On 9/24/10 10:01 PM, Gregory Crosswhite wrote:
Hey everyone,
There is something that has been bugging me recently about the
Applicative class and the Monad class.
Any type constructor F that is a Monad has a natural Applicative instance,
(<$>) :: F (a -> b) -> F a -> F b
mf <$> ma = do
f <- mf
>Have you given any thought as to how you want to approach versioning?
After giving this some more thought, I realized:
1) One of the "best practices" (even though I despise the term) of
versioning schema is to include a script with the code which checks
for each change to the tables, and makes th
On 9/25/10 3:43 PM, Jan-Willem Maessen wrote:
No one seems to have mentioned that this is a non-optimization in
call-by-need lambda-calculus (Ariola et al.), where it follows from
the standard reduction rules.
Exactly. Then again, call-by-need gives a form of partial evaluation,
which was what
On 9/24/10 5:35 AM, Axel Benz wrote:
Can anybody explain why this happens and how I can compose f and g?
Hint: It works fine if f is defined as an unary function.
As already mentioned: (g . f) x y = (\z-> g (f z)) x y = g (f x) y
In order to get it to work you need to say that you want to pas
Versioning is a tricky problem regardless of how you are creating
tables. And that isn't the problem I was aiming to tackle; the problem
I was aiming to tackle is a bit more narrow than that: I have a record
and now I need a table to stick it in.
By the way, how does HaskellDB handle versioning?
That sounds pretty awesome to me.
Have you given any thought as to how you want to approach versioning?
Maybe I'm asking a silly question - I have very little real world experience
with relation databases and how to version schemas.
Antoine
On Sep 25, 2010 2:31 PM, "Jonathan Geddes"
wrote:
> C
No one seems to have mentioned that this is a non-optimization in
call-by-need lambda-calculus (Ariola et al.), where it follows from
the standard reduction rules. Since lazy implementations of Haskell
all use call-by-need evaluation in some form, I'd call this "playing
by the rules" rather than "
Cafe,
HaskellDB takes a database schema and produces Haskell data structures
(plus some other query-related stuff for its EDSL query language).
What I'm looking for is the inverse of this functionality. I want to
create tables based on a Haskell data structure with a few simple
rules. These rules
JMacro on hackage: http://hackage.haskell.org/package/jmacro
This is the first official release announcement for JMacro, which has
been on hackage in some form for over a year, and in the current
version since July.
JMacro is a library for the programmatic generation of Javascript
code. It is des
On Sat, 25 Sep 2010, rgowka1 wrote:
I am trying to compile demo.hs, but keep getting the error that
Paths_gnuplot could not be found. What/where is paths_gnuplot?? Sorry,
I am still a beginner..
I forgot to mention in the documentation that you have to install with
$ cabal install -fbuildExam
On Sat, Sep 25, 2010 at 3:01 AM, Gregory Crosswhite
wrote:
> ==
>
> import Control.Applicative
> import Control.Concurrent
> import Control.Concurrent.MVar
>
> newtype AIO a = AIO {unAIO :: IO a}
>
> instance Monad AIO where
> r
On Sat, Sep 25, 2010 at 5:06 PM, Donn Cave wrote:
> Though it's common practice for sure, maybe universal, does the
> "Don't insert a space after a lambda" rule make sense?
>
> I found it confusing at first sight, because of course it looks
> like something else - in "\n m -> ...", to the uninitia
Though it's common practice for sure, maybe universal, does the
"Don't insert a space after a lambda" rule make sense?
I found it confusing at first sight, because of course it looks
like something else - in "\n m -> ...", to the uninitiated it
represents a newline, for example. Now that I unders
Am 25.09.2010 um 11:54 schrieb Tom Hawkins:
> Hi,
>
> Often I need to assemble a tree from things with unstructured
> hierarchical paths. I built a function [1] to do this for ImProve.
> But does a library already exist that does this? If not I may create
> one, as I need it for a few differen
I am trying to compile demo.hs, but keep getting the error that
Paths_gnuplot could not be found. What/where is paths_gnuplot?? Sorry,
I am still a beginner..
On Sat, Sep 25, 2010 at 8:48 AM, Henning Thielemann
wrote:
>
> On Sat, 25 Sep 2010, rgowka1 wrote:
>
>> Can I just do cabal install gnuplo
Hi,
I think what you need is a trie. See f.e.
http://hackage.haskell.org/package/list-tries
On Sep 25, 2010, at 11:54 AM, Tom Hawkins wrote:
> Hi,
>
> Often I need to assemble a tree from things with unstructured
> hierarchical paths. I built a function [1] to do this for ImProve.
> But does
On Sat, 25 Sep 2010, rgowka1 wrote:
Can I just do cabal install gnuplot or should I use darcs to get the
candles version..
The Hackage version should be up to date now.
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Can I just do cabal install gnuplot or should I use darcs to get the
candles version..
On Sat, Sep 25, 2010 at 8:03 AM, Henning Thielemann
wrote:
>
> On Sat, 25 Sep 2010, rgowka1 wrote:
>
>> Hi -
>>
>> What are the libraries to use in Haskell to generate a stock
>> candlestick chart like
>> http:
On Sat, 25 Sep 2010, rgowka1 wrote:
Hi -
What are the libraries to use in Haskell to generate a stock
candlestick chart like
http://stockcharts.com/h-sc/ui?s=SPY&p=D&b=5&g=5&id=p05007254056
I will use Finance-Quote-Yahoo to get the quote data from Yahoo.
You might try the gnuplot package as
Hi -
What are the libraries to use in Haskell to generate a stock
candlestick chart like
http://stockcharts.com/h-sc/ui?s=SPY&p=D&b=5&g=5&id=p05007254056
I will use Finance-Quote-Yahoo to get the quote data from Yahoo.
thanks for all your help.
___
Has
On Sat, Sep 25, 2010 at 11:24 AM, Petr Pudlak wrote:
> sometimes I have doubts how to structure my Haskell code - where to break
> lines, how much to indent, how to name functions and variables etc. Are
> there any suggested/recommended coding conventions? I searched a bit and I
> found a few arti
Hi,
Often I need to assemble a tree from things with unstructured
hierarchical paths. I built a function [1] to do this for ImProve.
But does a library already exist that does this? If not I may create
one, as I need it for a few different libraries.
data Tree a b = Branch a [Tree a b] | Leaf a
Hi,
sometimes I have doubts how to structure my Haskell code - where to
break lines, how much to indent, how to name functions and variables
etc. Are there any suggested/recommended coding conventions? I searched
a bit and I found a few articles and discussions:
- Good Haskell coding standar
On 25 September 2010 05:30, Evan Laforge wrote:
> I thought the parsec source included some example parsers for simple
> languages? In any case, there is lots of material floating around,
> [Snip]
The best documentation is Daan Leijen's original manual, plus the
original source distribution wh
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