamoto's article on a high performance web server in
the latest Monad.Reader, and I came across a statement that doesn't sound
correct to me. He says:
When a user thread issues a system call, a
On Thu, Nov 3, 2011 at 10:22 AM, David Barbour dmbarb...@gmail.com wrote:
It is correct in context. Mighttpd does not use the -Nx argument to create
multiple OS threads, instead uses a `prefork` model that creates separate
processes to balance user invocations. Using multiple processes instead
On Mon, Oct 31, 2011 at 5:33 PM, Ryan Ingram ryani.s...@gmail.com wrote:
For example, I would love to be able to use the arrow syntax to define
objects of this type:
data Circuit a b where
Const :: Bool - Circuit () Bool
Wire :: Circuit a a
Delay :: Circuit a a
And ::
Several of the Haskell web server frameworks (Yesod, HAppS, etc.) come with
persistence support.
I believe you're taking the wrong approach here, with respect to `modified
concurrently` and the like. What does it mean for a Data.List to be
'modified concurrently'? If you need concurrency, first
On Sun, Oct 30, 2011 at 6:20 PM, Ben Franksen ben.frank...@online.dewrote:
According to the original STM paper the implementation does an equality
test, albeit only for pointer equality.
It strikes me as bad form to depend on characteristics of `the
implementation`.
An incremented integer
MonadPlus is `or` semantics, as is Alternative. It does, indeed, reflect
the Applicative/Monad difference.
On Sat, Oct 29, 2011 at 8:02 PM, Gregory Crosswhite
gcrosswh...@gmail.comwrote:
Hey everyone,
What is the difference between MonadPlus and Alternative? In my mind, it
would make sense
Haskore - music generation
Yesod, Snap, or HAppS - quick web application
Diagrams - easy image composition, 2D
GPipe - functional composition of 3D graphics and shaders (similar to Conal
Elliott's Vertigo).
(cabal - easy installs, downloads, packaging)
On Fri, Oct 28, 2011 at 12:06 AM, Joosten,
On Thu, Oct 27, 2011 at 5:55 AM, Captain Freako capn.fre...@gmail.comwrote:
SF.hs:11:10: `' is not a (visible) method of class `Arrow'
Failed, modules loaded: none.
import Prelude hiding ((.),id)
import Control.Category
you'll also need to define `instance Category SF`, since that is a
On Thu, Oct 27, 2011 at 7:07 PM, Captain Freako capn.fre...@gmail.comwrote:
Thanks for the reply, David.
I tried implementing your suggestions, such that my code now looks like
this:
While Ross Patterson followed Hughes closely, it was recognized that
Category could be separated from Arrow.
On Tue, Oct 25, 2011 at 10:47 AM, Ben Franksen ben.frank...@online.dewrote:
The main question is: does the STM transaction actually see that I
changed
part of the underlying array, so that the transaction gets re-tried? Or do I
have to implement this manually, and if yes: how?
Create an
Is there any way to `query` a diagram, i.e. associate data with each pixel
for mouse clicks? Or are the composition rules mostly write-only?
On Sun, Oct 23, 2011 at 11:47 AM, Brent Yorgey byor...@seas.upenn.eduwrote:
I am pleased to announce the release of version 0.4 of diagrams, a
:
On Sun, Oct 23, 2011 at 11:06:19PM -0700, David Barbour wrote:
Is there any way to `query` a diagram, i.e. associate data with each
pixel
for mouse clicks?
Yes. Every diagram has an associated 'query function', which
associates a monoidal value to every point. By default it just
On Thu, Oct 20, 2011 at 5:19 AM, Captain Freako capn.fre...@gmail.comwrote:
Hi David,
I was referring to the `f' in the `runAuto' function, not the `liftAu'
function.
-db
Ah, I see. You quoted one thing and spoke of another, and I got all
confused. Keep in mind that functions are arrows
On Thu, Oct 20, 2011 at 10:38 AM, thomas burt thedwa...@gmail.com wrote:
Curiously, the times reported for outside are about 5-8 times as long.
What is the cost of putStrLn relative to performing `stuffToDo` a few
hundred times?
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On Wed, Oct 19, 2011 at 8:07 PM, Captain Freako capn.fre...@gmail.comwrote:
One more question on the `runAuto' code, John:
If I understand the code correctly, `f' is an arrow. Yet, we're using
it on the right side of `=' in a simple assignment. How are we getting
away with that?
Thanks,
On Fri, Oct 14, 2011 at 1:31 AM, Ertugrul Soeylemez e...@ertes.de wrote:
David Barbour dmbarb...@gmail.com wrote:
If you want first-class behaviors or behavior transformers, those will
need a different abstraction than 'nested' behaviors. Nested != First
Class. You'd have special
On Fri, Oct 14, 2011 at 3:07 AM, Ertugrul Soeylemez e...@ertes.de wrote:
It's not about the laws, it's about losing state.
I think you should not accumulate state; the abstraction gives me a fresh
arrow each instant, conceptually and pragmatically. But it would not be
difficult to create an
On Fri, Oct 14, 2011 at 7:27 AM, Alan Jeffrey ajeff...@bell-labs.comwrote:
On 10/13/2011 10:43 PM, David Barbour wrote:
On Thu, Oct 13, 2011 at 7:54 AM, Alan Jeffrey ajeff...@bell-labs.com
mailto:ajeff...@bell-labs.com** wrote:
The `problem` such as it exists: you will be unable to causally
On Thu, Oct 13, 2011 at 7:54 AM, Alan Jeffrey ajeff...@bell-labs.comwrote:
A function (f : Beh A - Beh B) is causal whenever it respects =t, i.e.
(forall t . a =t b = f a =t f b).
Yes. Function outputs only depend on the past values of the input function.
Your solutions for double and weird
On Mon, Oct 10, 2011 at 9:44 AM, kaffeepause73 kaffeepaus...@yahoo.dewrote:
First of all - thanks a lot for this package, graphviz is an awesome tool
and
having this interface library is really convenient. There a three point
where I could use some help:
1. when I try to create a label with
On Sun, Oct 9, 2011 at 7:57 PM, Captain Freako capn.fre...@gmail.comwrote:
21 applyFilter :: Filter e a - FilterState - a - (Either e a,
FilterState)
22 applyFilter f s x = runState (runEitherT (runFilter f)) s
I still don't understand how I'm supposed to feed the input, `x', into the
On Sat, Oct 8, 2011 at 4:28 PM, Captain Freako capn.fre...@gmail.comwrote:
17 newtype Filter e a = F {
* 18 runFilter :: EitherT e (State FilterState) a
** * 19 } deriving (Monad, MonadState FilterState)
it compiles, but I can't figure out how I'd feed the input to the filter,
in
Functional Reactive Programming can model this sort of 'change over time'
incremental computation, but I doubt you'd get a performance benefit from it
unless your operations are considerably more expensive than '+' on numbers.
Look into the 'Reactive' library, and Conal Elliott's paper on it
On Fri, Oct 7, 2011 at 3:17 AM, Heinrich Apfelmus apfel...@quantentunnel.de
wrote:
FRP is somewhat orthogonal to incremental computation because FRP is
focusing on expressiveness while incremental computation focuses on
performance. You can formulate some incremental algorithms in terms of
On Sun, Oct 2, 2011 at 6:04 AM, Du Xi sdiy...@sjtu.edu.cn wrote:
--Is it possible to get around this and write the expand function? Of
course, x and y may be of different types
Not as written, but try HList.
http://hackage.haskell.org/package/HList
On Sun, Oct 2, 2011 at 8:45 AM, Du Xi sdiy...@sjtu.edu.cn wrote:
Then again , in typeclass definition how can I express the type a-b
where a is the type parameter of the class and b is a type deduced from
the rules defined in each instance of the class, which varies on a
per-instance basis?
On Sat, Oct 1, 2011 at 4:54 AM, Fred Smith ilikequot...@katamail.comwrote:
do you know if there is another way either to compute the closure of a
function or to serialize it in order to send the computation to
another host?
You'll need to capture the functions as serializable data while it
On Wed, Sep 28, 2011 at 6:04 AM, Andreas Voellmy
andreas.voel...@gmail.comwrote:
Sure. I'm writing a server that serves a number of long-lived TCP
connections.
How many are you looking at?
(ROFLSCALEhttp://www.youtube.com/watch?v=majbJoD6fzo?)
And how much activity? Do you need real-time
Thank you for the clarification. I had read those papers, but I was under
the impression that it was something already part of GHC 7.
Regards,
Dave
On Thu, Sep 29, 2011 at 8:45 PM, austin seipp a...@hacks.yi.org wrote:
On Thu, Sep 29, 2011 at 3:14 PM, David Barbour dmbarb...@gmail.com
wrote
forgot to CC list.
-- Forwarded message --
From: David Barbour dmbarb...@gmail.com
Date: 2011/9/6
Subject: Re: [Haskell-cafe] Is there any way to parametrize a value update
using record syntax?
To: Poprádi Árpád popradi_ar...@freemail.hu
2011/9/6 Poprádi Árpád popradi_ar
2011/9/6 Erik Hesselink hessel...@gmail.com
You can use the fclabels package [1] for this. It makes record labels
first class, and also provides functions to update parts of a record
in the state monad [2].
That's pretty nifty. Thanks for mentioning it.
On Mon, Sep 5, 2011 at 3:15 PM, Erik de Castro Lopo mle...@mega-nerd.comwrote:
Can't this be mostly solved by putting all these configuration parameters
in a struct and then using implicit parameters:
Implicit parameters seem like a fair option. And propagating:
(?fooConf :: FooConf) =
In addition to fixing 'Float', you should define the 'Fractional' instance
for MathExpression. This would let you use:
let pi = 3.14 :: MathExpression
So your instance of Fractional would look like:
instance Num MathExpression where
(+) a b = Add a b
(*) a b = Multiply a b
(-) a b =
All you need to know about asynchronous exceptions is: *don't use
them!* They're
too difficult to reason about, in terms of failure modes and such. Use TVars
or MVars instead.
On Tue, Aug 9, 2011 at 1:40 PM, Edward Z. Yang ezy...@mit.edu wrote:
Hello all,
I was recently reading Asynchronous
On Fri, Jul 29, 2011 at 1:15 PM, Conal Elliott co...@conal.net wrote:
Is there a collection of laws associated with the Foldable class? Or for
Traversable? - Conal
Judging by the documentation in the source, I think all the laws are in
terms of 'toList'...
2011/7/26 Burak Ekici ekcbu...@hotmail.com
what has been changed after the encapsulation
of 'par' function by Eval monad?
If you asked to compare the parallelisation via monads
with non-monadic manner of it, what could you say?
'Eval' provides some useful discipline and structure. It
2011/7/22 Александр kommunist1...@mail.ru
How can i make Monad type class instance for this tree? And can i make it
on not?
You'll apply 'f' to every node in the tree. You'll need some sensible
mechanism to merge the resulting trees.
You might have an easier time for merging a slightly
I have spent several months studying use of generative grammars in
multi-agent reactive systems [1] - granted, not FRP in particular, but RDP
is reasonably close [2]. This result is, implicitly, a distributed,
federated machine-learning system (briefly described at [3]). The 'learning'
supports
I'm a bit curious about who might be using GPipe.
I've been trying to find a good variation on OpenGL that integrates nicely
with reactive programming. Issues such as texture management seem to be
rather difficult targets.
On Sat, Jul 23, 2011 at 12:06 PM, Jake McArthur
Any relationship to distributed haskell?
http://www.macs.hw.ac.uk/~dsg/gdh/
On Fri, Jul 22, 2011 at 3:00 AM, Pasqualino Titto Assini
tittoass...@gmail.com wrote:
Fellow Haskeller,
Has your strongly typed, quick checked, formally verified, Oleg blessed,
higher order monadic code become a
On Tue, Jul 19, 2011 at 11:14 PM, yi huang yi.codepla...@gmail.com wrote:
2011/7/20 Eugene Kirpichov ekirpic...@gmail.com
reallyUnsafePointerEq#, and it really is as unsafe as it sounds :)
Why is it so unsafe? i can't find any documentation on it.
I think always compare pointer first is a
On Wed, Jul 20, 2011 at 10:40 AM, Chris Smith cdsm...@gmail.com wrote:
I have looked up crowbar in a number of dictionaries of slang and
informal usage... and still have no idea what you just said. Can you
reword it?
Crowbars offer 'leverage'.
The point, I think, is that if pointer
On Tue, Jul 12, 2011 at 2:58 AM, Simon Marlow marlo...@gmail.com wrote:
I discovered the real reason we run statements in a separate thread: the
GHCi debugger. If the computation stops at a breakpoint, then we have to
save the context and resume GHCi, which can only be done if the computation
On Tue, Jul 12, 2011 at 6:55 PM, Felipe Almeida Lessa
felipe.le...@gmail.com wrote:
ArrowChoice's (+++) documentation [1] says that this is in general
not a functor [1]. What does it mean for (+++) to be or not to be a
functor?
The same note is made for (***). If you review Ross
2011/7/10 José Romildo Malaquias j.romi...@gmail.com
On Wed, Jul 06, 2011 at 02:48:47PM -0700, David Barbour wrote:
You could try the SDL package to support user input.
Unfortunatly it does not run on a terminal.
http://www.gamedev.net/topic/340894-how-do-i-keep-sdl-from-outputting-stdout
On Sat, Jul 9, 2011 at 3:58 AM, Henning Thielemann
lemm...@henning-thielemann.de wrote:
My stream processors are not Arrows, because 'first' cannot be implemented.
However, 'arr' and '.' can be implemented.
Currently I have build the two tasks into one stream processor. I would
like to
On Thu, Jul 7, 2011 at 11:08 PM, Heinrich Apfelmus
apfel...@quantentunnel.de wrote:
Can GUI programming be liberated from the IO monad?
I believe it can be. But is FRP the right way to achieve this? Most of the
GUI problems I've ever encountered involve open systems: configuration
files,
On Tue, Jul 5, 2011 at 9:00 PM, steffen steffen.sier...@googlemail.comwrote:
The important point about reference counting on idevices is the near
realtime performance, since stops for collecting garbage are actually very
short in comparison to collecting compilers (despite more frequent).
On Wed, Jul 6, 2011 at 8:09 AM, Simon Marlow marlo...@gmail.com wrote:
On 06/07/2011 15:42, Jason Dagit wrote:
How can I make sure my library works from GHC (with arbitrary
user threads) and from GHCI?
Right, but usually the way this is implemented is with some cooperation from
the main
On Wed, Jul 6, 2011 at 6:04 AM, Markus Läll markus.l...@gmail.com wrote:
Is it possible to define an Arrow instance of list to list functions?
import Control.Arrow
import Control.Category
type X a b = [a] - [b]
You need a newtype here. (-) is already an arrow.
On Wed, Jul 6, 2011 at 12:52 PM, Simon Marlow marlo...@gmail.com wrote:
I think the real issue is that GHC has a different behavior than GHCi,
and I think this causes a lot of difficulties for people working on GUI
and other FFI integration.
Well, GHCi has no main, so it doesn't seem
You could try the SDL package to support user input.
2011/7/6 José Romildo Malaquias j.romi...@gmail.com
Hello.
I want to write a Haskell console application (a game) in ghc where the
user will interact using the keyboard. I need to read the keys as soon
as they are typed and without
On Jul 3, 2011, Jason Dagit dag...@gmail.com wrote:
to correctly handle GUI events you need to use the original thread
allocated to your process to check for events and to call the Cocoa
framework functionality.
I looked at the threading documentation in Control.Concurrent for GHC and
it's
On Wed, Jun 22, 2011 at 1:25 PM, pipoca eliyahu.ben.mi...@gmail.com wrote:
Is there any reason why we don't have either anonymous disjoint union
types, or why some of the proposals here (e.g. type (:|:) a b = Either
a b ) haven't been implemented, or put into the standard libraries
(and
On Tue, Jun 21, 2011 at 3:18 AM, Richard Senington sc06...@leeds.ac.ukwrote:
I have been looking through the papers by Conal Elliott and Paul Hudak,
Hudak's book The Haskell School of Expression (chapters 13,15,17) and
the latest version of the Reactive library on Hackage.
In the past I
On Tue, Jun 21, 2011 at 1:36 PM, Matthew Steele mdste...@alum.mit.eduwrote:
Yes, Either is to sum types what (,) is to product types. The difference
is that there is no anonymous sum type equivalent to (,,) and (,,,) and
() and so on, which I think is what the original question is getting
On Tue, Jun 21, 2011 at 2:24 PM, pipoca eliyahu.ben.mi...@gmail.com wrote:
On Jun 21, 4:57 pm, Alexey Khudyakov alexey.sklad...@gmail.com
wrote:
Types may be same.
oops :: Int :+: Int - Int
oops Int i = mmm which one?
If you were to have your anonymous sum types be a union instead of
] http://awelonblue.wordpress.com/2011/05/21/comparing-frp-to-rdp/
Regards,
David Barbour
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On Mon, Jun 20, 2011 at 1:33 AM, Dmitri O.Kondratiev doko...@gmail.comwrote:
Thanks! Everything works, and 'when' is really nice.
( I still have only basic monad knowledge, need more time to spend on
existing libraries)
I heavily use 'when' and 'unless'. ('unless b x' is the same as 'when
Look into Oleg's HList (heterogeneous list) and OOHaskell
http://homepages.cwi.nl/~ralf/HList/
http://homepages.cwi.nl/~ralf/OOHaskell/
On Thu, Jun 16, 2011 at 5:08 AM, kaffeepause73 kaffeepaus...@yahoo.dewrote:
Dear all,
I'm created a timeSignal datatype as container around a Vector Double
On Sun, Jun 5, 2011 at 12:51 PM, KC kc1...@gmail.com wrote:
If new intermediate classes crop up then there would be no point in fixing
class (Applicative m) = Monad m where
since it would have to be changed if new intermediate classes are found.
You might check out a few articles regarding
On Mon, Jun 6, 2011 at 4:05 PM, Casey McCann syntaxgli...@gmail.com wrote:
ArrowChoice and ArrowApply are conceptually distinct and I expect
there are instances of the former that have no possible instance for
the latter. Branching vs. Monad I am much less certain of.
For a real-time or
On Tue, Jun 7, 2011 at 6:14 AM, Casey McCann syntaxgli...@gmail.com wrote:
On Mon, Jun 6, 2011 at 7:55 PM, David Barbour dmbarb...@gmail.com wrote:
Earlier forms of my reactive demand programming model [1] - before I
switched to arrows - would qualify. The model has limited side-effects
[Apparently I forgot to hit reply-all.]
Thanks for your response, Adam.
On Tue, May 10, 2011 at 1:25 PM, Adam Megacz meg...@cs.berkeley.edu wrote:
class (GArrowMap a (**) u c) = GArrowJoin a (**) u c where
join :: a d (c r) - a (c d) (c r)
I like these; I think you're on the right
I wonder if I need something like your use of 'representation' types, i.e.
to restrict what sort of elements can be stored in a collection.
I've just recently hit on the idea of using a barrier type 'V' to wrap a
synchronous value. A 'synchronous value' is one that can be observed at a
single
Has anyone developed a typeclass model for (Control.Monad.mapM) and related
functions for arrows?
I've a preliminary model, using Adam Megacz's Generalized Arrows, of the
form:
class (GArrowDrop a (**) u) = GArrowMap_ a (**) u c where
mapA_ :: a d u - a (c d) u
class (GArrow a (**) u c) =
I was giving Control.Arrow a try for a reactive programming system.
The arrows are agents that communicate by sending and returning
time-varying state. Different agents may live in different 'vats'
(event-driven threads) to roughly model distributed computing. For the
most part, the state varies
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