Re: [Haskell-cafe] Word8 literals in ByteString haddock?
At Wed, 27 Mar 2013 00:50:21 +, Niklas Hambüchen wrote: Hey, according to http://hackage.haskell.org/packages/archive/bytestring/0.10.2.0/doc/html/Data-ByteString.html#v:split I can write: split '\n' a\nb\nd\ne Can I really do that? I don't know of a way to make a '\n' literal be a Word8, so maybe these Haddocks are wrong? I guess they would apply for Data.ByteString.Char8, but this is Data.ByteString. Or is there a way? No, there is no way—you’d need an ‘OverloadedChars’ extension that does not exist. I think that text is meant to show the semantics of ‘split’ rather than being actual code. Francesco ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] my take at knucleotide
I have posted this version.Mad home grown HashMap and replaced IOref with
Ptr.This made program twice as fast as current entry.
{-# Language BangPatterns #-} The Computer Language Benchmarks Game--
http://benchmarksgame.alioth.debian.org/ Contributed by Branimir
Maksimovic--import Data.Bitsimport Data.Charimport Data.Intimport
Data.Listimport Data.Array.Baseimport Data.Array.Unboxedimport
Data.Array.IOimport qualified Data.ByteString.Char8 as Simport
Foreign.Ptrimport Foreign.Storableimport Foreign.Marshal.Allocimport
Control.Concurrentimport Text.Printf
main = dolet skip = dol - S.getLineif S.isPrefixOf
(S.pack THREE) lthen return ()else skip
skips - S.getContentslet content = S.filter ((/=) '\n') s;mapM_
(execute content) actionsdata Actions = I Int | S Stringactions = [I 1,I 2,
S GGT,S GGTA,S GGTATT,S GGTAAATT,S
GGTAAATTTATAGT]execute content (I i) = writeFrequencies content iexecute
content (S s) = writeCount content s
writeFrequencies :: S.ByteString - Int - IO ()writeFrequencies input size =
doht - tcalculate input sizelst - Main.foldM (\lst (k,v)-do
v' - peek vreturn $ (k,v'):lst) [] htlet sorted = sortBy (\(_,x)
(_,y) - y `compare` x) lstsum = fromIntegral ((S.length input) + 1 -
size)mapM_ (\(k,v)- doprintf %s %.3f\n (toString k)
((100 * (fromIntegral v)/sum)::Double)) sortedputChar '\n'
writeCount :: S.ByteString - String - IO ()writeCount input string = do
let size = length stringk = T (toNum (S.pack string) 0 size) sizeht
- tcalculate input sizeres - Main.lookup ht kcase res of
Nothing - putStrLn $ string ++ not found...Just v - do
r - peek vprintf %d\t%s\n r string
tcalculate :: S.ByteString - Int - IO HMtcalculate input size = dolet
l = [0..63]actions = map (\i - (calculate input i size (length
l))) lvars - mapM (\action - dovar - newEmptyMVar
forkIO $ doanswer - action
putMVar var answerreturn var) actionsresult
- newTable :: IO HMresults - mapM takeMVar varsmapM_ (\ht -
Main.foldM (\lst (k,v) - do res - Main.lookup lst
kcase res ofNothing
- dor1 - peek v
r2 - mallocpoke r2 r1
Main.insert lst k r2Just
v1 - dor1 - peek v1
r2 - peek vpoke v1 (r1+r2)
return lst) result ht) resultsreturn result
calculate :: S.ByteString - Int - Int - Int - IO HMcalculate input beg
size incr = do!ht - newTable :: IO HMletcalculate' i
| i = ((S.length input)+1 - size) = return ht | otherwise = do
let k = T (toNum input i size) sizeres - Main.lookup ht k
case res ofNothing - do!r - malloc
poke r 1Main.insert ht k r
Just v - do !r - peek vpoke v (r+1)
calculate' (i+incr)calculate' beg
toNum :: S.ByteString - Int - Int - Int64toNum s beg size = toNum' 0 size
wheretoNum' v 0 = vtoNum' v i = toNum' ((v `shiftL` 2) .|.
(toNumA `unsafeAt` (ord (S.index s (beg+i-1) (i-1)
toString :: T - StringtoString (T v s) = toString' v swhere
toString' v 0 = []toString' v i = case v..3 of
0 - 'A'1 - 'C'2 - 'T'
3 - 'G' : toString' (v `shiftR` 2) (i-1)
toNumA :: UArray Int Int64toNumA = array (0,255) [(ord 'a',0),(ord 'c',1),(ord
't',2),(ord 'g',3),(ord 'A',0),(ord 'C',1),(ord 'T',2),(ord 'G',3)]
data T = T !Int64 !Intinstance Eq T where(T a _) == (T b _) = a == bclass
Hash h wherehash :: h - Int64instance Hash T wherehash (T a _) = a
type HM = HashMap T (Ptr Int)data HashMap k v = HashMap !(IOArray Int64
[(k,v)])tsz = 4096newTable :: IO (HashMap k v)newTable = do!array -
newArray (0,(tsz-1)) []return $ HashMap array
lookup :: (Eq k, Hash k)=HashMap k v - k - IO (Maybe v)lookup (HashMap a) k
= dolet h = hash k!lst - readArray a (h .. (tsz-1))let
loop [] = return Nothingloop ((!k',!v):xs) | k /= k' = loop
xs| otherwise = return $ Just vloop lst
insert :: (Eq k, Hash k)=HashMap k v - k - v - IO ()insert (HashMap a) k v
= dolet h = hash k!lst -
Re: [Haskell-cafe] Pattern matching with singletons
Very helpful, thanks! I may come back with more singleton/type families
questions :)
On Tue, Mar 26, 2013 at 6:41 PM, Richard Eisenberg e...@cis.upenn.eduwrote:
Hello Paul,
- Forwarded message from Paul Brauner polux2...@gmail.com -
snip
- is a ~ ('CC ('Left 'CA)) a consequence of the definitions of SCC,
SLeft, ... (in which case GHC could infer it but for some reason can't)
- or are these pattern + definitions not sufficient to prove that a
~ ('CC ('Left 'CA)) no matter what?
The first one. GHC can deduce that (a ~ ('CC ('Left b))), for some fresh
variable (b :: TA), but it can't yet take the next step and decide that,
because TA has only one constructor, b must in fact be 'CA. In type-theory
lingo, this deduction is called eta-expansion. There have been on-and-off
debates about how best to add this sort of eta-expansion into GHC, but all
seem to agree that it's not totally straightforward. For example, see GHC
bug #7259. There's a non-negligible chance I will be taking a closer look
into this at some point, but not for a few months, so don't hold your
breath. I'm not aware of anyone else currently focusing on this problem
either, I'm afraid.
I'm glad you're finding use in the singletons package! Let me know if I
can be of further help.
Richard
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[Haskell-cafe] [extension]syntactic sugar for maps
Hi, I am terribly missing some syntactic sugar for maps (associative data structures) in Haskell. I find myself using them more than any other data structure, and I think there is no big deal in adding some sugar for this to the language. I could not find out whether such an extension is beeing discussed. If not, I would like to propose and extension. Any help and suggestions are very welcome here. Thanks. Also related to the topic: 1/ Is there a list of proposals for extensions to Haskell that has currently been accepted in the new standard? I have not found one on Haskell' ( http://hackage.haskell.org/trac/haskell-prime/query?status=newstatus=assignedstatus=reopenedgroup=state), but it looks outdated. No mentions to the new standard! 2/ I have seen somewhere a statement that a new language standard will be published yearly. Didn't happen until now. Is there even a new standard on the way? Cheers, Răzvan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [extension]syntactic sugar for maps
On 28 March 2013 06:30, Răzvan Rotaru razvan.rot...@gmail.com wrote: Hi, I am terribly missing some syntactic sugar for maps (associative data structures) in Haskell. I find myself using them more than any other data structure, and I think there is no big deal in adding some sugar for this to the language. I could not find out whether such an extension is beeing discussed. If not, I would like to propose and extension. Any help and suggestions are very welcome here. Thanks. What kind of syntactic sugar are you wanting? Also related to the topic: 1/ Is there a list of proposals for extensions to Haskell that has currently been accepted in the new standard? I have not found one on Haskell' (http://hackage.haskell.org/trac/haskell-prime/query?status=newstatus=assignedstatus=reopenedgroup=state), but it looks outdated. No mentions to the new standard! 2/ I have seen somewhere a statement that a new language standard will be published yearly. Didn't happen until now. Is there even a new standard on the way? Cheers, Răzvan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com http://IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [extension]syntactic sugar for maps
I'm genuinely curious as to how you use maps. I've found I use them far less in Haskell than in any other language: I only use them in select circumstances. And most of those uses would not benefit from a mayo literal. I suspect that many of the uses of map literals are better replaced with something like a record. This has the advantage of being static and more type safe. However, this is only based on my own use cases, so it's hard to generalize. On Mar 27, 2013 12:32 PM, Răzvan Rotaru razvan.rot...@gmail.com wrote: Hi, I am terribly missing some syntactic sugar for maps (associative data structures) in Haskell. I find myself using them more than any other data structure, and I think there is no big deal in adding some sugar for this to the language. I could not find out whether such an extension is beeing discussed. If not, I would like to propose and extension. Any help and suggestions are very welcome here. Thanks. Also related to the topic: 1/ Is there a list of proposals for extensions to Haskell that has currently been accepted in the new standard? I have not found one on Haskell' ( http://hackage.haskell.org/trac/haskell-prime/query?status=newstatus=assignedstatus=reopenedgroup=state), but it looks outdated. No mentions to the new standard! 2/ I have seen somewhere a statement that a new language standard will be published yearly. Didn't happen until now. Is there even a new standard on the way? Cheers, Răzvan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [extension]syntactic sugar for maps
On Wed, 2013-03-27 at 21:30 +0200, Răzvan Rotaru wrote: I am terribly missing some syntactic sugar for maps (associative data structures) in Haskell. I find myself using them more than any other data structure, and I think there is no big deal in adding some sugar for this to the language. I could not find out whether such an extension is beeing discussed. If not, I would like to propose and extension. Any help and suggestions are very welcome here. Thanks. http://hackage.haskell.org/trac/ghc/wiki/OverloadedLists comes to mind. Nicolas ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [extension]syntactic sugar for maps
Sorry, I forgot to explain (probably because I'm too used to it). I am
referring to a syntax for easy creation of maps. Something equivalent to
lists:
to build a list: [ 1, 2, 3]
to build a map; { 1, one, 2, two, 3, three}
Without it I am always forced to use fromList.
Răzvan
On 27 March 2013 21:48, Ivan Lazar Miljenovic ivan.miljeno...@gmail.comwrote:
On 28 March 2013 06:30, Răzvan Rotaru razvan.rot...@gmail.com wrote:
Hi,
I am terribly missing some syntactic sugar for maps (associative data
structures) in Haskell. I find myself using them more than any other data
structure, and I think there is no big deal in adding some sugar for
this to
the language. I could not find out whether such an extension is beeing
discussed. If not, I would like to propose and extension. Any help and
suggestions are very welcome here. Thanks.
What kind of syntactic sugar are you wanting?
Also related to the topic:
1/ Is there a list of proposals for extensions to Haskell that has
currently
been accepted in the new standard? I have not found one on Haskell'
(
http://hackage.haskell.org/trac/haskell-prime/query?status=newstatus=assignedstatus=reopenedgroup=state
),
but it looks outdated. No mentions to the new standard!
2/ I have seen somewhere a statement that a new language standard will be
published yearly. Didn't happen until now. Is there even a new standard
on
the way?
Cheers,
Răzvan
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--
Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com
http://IvanMiljenovic.wordpress.com
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[Haskell-cafe] Remove redundancy with Template Haskell
Hi Café, I have a function that looks like this: call :: SomeFunction - String - SomeState The string is actually the representation of the function passed in parameter. It is stored in the state for documentation. So a call looks like that: call (\a - putStrLn a) \a - putStrLn a There is a clear redundancy here, how could I remove it with Template Haskell? I cannot figure out... Thanks! Corentin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [extension]syntactic sugar for maps
Sorry, I forgot to explain (probably because I'm too used to it). I am
referring to a syntax for easy creation of maps. Something equivalent to
lists:
to build a list: [ 1, 2, 3]
to build a map; { 1, one, 2, two, 3, three}
Without it I am always forced to use fromList.
This looks like something to use records for, or in any case something
where association list performance is not an issue.
If you just want to store some configuration-like structure and pass it
around, a record is great for this. You might find where in other
languages you would simply leave a key null, in Haskell you can just fill
it with a Nothing.
Maps (hash or binary-tree) really pay off when they are filled dynamically
with massive numbers of associations. I find when I am ending up in this
scenario, I am generating my map programatically, not writing it as a
literal.
Sometimes people even write maps simply as functions and not even as a
data-structure.
myMap char = case char of
'a' - 1
'b' - 2
'c' - 3
Perhaps you could describe a situation you are in where you are wanting
this, and we could see if there is something you can do already that is
satisfying and solves your problem.
On Wed, Mar 27, 2013 at 12:59 PM, Eli Frey eli.lee.f...@gmail.com wrote:
http://hackage.haskell.org/trac/ghc/wiki/OverloadedLists comes to mind.
This assumes you can turn ANY list into a thing. Maps only make sense to
be constructed from association list. If I've got a [Char], how do I make
a map form it?
On Wed, Mar 27, 2013 at 12:56 PM, Nicolas Trangez nico...@incubaid.comwrote:
On Wed, 2013-03-27 at 21:30 +0200, Răzvan Rotaru wrote:
I am terribly missing some syntactic sugar for maps (associative data
structures) in Haskell. I find myself using them more than any other
data
structure, and I think there is no big deal in adding some sugar for
this
to the language. I could not find out whether such an extension is
beeing
discussed. If not, I would like to propose and extension. Any help and
suggestions are very welcome here. Thanks.
http://hackage.haskell.org/trac/ghc/wiki/OverloadedLists comes to mind.
Nicolas
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Re: [Haskell-cafe] Remove redundancy with Template Haskell
Hi Corentin, On Wed, Mar 27, 2013 at 09:13:41PM +0100, Corentin Dupont wrote: I have a function that looks like this: call :: SomeFunction - String - SomeState The string is actually the representation of the function passed in parameter. It is stored in the state for documentation. So a call looks like that: call (\a - putStrLn a) \a - putStrLn a There is a clear redundancy here, how could I remove it with Template Haskell? I cannot figure out... You can even use cpp to get something like: #define CALL(func) call (func) #func CALL(\a - a + 1) = call (\a - a + 1) \a - a + 1 Greetings, Daniel ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [extension]syntactic sugar for maps
I agree that fromList or pattern matching at the function or case level are
readable. We probably don't need new sugar. For what it's worth, in scala
you can use - to construct tuples, so you'll sometimes see maps created
like this:
Map(1 - one, 2 - two, 3 - foo)
You can always do something similar in haskell (keeping in mind that -
is reserved):
import qualified Data.Map as Map
(--) = (,)
makeMap = Map.fromList
myMap = makeMap [ 1 -- one
, 2 -- two
, 3 -- foo
]
Of course, it's not idiomatic and won't be immediately obvious to readers
that you are constructing tuples. However, if you find it easier to read
and need to write a lot of map literals in your code, it may be worth
coming up with a couple of aliases similar to those.
On Wed, Mar 27, 2013 at 1:16 PM, Eli Frey eli.lee.f...@gmail.com wrote:
Sorry, I forgot to explain (probably because I'm too used to it). I am
referring to a syntax for easy creation of maps. Something equivalent to
lists:
to build a list: [ 1, 2, 3]
to build a map; { 1, one, 2, two, 3, three}
Without it I am always forced to use fromList.
This looks like something to use records for, or in any case something
where association list performance is not an issue.
If you just want to store some configuration-like structure and pass it
around, a record is great for this. You might find where in other
languages you would simply leave a key null, in Haskell you can just fill
it with a Nothing.
Maps (hash or binary-tree) really pay off when they are filled dynamically
with massive numbers of associations. I find when I am ending up in this
scenario, I am generating my map programatically, not writing it as a
literal.
Sometimes people even write maps simply as functions and not even as a
data-structure.
myMap char = case char of
'a' - 1
'b' - 2
'c' - 3
Perhaps you could describe a situation you are in where you are wanting
this, and we could see if there is something you can do already that is
satisfying and solves your problem.
On Wed, Mar 27, 2013 at 12:59 PM, Eli Frey eli.lee.f...@gmail.com wrote:
http://hackage.haskell.org/trac/ghc/wiki/OverloadedLists comes to mind.
This assumes you can turn ANY list into a thing. Maps only make sense to
be constructed from association list. If I've got a [Char], how do I make
a map form it?
On Wed, Mar 27, 2013 at 12:56 PM, Nicolas Trangez
nico...@incubaid.comwrote:
On Wed, 2013-03-27 at 21:30 +0200, Răzvan Rotaru wrote:
I am terribly missing some syntactic sugar for maps (associative data
structures) in Haskell. I find myself using them more than any other
data
structure, and I think there is no big deal in adding some sugar for
this
to the language. I could not find out whether such an extension is
beeing
discussed. If not, I would like to propose and extension. Any help and
suggestions are very welcome here. Thanks.
http://hackage.haskell.org/trac/ghc/wiki/OverloadedLists comes to mind.
Nicolas
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