, there is
no return for that in the Map case for exactly the same reason as with
Apply: the unit would have have value id for every possible key, so cannot
be finite.
So what about an example for Bind\\Monad that is not yet another variation
of the finite structure theme?
Cheers
--
Ben Franksen
Brent Yorgey wrote:
On Thu, Nov 29, 2012 at 03:52:58AM +0100, Ben Franksen wrote:
Tony Morris wrote:
As a side note, I think a direct superclass of Functor for Monad is not
a good idea, just sayin'
class Functor f where
fmap :: (a - b) - f a - f b
class Functor f = Apply f
.
GHC is just simply amazing. You guys RULE THE WORLD!
Cheers
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should hold
for them.
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implementations for
= in terms of = and vice versa, so that you can still use = as the
primitive operation when implementing an instance.
Cheers
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Alvaro Gutierrez wrote:
I've only dabbled in Haskell, so please excuse my ignorance: why isn't
there a 1-to-1 mapping between libraries and modules?
As I understand it, a library can provide any number of unrelated modules,
and conversely, a single module could be provided by more than one
Paolo Capriotti wrote:
On Mon, Apr 16, 2012 at 10:13 PM, Ben Franksen ben.frank...@online.de
wrote:
(1) What is the reason for the asymmetry in
type Producer b m = Pipe () b m
type Consumer a m = Pipe a Void m
i.e. why does Producer use () for the input? I would expect it to use
Void
Paolo Capriotti wrote:
I'm pleased to announce the release of version 0.1.0 of pipes-core, a
library for efficient, safe and compositional IO, similar in scope to
iteratee and conduits.
http://hackage.haskell.org/package/pipes-core
I like your pipes package. This is very similar to what
Magicloud Magiclouds wrote:
So I think I got what you guys meant, I limited ClassB to only H.
Then how to archive my requirement, that from and to only return items
that instanced ClassB?
If you are willing to go beyond Haskell98 (or Haskell2010), you can use a
multi-parameter class. Enable
You'll probably get answers from people who are more proficient with this,
but here's what I learned over the years.
Tim Baumgartner wrote:
Is Cont free as well?
No. In fact, free monads are quite a special case, many monads are not free,
e.g. the list monad. I believe what David Menendez
heathmatlock wrote:
Cute! I like it!
Yea, it's cute. I don't like the formula, though: \x - x + x is just too
trivial and not very Haskellish. Something higher order is the minimum
requirement, IMO. The original (lambda knights) formula was cool: the fixed
point operator is directly related
Benjamin Franksen wrote:
David Barbour wrote:
Create an extra TVar Int for every `chunk` in the array (e.g every 256
elements, tuned to your update patterns). Read-write it (increment it, be
sure to force evaluation) just before every time you write an element or
slice it or slice the array
I have an application in mind where concurrent access to large arrays (up to
millions of elements) of mostly small elements (Int or Double) is common.
Typical access patterns would be chunk-wise, i.e. reads or writes from index
n up to index m. Imagine stuff like images, scientific data, etc.
David Barbour wrote:
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
Ketil Malde wrote:
Ben Franksen ben.frank...@online.de writes:
An array of TVars is certainly *much* too inefficient for what I have in
mind w.r.t. both memory and cpu time.
You must be a lot more confident than I if you say this without
benchmarking first. :-)
Ok, not science
Derek Elkins wrote:
On Sun, Oct 17, 2010 at 6:49 AM, Miguel Mitrofanov
miguelim...@yandex.ru wrote:
On 17 Oct 2010, at 05:21, Ben Franksen wrote:
I want to prove that
f r == do
s1 - readIORef r
r' - newIORef s1
x - f r'
s3 - readIORef r'
writeIORef r s3
return x
That is not true
Ben Millwood wrote:
On Sun, Oct 17, 2010 at 11:15 AM, Malcolm Wallace
malcolm.wall...@me.com wrote:
The problem with the code you originally posted was that it looked like
this:
f r = do r' - something
f r'
something else -- this is dead code
That is, the computation is non-terminating,
Hi Mathew
Matthew Brecknell wrote:
Ben Franksen wrote:
Suppose we have a function
f :: IORef a - IO b
I want to prove that
f r == do
s1 - readIORef r
r' - newIORef s1
x - f r'
s3 - readIORef r'
writeIORef r s3
return x
I'm not sure where in your
Don Stewart wrote:
ben.franksen:
Haskell is an advanced purely functional programming language.
Good start, if only the advanced were replaced with something more
characteristic, like lazy, or statically typed. Which, BTW, both
do not
lazy and statically
Donn Cave wrote:
Quoth Ben Franksen ben.frank...@online.de,
Enough. I think I have made my point.
Yes, though possibly a little overstated it. While it's easy to share
your distaste for the blurb, if you take a generous attitude towards it,
most of it is true enough.
Sorry. I
Christopher Done wrote:
On 16 October 2010 05:52, Ben Franksen ben.frank...@online.de wrote:
what marketing idiot has written this inclonclusive mumble-jumble of
buzz-words?
[...]
How can anyone write such a
nonsense? Haskell is not an open source product!
[...]
I am ashamed
Ben Franksen wrote:
That cutting edge research is done for Haskell as well as for its
implementations is of course good to know, but just stating it is
not nearly enough: such a statement must be corroberated with
evidence, otherwise it is just idle marketing
I have a formal proof where I am stuck at a certain point.
Suppose we have a function
f :: IORef a - IO b
I want to prove that
f r == do
s1 - readIORef r
r' - newIORef s1
x - f r'
s3 - readIORef r'
writeIORef r s3
return x
What happens here is that the temporary
wren ng thornton wrote:
On 10/16/10 10:48 AM, Ben Franksen wrote:
Don Stewart wrote:
It is open source, and was born open source. It is the product of
research.
How can a language be open source, or rather, how can it *not* be open
source? The point of a (programming) language
wren ng thornton wrote:
On 10/16/10 11:22 AM, Ben Franksen wrote:
Much better. Though I *do* think mentioning the main implementations and
their qualities is a good thing to o, right after this:
[...]The most
important Haskell implementation, ghc [like to ghc page], has served as a
test bed
Derek Elkins wrote:
On Sat, Oct 16, 2010 at 9:21 PM, Ben Franksen ben.frank...@online.de
wrote:
I have a formal proof where I am stuck at a certain point.
Suppose we have a function
f :: IORef a - IO b
I want to prove that
f r == do
s1 - readIORef r
r' - newIORef s1
x - f r'
s3
This is a critique of the current 'Haskell Blurb', the first paragraph on
www.haskell.org.
This blurb should, IMO, give a concise description of what Haskell, the
programming language, is, what makes it different from other languages, and
why I should be interested in it.
What it does, instead,
Jason Dagit wrote:
On Tue, Oct 12, 2010 at 4:41 PM, Ben Franksen
ben.frank...@online.dewrote:
Seriously, the server is a debian etch (!) system. Also called debian
old-stable. Of course I have long since installed newer version of
darcs, but since I am not root there I cannot put it into /usr
One minor but important note: the hashed format is *not* readable with a
darcs-1 program:
(after a darcs optimize --upgrade
in /opt/repositories/controls/darcs/apps/HoBiCaT)
frank...@aragon:~/tmp /usr/bin/darcs --version
1.0.9rc1 (release candidate 1)
frank...@aragon:~/tmp /usr/bin/darcs
get
Neil Mitchell wrote:
This makes me curious. What's the use case where you want to allow the
user to pass arguments on the command line, but you don't want that user
to be able
to use '--help' to find out what arguments may be passed?
I wanted to create a clone of an existing program that had
Joachim Breitner wrote:
Am Dienstag, den 12.10.2010, 16:42 +1100 schrieb Ivan Lazar Miljenovic:
On 12 October 2010 16:32, Magnus Therning mag...@therning.org wrote:
This makes me curious. What's the use case where you want to allow the
user to pass arguments on the command line, but you
Roman Cheplyaka wrote:
On Mon, 11 Oct 2010 13:09:00 +0200, Vo Minh Thu not...@gmail.com wrote:
2010/10/11 Roman Cheplyaka r...@ro-che.info:
On Mon, 11 Oct 2010 11:54:12 +0100, Magnus Therning
mag...@therning.org
wrote:
On Mon, Oct 11, 2010 at 08:37, Michael Snoyman mich...@snoyman.com
Jason Dagit wrote:
On Tue, Oct 12, 2010 at 2:02 PM, Ben Franksen
ben.frank...@online.dewrote:
One minor but important note: the hashed format is *not* readable with a
darcs-1 program:
Sorry about that. The support for hashed repos existed long before 2.0
was released and so I
Stephen Tetley wrote:
On 10 October 2010 11:31, C K Kashyap ckkash...@gmail.com wrote:
Did you mean this
http://www.cs.tufts.edu/~nr/comp150fp/archive/richard-bird/sudoku.pdf?
I was actually meaning these slides...
http://icfp06.cs.uchicago.edu/bird-talk.pdf
But the paper is definitely
Florian Weimer wrote:
At least in my experience, in order to get proper resource management
for things like file or database handles, you need both a close
operation and a finalizer registered with the garbage collector. The
former is needed so that you can create resources faster than the
Florian Weimer wrote:
* Ben Franksen:
You might be interested in Lightweight Monadic Regions
http://okmij.org/ftp/Haskell/regions.html#light-weight
which solve the problem (IMHO) in a much cleaner way, i.e. w/o explicit
closing and also w/o using finalizers.
Is this approach
Thomas DuBuisson wrote:
On Fri, Oct 8, 2010 at 2:23 PM, Alex Rozenshteyn rpglove...@gmail.com
wrote:
Does there exist a library which allows me to have maps whose elements
are maps whose elements ... with a convenient syntax.
The containers library can do this already - there are no
Arie Peterson wrote:
On Sun, 03 Oct 2010 19:18:08 +0200, Ben Franksen
ben.frank...@online.de wrote:
How can I disable the standard arguments 'help' and 'version'?
If you're not fully committed to the cmdargs package, you might try my
package 'console-program' instead
http
Stephen Tetley wrote:
Does this one give the expected error message for Parsec3.1 -
unfortunately I can't test as I'm still using Parsec 2.1.0.1.
parser = block (many digit ? digit)
Unfortunately, no.
Cheers
Ben
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Henning Thielemann wrote:
On Sun, 3 Oct 2010, Ben Franksen wrote:
Christopher Done wrote:
Consider the following program:
main = putStrLn $ show $ length [undefined :: a,undefined :: b]
A concrete type of the element in list doesn't need to be determined
at runtime, or any time. a unifies
How can I disable the standard arguments 'help' and 'version'?
Cheers
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c8h10n4o2 wrote:
No, it is not secret. I'm having trouble to define functions. Take a look
at my code(please be gentle)
http://haskell.1045720.n5.nabble.com/file/n3100036/hai1.hs hai1.hs
Can you explain in a few words what the Func constructor should represent
why it has three arguments? I ask
c8h10n4o2 wrote:
The problem is there. A function in Hai would be function-name,
arg1,argn=body.
Func stores function name,arguments and body as Strings(I was thinking to
put Func String String String).
The parser func that I wrote so far try to parse a function definition,
not a function
Antoine Latter wrote:
On Sun, Oct 3, 2010 at 11:55 AM, Ben Franksen ben.frank...@online.de
wrote:
Stephen Tetley wrote:
Does this one give the expected error message for Parsec3.1 -
unfortunately I can't test as I'm still using Parsec 2.1.0.1.
parser = block (many digit ? digit
Ben Franksen wrote:
The type checker tells you that you are using the same Map with different
key types: at 52:17-19 the key has type [Hai], whereas at 47:16-18 it has
type Hai.
The latter is in your Func case:
s/latter/former/
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Christopher Done wrote:
On 1 October 2010 15:27, Henning Thielemann
lemm...@henning-thielemann.de wrote:
Given the following code, that is accepted by GHC:
data Exist = forall a. Exist a
exist :: Exist
exist = Exist undefined
What type has the 'undefined' ?
I think its type is `a'.
Christian Maeder wrote:
Am 29.09.2010 20:01, schrieb Daniel Fischer:
On Wednesday 29 September 2010 19:10:22, Ben Franksen wrote:
Note the last line mentions only '}'. I would rather like to see
expecting } or digit
since the parser could very well accept another digit here.
parsec2
I have a question about Parsec. The following program
import Control.Applicative ((*),(*))
import Text.Parsec
import Text.Parsec.Char
block p = char '{' * p * char '}'
parser = block (many digit)
main = parseTest parser {123a}
gives the output
parse error at (line 1, column 5):
Ben Franksen wrote:
import Control.Applicative ((*),(*))
import Text.Parsec
import Text.Parsec.Char
block p = char '{' * p * char '}'
parser = block (many digit)
main = parseTest parser {123a}
gives the output
parse error at (line 1, column 5):
unexpected a
expecting }
Note
Daniel Fischer wrote:
On Wednesday 29 September 2010 19:10:22, Ben Franksen wrote:
Note the last line mentions only '}'. I would rather like to see
expecting } or digit
since the parser could very well accept another digit here.
parsec2 did that, I don't know whether that change
Andrew Coppin wrote:
On 29/09/2010 07:33 PM, Steve Schafer wrote:
The issue isn't that there aren't a lot of Windows developers who have
an interest in Haskell+GUI development. The issue is that nearly every
Windows developer who looks into Haskell+GUI says, This stuff sucks,
and walks
Romain Demeyer wrote:
Imagine this scenario : we have a set of threads (the workers) that have
(each) a result to compute (purely). When finished, they try to save the
result in an shared inbox, using STM. If the inbox is full, the thread
waits until the inbox is empty.
A specific thread is
wren ng thornton wrote:
On 9/17/10 4:04 PM, Ben Franksen wrote:
wren ng thornton wrote:
Note that when compilers do CPS conversion, everything is
converted into let-binding and continuations (i.e., longjump/goto with
value passing). It's just dual to the everything-is-lambda world,
nothing
wren ng thornton wrote:
On 9/16/10 4:59 PM, Ben Franksen wrote:
even though we always have
(\x - e) y == let x = y in e
which means that let can be translated to lambda, the converse is not
true,
Not exactly. Note that when compilers do CPS conversion, everything is
converted
Román González wrote:
On Thu, Sep 16, 2010 at 2:12 PM, Ben Franksen
ben.frank...@online.dewrote:
Sjoerd Visscher wrote:
But StrictIncl can't be a pointed functor, only endofunctors can be
pointed.
Could someone tell me what exactly a pointed functor is? I googled but
did not find
wren ng thornton wrote:
On 9/13/10 6:22 AM, Michael Lazarev wrote:
Thanks for examples and pointers.
Since I came from Lisp, it never occurred to me that let and lambda
are different constructs in Haskell.
I thought that
let x = y in f
is really
(\x - f) y
It turns out that
Sjoerd Visscher wrote:
But StrictIncl can't be a pointed functor, only endofunctors can be
pointed.
Could someone tell me what exactly a pointed functor is? I googled but did
not find a definition.
Thanks
Ben
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David Leimbach wrote:
I find it's often the most practical chapter that I hit a lot during
writes and changes to my server process I have in Haskell in our control
system code :-)
Are you actually saying that you use Haskell for a control system server?
Thta would be very interesting to me.
Neil Brown wrote:
Primarily I want to see in FGL: documentation, documentation and more
documentation.
+1
Cheers
Ben
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And here are the numbers for record -lam:
b...@sarun[1]: .../rtems/rtems-4.9.0 darcs --version
2.3.1 (release)
b...@sarun[1]: .../rtems/rtems-4.9.0 time darcs record -lam'import release
4.9.0'
Finished recording patch 'import release 4.9.0'
darcs record -lam'import release 4.9.0' 143,33s user
Ben Franksen wrote:
The situation with record is similar.
I admit that the huge RTEMS tree with over 7000 changes between the two
releases is challenging. However, earlier releases can do it (though it
takes long, much longer than with, say, mercurial).
Just for comparison, here
Yves Parès wrote:
Just one last remark: when I moved all my OpenGL calls from the main
thread to an unbound thread. I thought it'd not work -- because I assumed
I would have to launch it in a bound thread -- and however it went
right...
You were just lucky the RTS accidentally delegated all
Hi All
This rc release is still notably slower on some operations than older
releases. My test case is a large project named RTEMS (a real-time OS),
that we wish to import into darcs (at work) to better track our own
additions and modifications.
To repeat, download two adjacent releases, e.g.
Ben Franksen wrote:
b...@sarun[1]: .../rtems/rtems-4.9.0 time darcs whatsnew -l
Well, it is still running after 18 minutes! Top reports something like
PID USER PR NI VIRT RES SHR S %CPU %MEMTIME+ COMMAND
5702 ben 20 0 1112m 933m 3628 R 92.2 28.3 18:26.08 darcs
Ben Franksen wrote:
b...@sarun[1]: .../rtems/rtems-4.9.0 /usr/local/bin/darcs --version
2.2.1 (release)
b...@sarun[1]: .../rtems/rtems-4.9.0 time /usr/local/bin/darcs whatsnew
-l
# ...long output elided...
/usr/local/bin/darcs whatsnew -l 381,45s user 6,34s system 92% cpu
7:00,90 total
Yves Parès wrote:
But there are two things that remain obscure:
First, there is my situation: int the main thread, I call to some C
functions binded through FFI. All of them are marked 'unsafe', except one,
which is internally supposed to make pauses with 'usleep'.
I then execute in another
Yves Parès wrote:
I've also discovered something interesting: when I link with the
'threaded' runtime, but let the program use only one core (with '+RTS
-N1'), the problem disappears. How comes?
The whole thing remains a mystery, because I think what I'm trying to do
is quite common...
Jochem Berndsen wrote:
András Mocsáry wrote:
*My concern*
is about predictable failure of sw written in Haskell.
To illustrate it let's see a Haskell pattern matching example:
And in Haskell pattern matching:
switch 1 = Unchecked
switch 2 = Checked
switch 3 = Unknown
Let's
Daniel Fischer wrote:
Am Montag 14 Dezember 2009 01:44:16 schrieb Richard O'Keefe:
Where is it written that aesthetic judgements are _entirely_ a
matter of personal preference?
I think you could find that written in many texts on aesthetic relativism.
Doesn't matter, though.
Of course,
John D. Earle wrote:
Although much work has apparently gone into providing support for
manipulation binary data I was unable to uncover a Haskell equivalent of
the C fgetc and fputc functions. The Haskell equivalents work with Unicode
character streams, not bytes words etcetera. I did find a
Ketil Malde wrote:
minh thu not...@gmail.com writes:
Why should your code be licensed under GPL?
I think your code is covered by whatever license you wish.
An aggregate work, on the other hand, would need to be covered by the
GPL, and all source code would have to be available under GPL
+1
Alberto G. Corona wrote:
Hi haskell cafe:
concerning Stable Names
http://www.haskell.org/ghc/docs/6.10.4/html/libraries/base/System-Mem-StableName.html
makeStableName :: a - IO (StableName a)
I Did not test fully my proposal, and I´m thinking aloud, Just to inpire
others and
Michael Snoyman wrote:
On Mon, Dec 7, 2009 at 9:53 PM, Henning Thielemann
lemm...@henning-thielemann.de wrote:
On Mon, 7 Dec 2009, Michael Snoyman wrote:
I also think that in an earlier mail I answered, that errors can leave
you with corrupt data, say invalid file handles, memory pointers,
Gregory Crosswhite wrote:
On Dec 4, 2009, at 11:02 AM, Ben Franksen wrote:
Gregory Crosswhite wrote:
I have posted Blueprint to Hackage so that people can see what I have
done and possibly play with it.
Very interesting, this. However, I could not build it. I get [...]
At the moment you need
Michael Snoyman wrote:
On Sun, Dec 6, 2009 at 12:55 AM, Henning Thielemann
lemm...@henning-thielemann.de wrote:
On Sun, 6 Dec 2009, Michael Snoyman wrote:
I think there are plenty of examples like web servers. A text editor
with
plugins? I
don't want to lose three hours worth of work
Gregory Crosswhite wrote:
I have posted Blueprint to Hackage so that people can see what I have done
and possibly play with it.
Very interesting, this. However, I could not build it. I get
b...@sarun[2]: ~/tmp cabal install blueprint
Resolving dependencies...
cabal: There is no installed
Hi Ryan,
first, to get this out of the way, you wrote:
Also, your definition of Function seems to have problems with
scoping; unless you intended to make a dynamically scoped language,
No, absolutely not! In fact, the whole exercise has been born out of
frustration with certain ad-hoc
Ben Franksen wrote:
Ok, it seems I have a version that does what I want. It is not very
elegant, I have to manually wrap/unwrap the ErrorT stuff just for the Val
case, but at least it seems to work. Here it goes:
eval (Var x) = Eval $ ErrorT $ do
env - get
v - case M.lookup x env
Ryan Ingram wrote:
The problem is that ErrorT makes any argument to mdo *much* more
strict, and therefore much more likely to loop.
This is because each action needs to know whether the previous action
was successful before it can continue.
Thanks, you are confirming what I suspected. I
Ben Franksen wrote:
My problem is that I still don't understand why this is so! I know of
course that pattern matching is strict, but I thought this should be ok
here, since I evaluate the declarations _before_ the body, so when
evaluation of the body demands the variable, it will be defined
Derek Elkins wrote:
On Wed, Nov 25, 2009 at 3:48 PM, Ben Franksen ben.frank...@online.de
What am I missing?
The problem is the liftM2 in the Let branch of eval. You are
executing the body while making the bindings, so you are trying to
look up x while you are still trying to bind it. One
Derek Elkins wrote:
The following code works fine for me, so it seems you are missing some
details that may help.
[...snip code...]
Thank you! Indeed I did simplify the code when writing the message --
because I thought that those other bits could not possibly be at
fault... ;-)
*trying out
Emil Axelsson wrote:
Henning Thielemann skrev:
On Fri, 6 Nov 2009, Emil Axelsson wrote:
Henning Thielemann skrev:
I'm trying to get realtime signal processing with Haskell for long. I
make progress, but slowly. Has Ericsson ever thought about using
Haskell itself for signal processing?
I am trying to write an interpreter for a very simple untyped functional
language. I have a problem with mutually recursive let expressions, for
which my interpreter loops :(
This is a code snippet from the eval function:
eval :: Expr - Eval Value
eval (Let decls body) = mdo
let
Johan Tibell wrote:
I just wanted to say that I'd be really happy to see haskell-mode in
code.haskell.org. I think it will make it easier for people to hack on
it.
Another option is http://patch-tag.com/
Cheers
Ben
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Joe Fredette wrote:
Really? How? That sounds very interesting, I've got a fair knowledge
of basic topology, I'd love to see an application
to programming...
Compactness is one of the most powerful concepts in mathematics, because on
the one hand it makes it possible to reduce many infinite
Joe Fredette wrote:
That has got to be the single awesomest thing I have ever seen ever...
I was dumbfounded, too, when I first read about this.
BTW, and completely off-topic: if you like this, you might have fun too with
Conor McBride's discovery that data types can be differentiated, and the
S. Doaitse Swierstra wrote:
This problem of dynamically transforming grammars and bulding parsers
out of it is addressed in:
@inproceedings{1411296,
author = {Viera, Marcos and Swierstra, S. Doaitse and Lempsink,
Eelco},
title = {Haskell, do you read me?: constructing and composing
mf-hcafe-15c311...@etc-network.de wrote:
On Sat, Oct 10, 2009 at 11:11:24PM +0200, Daniel Fischer wrote:
No, readFile reads the file lazily.
hm? oh, you are right, now that i fixed all the other problems in my
code readFile isn't a problem any more either... (-:
(but then how does it
Ben Franksen wrote:
Next thing I'll try is to transform such a grammar into an actual
parser...
Which I also managed to get working. However, this exposed yet another
problem I am not sure how to solve.
The problem manifests itself with non-left-factored rules like
Number ::= Digit Number
Patrick LeBoutillier wrote:
Could/should the Haskell Weekly News be posted to the beginners list as
well?
I normally don't follow haskell-cafe (too much traffic and generally above
my level I must admit...), but I like to follow what's going on in the
Haskell community.
I find reading the
Ben Franksen wrote:
Ben Franksen wrote:
Next thing I'll try is to transform such a grammar into an actual
parser...
Which I also managed to get working.
First, before all this talking to myself here is boring you to death, please
shout and I'll go away. Anyway, at least one person has
Robert Atkey wrote:
A deep embedding of a parsing DSL (really a context-sensitive grammar
DSL) would look something like the following. I think I saw something
like this in the Agda2 code somewhere, but I stumbled across it when I
was trying to work out what free applicative functors were.
Joe Fredette wrote:
A ring is an abelian group in addition, with the added operation (*)
being distributive over addition, and 0 annihilating under
multiplication. (*) is also associative. Rings don't necessarily need
_multiplicative_ id, only _additive_ id.
Yes, this is how I learned it in
Emil Axelsson wrote:
Ben Franksen skrev:
minh thu wrote:
2009/10/7 Günther Schmidt gue.schm...@web.de:
I've informally argued that a true DSL -- separate from a good API --
should have semantic characteristics of a language: binding forms,
control structures, abstraction, composition. Some
Daniel Fischer wrote:
Am Montag 05 Oktober 2009 16:29:02 schrieb Job Vranish:
In what way is it not a number?
If there's a natural[1] implementation of fromInteger, good.
If there isn't, *don't provide one*.
fromInteger _ = error Not sensible is better than doing something
strange.
[1]
Eugene Kirpichov wrote:
Or you can use an effect system (however that doesn't give you the
opportunity of overriding IO functions, but I think that providing
such an opportunity with the means you suggest (splitting IO into many
sub-monads) is not going to be usable in the large scale)
By
minh thu wrote:
2009/10/7 Günther Schmidt gue.schm...@web.de:
I've informally argued that a true DSL -- separate from a good API --
should have semantic characteristics of a language: binding forms,
control structures, abstraction, composition. Some have type systems.
That is one
Hong Yang wrote:
Good libraries are not enough for a language to go beyond mere existence.
There must exist good documents, i.e., good tutorials, good books, and
good explanations and examples in the libraries, etc, that are easy for
people to learn and use. In my humble opinion, Haskell has a
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