- Yhc - Haskell.org

CouchDB module in Yhc source tree: clarification, and small problems with other packages
by Dimitry Golubovsky 05 Jan '08

05 Jan '08

Hi, Don asked: > Are we likely to see the couchdb bindings released as a standalone > library for the wider community? Let me explain a little bit why the CouchDB module appears in the Yhc repo. As the next stage of the Yhc/Javascript project, I am trying to set up a web service where people might upload some Haskell code (or reference to such code, these details haven't been clarified yet), and get it compiled by background Yhc/ycr2js batch job, returning a HTML page with Javascript in response. CouchDB was picked* as intermediate storage for this project. Therefore an interface module was needed, so I wrote one. This module, `Database.CouchDB' is not 100% finished; it was coded up to satisfy the needs of the first utility I wrote, `cdbup' which is currently capable of uploading a text (utf-8 expected) or a binary file as a document attachment to CouchDB. So some functionality hasn't been coded yet, although it will definitely be, as the project develops. Regarding packaging, I hope I will eventually put it on Hackage, but there are some problems with another packages which I'll try to explain here, so maybe those packages' developers suggest something. 1. Text.JSON. This module was picked from Jun Mukai's haskellnet package (http://darcs.haskell.org/SoC/haskellnet/) One problem with this package, it needs too many dependencies (while JSON module relies only on Packrat parser). I had to extract the JSON module into Yhc tree; can the haskellnet package be split somehow into orthogonal sub-packages, and maybe one toplevel package which would pull all parts together if used? 2. Text.JSON again. I had to change the pNumber function (parser for numeric nodes) replacing the '1'..'9' digits range with '0' .. '9'. Otherwise it did not handle JSON-encoded numbers equal to zero. I am not sure I was 100% right, so perhaps some JSON experts here might correct me. 3. Packrat parser does not seem to be packaged anywhere else, does it? 4. The dataenc package (http://code.haskell.org/dataenc/devo/) from which I pulled the Codec.Binary.Base64 module. The package may need some adjustment to GHC 6.8.x packages structure as only "base" listed in build-depends does not seem to be enough: when building it, Cabal complains for hidden packages such as collections (which I had to add manually to the cabal file), etc. Is it some problem with my GHC setup, or does just the dataenc.cabal need to be updated? So, in order to get things done quicker, I pulled the said pieces from their packages into Yhc tree. For packaging the CouchDB interface, definitely these duplicates need to be removed. Other packages that CouchDB relies upon, are**: base, network, HTTP, filepath, base64-string, utf8-string Thanks for the interest in CouchDB interface, and feel free to ask any questions. --- * before support form IBM/Apache was announced, but this recent development definitely increases interest to CouchDB ** Just from the -package options I used to compile it; I may have something omitted here. -- Dimitry Golubovsky Anywhere on the Web

1 0

Cannot rebuild Yhc after fullclean (problem with Uniplate)
by Dimitry Golubovsky 21 Dec '07

21 Dec '07

Neil, As I upgraded to GHC 6.8.2, I am trying to do full clean and rebuild of Yhc. I am getting an error: ====================================== Getting dependencies for depends/uniplate/Data/Generics/PlateInternal.hs. Unable to open 'depends/uniplate/Data/Generics/.PlateInternal.hs.dep'. Dependencies will not be calculated. "ghc" -i./src/compiler -i./src/libraries/general -i./src/libraries/core -idepends/cpphs -idepends/filepath -idepends/uniplate -i./src/interactive -package mtl -package containers -package pretty -package packedstring -c depends/uniplate/Data/Generics/PlateInternal.hs -o depends/uniplate/Data/Generics/PlateInternal.o Getting dependencies for depends/uniplate/Data/Generics/Uniplate.hs. scons: *** Source `depends/uniplate/Data/Generics/Str.hi' not found, needed by target `depends/uniplate/Data/Generics/Uniplate.o'. Stop. scons: building terminated because of errors. ====================================== SConscript in depends/uniplate does not mention Str. Even if I add it there manually, I end up with error compiling Yhc.Core.Uniplate because of uniplateOnList not in scope, but it is commented out in Data.Generics.UniplateOn If I uncomment it, there is a problem with contexts, etc... Anything happened to Uniplate? Thanks. -- Dimitry Golubovsky Anywhere on the Web

2 4

how do I get yhe?
by Thomas Hartman 12 Dec '07

12 Dec '07

I am playing with yhc and ycr2js. When I built yhc, yhe didn't get created, which means I can't do stuff ghc has accustomed me to, like get the type of a value. Feels a bit crippling. Can yhe do this? And if so... how do I build yhe? thomas. --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

2 1

Re: [Haskell-cafe] Re: regex package for yhc?
by Neil Mitchell 11 Dec '07

11 Dec '07

Hi > I cannot quickly find on http://www.haskell.org/haskellwiki/Yhc what YHC supports. >From the (just modified) FAQ: http://www.haskell.org/haskellwiki/Yhc/FAQ#Language_Support Q) What extensions does it support? A) Very few. Existentials and pattern guards are supported. Rank-2 types, multiparameter type classes and most other extensions are not. Thanks Neil

1 0

ycr2js interactive debugging with firebug?
by Thomas Hartman 07 Dec '07

07 Dec '07

Is it possible to compile a javascript program such that you can fire one of the functions from firebug for interactive javascript debugging? (Firebug is a free javascript debugging plugin to firefox). For instance I would like to be browsing http://darcs.haskell.org/yhc/web/jsdemos/HsWTKDemo.html and in firebug, type some somefunction(3) and have it calculate factorial of 3 in the firebug console. First of all, not sure if this question even makes sense given the continuation passing model for ycr2js. \ Secondly, if this is theoretically possible, is there a sane way to either flag the factorial function so that it is obvious what it is in the generated javascript, or to "reverse engineer" the javascript to figure out what function is doing the factorial? thomas. --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

1 0

how to compile this in yhc?
by Thomas Hartman 07 Dec '07

07 Dec '07

Is there some way to compile the following function in yhc? works in ghc with glasgow exts deactivated, yhc complains context for Prelude.read needed (in final line) readfloat :: String -> Maybe Float readfloat x | null parse || not (null leftover) = fail $ "myRead: "++x | otherwise = return v where parse@((v,leftover):ps) = readsPrec 0 x thanks! --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

2 1

regex package for yhc?
by Thomas Hartman 06 Dec '07

06 Dec '07

Is there some way to use any of the various regex packages on hackage via yhc? Has anyone installed one them successfully? I'd like regex-tdfa, but would settle for regex-posix, or really, anything that brings the convenience of regex to yhc. In general, is there a straightforward way to install "extralibs" type packages for universal "import" availability in yhc? Is there a cabal equivalent for yhc? Documentation pointer would be appreciated; I searched but couldn't find anything. Maybe not using the right keywords... t. --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

1 1

buildbot failure in windows
by andrewjwilkinsonw＠gmail.com 06 Dec '07

06 Dec '07

The Buildbot has detected a new failure of windows. Full details are available at: http://www.indiegigs.co.uk:8010/windows/builds/212 Buildbot URL: http://www.indiegigs.co.uk:8010/ Buildslave for this Build: neilwindows Build Reason: Build Source Stamp: HEAD Blamelist: golubovsky(a)gmail.com BUILD FAILED: failed failed slave lost sincerely, -The Buildbot

1 0

Yhc/Javascript project/status documentation clarification
by Dimitry Golubovsky 04 Dec '07

04 Dec '07

Hi, As I see some increasing interest to the Javascript backend I am developing, first of all I would like to thank everybody who contacted me on this matter. I would like to give a clarification on the project's current status, and usability of the documentation that is available on Haskell Wiki. 1. History and status of the project. The project was "officially" started about 1.5 years ago. In November 2006, the first public announcement was made, with so called "Echo Demo Program" presented. Since then, a work was done on improvement of Javascript generation from Core, and also on low-level support of DOM which was achieved by automatic conversion of slightly patched IDL specifications available from the Web Consortium. Currently DOM Level2 is supported; Level1 was imported earlier, but all higher level functionality is added with respect to Level 2; usage of Level 1 is discouraged. After low-level interfaces with Javascript and DOM were settled, some experiments were carried out to test various programming paradigms for the high level interfaces with understanding that direct DOM manipulation differs little from usage of Javascript itself. Finally, from several concepts existing for Haskell GUI, some programming paradigm was distilled out, which is currently being worked on under the name of "Haskell Web Toolkit". At the moment, this is considered that the paradigm choice has been finalized, and the project is in the stage of proper documenting and polishing of the existing code, and creation of the widget library for practical use. Some examples could be seen in the recently published demo program at http://darcs.haskell.org/yhc/web/jsdemos/HsWTKDemo.html . 2. Available documentation Over the course of development, some draft documentation was published on the Haskell Wiki. As the coding approaches changed, parts of this documentation might have become partially or completely incorrect. I am now working on putting this in order, and for the time being I'd like to give some clarifications re garding existing documentation's usability. Brief Overview http://www.haskell.org/haskellwiki/Yhc/Javascript/Brief_overview This is a very general description, and its statements still hold. Users Guide http://www.haskell.org/haskellwiki/Yhc/Javascript/Users_guide The "Downloading" and "Build prerequisites" sections are correct. Same about "Building on Unix/Windows". "What is installed": now much more is installed, but general directory structure remains the same. "Compiling Haskell to Core", "Converting Core into Javascript", and "Building a XHTML Page" still valid in general, but see http://www.golubovsky.org/repos/wsptest/Makefile for better example of tools usage. "All togeher: a simple Makefile" is not correct: use a Makefile mentioned above. Programmers Guide http://www.haskell.org/haskellwiki/Yhc/Javascript/Programmers_guide "Up from the ground" Refers to the first historical Echo Demo Program. Although commented in great detail, no longer usable. This is kept for historical purposes only. The rest of the document is generally usable with the current state of the backend, but it does not cover the HsWTK programming paradigm at all. All examples referring to DOM.Level1 should be treated as if they referred to DOM.Level2, but at this level there are no major differences between DOM levels. "Threads and events" This section was added recently, after successful experiments with CPS and cooperative threads (or rather coroutines), Usable, except for the Message Boxes section: the Control.Concurrent.JSThreads module offers a better imolementation of message boxes. "Inner workings" http://www.haskell.org/haskellwiki/Yhc/Javascript/Inner_workings This was an attempt to describe the internals of the "spineful tagless machine" implemented in Javascript as the central part of the backend runtime. It is about 75% correct as structure of HsFun and HsDly objects varied slightly over time, but the general principles are still there. 3. Conclusion I am hoping that this message answers many questions of people potentially interested in using of this technology. Please feel free to contact me (golubovsky(a)gmail.com) with any suggestions and constructive critics. I am going to work on improving the project documentation for some time, but if anybody believes that some funcitonality might be now added to the supporting libraries, I am open for discussions. Thanks again. -- Dimitry Golubovsky Anywhere on the Web

1 0

tbody creation missing from javascript creation functions?
by Thomas Hartman 04 Dec '07

04 Dec '07

Grepping around, I see functions for table creation / manipulation in the javascript DOM stuff, but nothing for the tbody tag. Is this because it's missing from the IRL DOM specification, or a bug, or what? Should I add functionality for creating this tag myself, or is it easier to fix the generated haskell? I ask because the place where I want to use this javascript from haskell stuff should be making a tbody embedded in a div that is smaller than the tbody; in modern browsers renders as a table with scrollbars. Thanks, thomas. thartman@none:~/haskell-installs/yhc-install/yhc/src/translator/js/lib/haskell/DOM/Level1>grep -irl mkTable * | grep .hs HTMLTableColElement.hs HTMLTableElement.hs HTMLTableSectionElement.hs Html.hs_unsplit thartman@none:~/haskell-installs/yhc-install/yhc/src/translator/js/lib/haskell/DOM/Level1>grep -irl tbody * | grep .hs thartman@none:~/haskell-installs/yhc-install/yhc/src/translator/js/lib/haskell/DOM/Level1>cd ..

2 5