December 2008 - Libraries

[Haskell] ANNOUNCE: ChristmasTree 0.1 (excuses for second attempt)
by S.Doaitse Swierstra 07 Dec '08

07 Dec '08

We are pleased to announce the availability of the package "ChristmasTree", which contains the code associated with our paper at the last Haskell symposium: @inproceedings{1411296, author = {Marcos Viera and S. Doaitse Swierstra and Eelco Lempsink}, title = {Haskell, do you read me?: constructing and composing efficient top-down parsers at runtime}, booktitle = {Haskell '08: Proceedings of the first ACM SIGPLAN symposium on Haskell}, year = {2008}, isbn = {978-1-60558-064-7}, pages = {63--74}, location = {Victoria, BC, Canada}, doi = {http://doi.acm.org/10.1145/1411286.1411296}, publisher = {ACM}, address = {New York, NY, USA}, } The name of the package stands for: "Changing Haskell's Read Implementation Such That by Manipulating Abstract Syntax Trees it Reads Expressions Efficiently" which, given the time of year, seems appropriate. Feel free to download and unpack this "present" at what for the Dutch is called "Sinterklaasavond" (http://en.wikipedia.org/wiki/Sinterklaas) Arthur Baars Marcos Viera Eelco Lempsink Doaitse Swierstra PS: the package uses our library supporting transformation of typed abstract syntax, which we placed in a separate package TTTAS

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[Announce] TTTAS (with excuse for second attempt to post)
by S. Doaitse Swierstra 07 Dec '08

07 Dec '08

We are pleased to announce the availability of the package "TTTAS", which contains the code associated with our paper at the coming TLDI workshop: \@inproceedings{ BSV09, author = {Arthur Baars and S. Doaitse Swierstra and Marcos Viera}, title = {Typed Transformations of Typed Abstract Syntax}, booktitle = {TLDI '09: fourth ACM SIGPLAN Workshop on Types in Language Design and Implementation}, year = {2009}, location = {Savannah, Georgia, USA}, publisher = {ACM}, address = {New York, NY, USA}, } For more information see: http://www.cs.uu.nl/wiki/bin/view/Center/TTTAS Arthur Baars Marcos Viera Doaitse Swierstra

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Building haddock when accessing data files from package code
by Hugo Pacheco 03 Dec '08

03 Dec '08

Hi all, When creating a cabal package that contains module that import Paths_<mybraryname> (as tutored in http://www.haskell.org/cabal/release/latest/doc/users-guide/authors.html#pa…) haddock complains that it cannot find such module, since it is generated automatically by cabal: $ runhaskell Setup.lhs haddock ... Setup.lhs: can't find source for module Paths_GHood How do I tell haddock to ignore such module? Should this be handled in the Setup.lhs file? I am using the default Simple file. Thanks in advance, hugo -- www.di.uminho.pt/~hpacheco

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Binary Trees missing on hackage
by Christian Maeder 02 Dec '08

02 Dec '08

Hi, I was surprised that I could not find a "classical" binary tree data structure on hackage, mainly for teaching purposes, like: data BinTree a = Nil | Node (BinTree a) a (BinTree a) with a couple of utility functions and instances (i.e. in-order traversal). Surely, one may argue, that such a tree can always be defined on the fly when needed, but nobody would argue so for lists or tuples. (Although I've rarely seen someone redefining lists, it is quite common to introduce user-defined products or enumerations.) There are rose trees in Data.Tree and many other variants of trees are conceivable, ie. data Boom a = Leaf a | Node (Boom a) (Boom a) or a kind of combination: data BinLeafTree a b = Leaf b | Node (BinLeafTree a b) a (BinLeafTree a b) I don't know, why I find the above BinTree most important. I'm not even sure if such a tree could be re-used for Search- or AVL-trees that need strict fields with redundant size or height counters for efficiency reasons. In any case I would find such a data type at least as useful as http://hackage.haskell.org/cgi-bin/hackage-scripts/package/OneTuple Who would supply and maintain such a package? Or did I simply not search hard enough? Cheers Christian P.S. I took the (non-empty) "Boom" from the Boom-Hierarchy described in "An Exploration of the Bird-Meertens Formalism" by Roland Backhouse 1988, Groningen

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Profiling options
by Axel Simon 01 Dec '08

01 Dec '08

Hi all, I'm trying to build a library with Cabal and then profile certain modules. I'm not very proficient with profiling, so it might be genuinely wrong what I'm doing. I compile my library with --enable-library-profiling and at the moment have ghc-prof-options: -auto-all in my cabal file. However, I only want to use -auto in one core module since seeing all the other functions is just obfuscating the profile since the costs are also accredited to callers of the functions that I want to profile. I tried to use {-# OPTIONS -auto #-} in the specific module but ghc ignores this since -auto is a static option. Cabal, on the other hand, does not allow me to add an option when compiling a specific module. It it true that I'm stuck with using -auto on either all or no module when I build my library using Cabal? The only thing on profiling and Cabal I've found is Ticket #200, however, this ticket seems to advocate that the user never needs any control over what is being profiled and what is not. So, is my attempt to profile a single module really a stupid idea or is it Cabal that should provide better support for profiling individual modules? Thanks, Axel.

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How to expose cabal-generated installation paths?
by Peter Simons 01 Dec '08

01 Dec '08

Hi, please pardon me if this question is not appropriate for this forum or if there is a document that answers my question already. I had no better idea but to ask here and I'd be happy to receive pointers into the right direction. Recently, I received a patch for the FuncMP package [1] that exposes the Cabal-generated "Paths_funcmp" module. It appears, however, that Cabal doesn't find that module when running the 'haddock' target: | Creating dist/doc/html/funcmp (and its parents) | Preprocessing library funcmp-1.2... | Running hscolour for funcmp-1.2... | Creating dist/doc/html/funcmp/src (and its parents) | /usr/local/bin/HsColour -print-css -odist/doc/html/funcmp/src/hscolour.css | cabal-setup: can't find source for module Paths_funcmp The complete log is available at [2]. Does anyone know, by any chance, a simple way to remedy that problem? Peter [1] http://hackage.haskell.org/cgi-bin/hackage-scripts/package/funcmp [2] http://hackage.haskell.org/packages/archive/funcmp/1.2/logs/failure/ghc-6.10

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