- Libraries - Haskell.org

The Data.Array.* hierarchy is unsafe (or, Segfaulting for fun and profit)
by Spencer Janssen 11 Dec '06

11 Dec '06

I've discovered a problem in the array libraries that allows one to read arbitrary memory locations without the use of any unsafeFoo functions. Both GHC and Hugs are affected. > import Data.Array.IArray > import Data.Array.Unboxed Here is a poorly behaved instance of Ix: inRange and index ignore the bounds supplied. > newtype EvilIx = E Int deriving (Eq, Ord) > instance Ix EvilIx where > inRange _ _ = True > index _ (E i) = i > range (E x, E y) = map E $ range (x, y) One can read arbitrary memory locations, eventually indexing far enough to cause a segmentation fault. > main = print [a ! E (2^i) | i <- [0..]] > where > a :: UArray EvilIx Int > a = array (E 0, E 0) [] This problem is not specific to UArrays: > main' = print [a ! E (2^i) | i <- [0..]] > where > a :: Array EvilIx String > a = array (E 0, E 0) [] The issue is that the array operators trust the Ix instance to manage boundaries correctly. The solution is to double check the value returned by index with the actual length of the array. I volunteer to write the fix, if I can extract some hints from more knowledgeable folk. There's sizeOfByteArray#, is there an analog for an Array#? I need to know how to find the length of Hugs array primitives too. Cheers, Spencer Janssen

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Wanted: documentation for STM
by dons＠cse.unsw.edu.au 11 Dec '06

11 Dec '06

Could someone who's used the STM subsystem submit a haddock documentation patch. Looking here: http://www.haskell.org/ghc/docs/latest/html/libraries/stm/Control-Concurren… is embarrassing. -- Don

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Library name choice for network accept loop module under development
by Cat Dancer 11 Dec '06

11 Dec '06

I am working on a library module to implement a network accept loop with graceful shutdown. (See http://code.catdancer.ws/acceptloop/) This code is tricky to get right, so if I am successful, it will be useful to projects such as web or database servers which accept network connections and would like to be able to restart gracefully without dropping or losing connections. Is "Network.AcceptLoop" a good name for this module in the hierarchical library namespace?

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darcs patch: Add documentation for TChan (and 1 more)
by Spencer Janssen 11 Dec '06

11 Dec '06

Mon Dec 11 01:12:01 CST 2006 Spencer Janssen <sjanssen(a)cse.unl.edu> * Add documentation for TChan Mon Dec 11 01:43:18 CST 2006 Spencer Janssen <sjanssen(a)cse.unl.edu> * Add documentation for TMVar.

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darcs patch: Fix missing comma in Fractional documentation
by Alec Berryman 11 Dec '06

11 Dec '06

Fri Dec 1 12:32:37 EST 2006 Alec Berryman <alec(a)thened.net> * Fix missing comma in Fractional documentation

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Library docs on Debian
by Yitzchak Gale 10 Dec '06

10 Dec '06

It used to be that the Haddock docs for all of the standard libraries were automatically installed on my Debian system together with GHC. I could browse them conveniently through a single consolidated index. But now that I have upgraded to GHC 6.6, many of them are gone. The packages that I most yearn for are mtl and network. What is the new Right Way to install these docs on a Debian system? Thanks, Yitz

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Re: Data.List documentation improvements
by Andriy Palamarchuk 08 Dec '06

08 Dec '06

The deadline for this update is up. Can somebody commit the changes for me? Here is the ticket with the patch: http://hackage.haskell.org/trac/ghc/ticket/1034 Andriy ____________________________________________________________________________________ Want to start your own business? Learn how on Yahoo! Small Business. http://smallbusiness.yahoo.com/r-index

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Re: Data.List documentation improvements
by Andriy Palamarchuk 07 Dec '06

07 Dec '06

Iavor, thank you for the feedback. ----- Original Message ---- From: Iavor Diatchki <iavor.diatchki(a)gmail.com> > instead of adding examples to the documentation, wouldn't it be better > to have a wiki site that documents the libraries, and everyone can add > examples there. I am thinking something along the lines of: > http://us2.php.net/manual/en/function.fopen.php Depends on what examples we are talking about. I'm strongly in favor of including examples explaining API definition and intended usage in the library documentation. Think about these examples as of other way of defining the API. Code can explain some things much better that words, right? On other hand examples of using API in broader context, recipes, design patterns, discussions do not belong to the API documentation, though some information can eventually migrate there :-) > PS: I find the darcs patches that are being sent _very_ unreadable: > they contain tons of information that is not at all relevant to the > change that was made. Is there a simpler way to show what was done? > Perhaps a simple diff? Isn't header of the darcs patch is essentially a diff? I agree with you that darcs patch takes a lot of space because of additional data. To work around that one can attach patches to the ticket instead of emailing them to the list. Ticket for this problem is: http://hackage.haskell.org/trac/ghc/ticket/1034 Besides the patch you'll find there HTML document with haddock output from the changes. Andriy ____________________________________________________________________________________ Do you Yahoo!? Everyone is raving about the all-new Yahoo! Mail beta. http://new.mail.yahoo.com

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Re: Re[2]: [GHC] #974: Add unzipEithers, lefts, rights to Data.Either
by Andriy Palamarchuk 07 Dec '06

07 Dec '06

Sorry, I was not subscribed when the discussion started. I do not mind against name separateEithers. A couple of ideas: * decideEithers (or decideOnEithers). * an entry from thesaurus for "split" (http://thesaurus.reference.com/browse/split) may help to pick good name: bifurcate, branch, break, burst, cleave, come apart, come undone, crack, dichotomize, disband, disjoin, dissever, disunite, diverge, divide, divorce, fork, gape, give way, hack, isolate, open, part, part company, pull apart, put asunder, rend, rip, rive, separate, sever, splinter, sunder Andriy PS: "bifurcateEithers" - good candidate for a spelling bee :-))) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: [GHC] #974: Add isLeft, isRight, fromLeft, fromRight, and splitEithers to Data.Either
by dons＠cse.unsw.edu.au 07 Dec '06

07 Dec '06

ndmitchell: > Hi > > >#974: Add isLeft, isRight, fromLeft, fromRight, and splitEithers to > >Data.Either > > Woohoo! Finally! > > >This proposal would add basic functionality to `Either` similar to that > > for `Maybe`. The `splitEithers` function of type `[Either a b] -> > > ([a],[b])` is unique; however, it seems to be a widely useful function. > > This (in my mind) is a parallel to unzip? unzipEithers to me gives a > much clearer picture of what is going on here. yeah, if its an unzip, then unzipEithers makes more sense. -- Don

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