Re: [Haskell-cafe] Value-weak hash tables in Haskell ?
There is supposed to be some weak hash map implementation somewhere. However, if you can't find it you can easily create it yourself. However, you will need to use the map in IO so I suggest that you use the hashtables[1] package in combination with the weak pointers mentioned by Erik. - Alessandro [1]: http://hackage.haskell.org/package/hashtables On 10 aug. 2013, at 21:08, Erik Hesselink hessel...@gmail.com wrote: I'm not sure, but there are weak pointer [0], though I have never used them. Erik [0] http://www.haskell.org/ghc/docs/latest/html/libraries/base/System-Mem-Weak.html On Sat, Aug 10, 2013 at 7:13 PM, Aleksey Uymanov s9gf4...@gmail.com wrote: Hello, haskellers. Is there any package implementing magic hash tables weak in value? I mean when the value is garbage collected, then this key+value authomatically removes from the hash table. -- Aleksey Uymanov s9gf4...@gmail.com ___ 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 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Is inspectable recursion in Arrows possible?
Dear all,
I am trying to find a way to translate normal recursive notation such
as the |fib| function below to an arrow, retaining as much of the
structure of the recursive notation as possible. In addition I would
like to inspect the arrow. For this I created a datatype containing a
constructor for each Arrow{..} class:
Fib:
fib 0 = 0
fib 1 = 1
fib n = fib (n-2) + fib (n-1)
My R datatype, the instances for this datatype consist of the mapping
to the appropriate constructor:
data R x y where
-- Category
Id :: R a a
Comp :: R b c- R a b - R a c
-- Arrow
Arr :: (a - b) - R a b
Split:: R b c- R b' c'- R (b,b') (c,c')
Cache:: (a - a - Bool) - R a a
-- ArrowChoice
Choice :: R b c - R b' c' - R (Either b b') (Either c c')
-- ArrowLoop
Loop :: R (b, d) (c, d) - R b c
-- ArrowApply
Apply:: R (R b c, b) c
Translating the |fib| function from above first resulted in the
following definition. It is not allowed however due to the proc n on
the RHS of the declaration for |fibz|. I know that the grammar of the
Arrow Notation prevents this, but what is the underlying reason for
this?
fib' :: (ArrowChoice r, ArrowLoop r) = r Int Int
fib' = proc x - do
rec fibz - proc n - case n of
0 - returnA - 0
1 - returnA - 1
n' - do l - fibz - (n'-2)
r - fibz - (n'-1)
returnA - (l+r)
fibz - x
Rewriting the function above to use a let statement compiles. However,
here my second problem arises. I want to be able to inspect the
recursion where it happens. However, in this case |fibz| is an
infinite tree. I would like to capture the recursion into fibz, I
hoped the rec would help me with that in combination with |loop| but
maybe I am wrong?
fib'' :: (ArrowChoice r, ArrowLoop r, ArrowApply r) = r Int Int
fib'' = proc x - do
let fibz = proc n - case n of
0 - returnA - 0
1 - returnA - 1
n' - do l - fibz - (n'-2)
r - fibz - (n'-1)
returnA - (l+r)
fibz - x
Basically, is it possible to observe this kind of recursion? (Perhaps
even within the boundaries of Arrow Notation) I could perhaps add
another constructor like fix.
Any thoughts on this?
Cheers,
Alessandro Vermeulen
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Re: [Haskell-cafe] Connecting Travis CI and hackage
You have full internet access on the Travis machines. The problem is that you only have the data from your public repo. So you could upload the package through the command line with cabal. But that means storing your credentials in the public repository, which is a bad idea obviously. In short: contact the people from Travis and they will be happy to help you. Maybe you can store some environment variables in your account that are made available for the build script. - Alessandro On Jul 8, 2012 7:28 PM, Dmitry Malikov malikov@gmail.com wrote: But in the meantime, regarding what you suggest here, couldn't be done through tags rather than branches? Tagging a release version could trigger testing and, if testing runs fine, upload to hackage. Testing should be done on travis virtual machine. So this question is not about `when' or `where from' new release should be generated. It's about how uploading the new package to hackage could be done from the travis machine. -- Best regards, dmitry malikov ! __**_ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/**mailman/listinfo/haskell-cafehttp://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] lhs2tex-hl 1.4.3 released
Dear all, I've uploaded a new version of lhs2tex-hl [1] to hackage [2]. It includes: 1. It now builds on GHC 7.2.x 2. You can list the LaTeX commands you have to implement (with a default implementation) with lhs2TeX-hl --action=ListCommands 3. Binary operators should now be typeset correctly. What does it do? It generates formatting statement for highlighting your Haskell code in your lhs2TeX compatible documents. Generate a fmt file with lhs2TeX-hl -o file.fmt file.lhs and add the following to your lhs file: %include file.fmt Have fun With kind regards, Alessandro Vermeulen [1] https://github.com/spockz/lhs2texhl [2] http://hackage.haskell.org/package/lhs2TeX-hl___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
