Commercial Users of Functional Programming Workshop (CUFP) 2009

          Functional Programming As a Means, Not an End

                      Call for Participation

                       Sponsored by SIGPLAN
                    Co-located with ICFP 2009
    _________________________________________________________

                         4 September 2009
                       Edinburgh, Scotland

                     Registration is through
           http://www.regmaster.com/conf/icfp2009.html
    _________________________________________________________

  Functional languages have been under academic development 
  for over 25 years, and remain fertile ground for programming
  language research. Recently, however, developers in industrial, 
  governmental, and open source projects have begun to use 
  functional programming successfully in practical applications. 
  In these settings, functional programming has often provided 
  dramatic leverage, including whole new ways of thinking about 
  the original problem.

  The goal of the CUFP workshop is to act as a voice for these
  users of functional programming. The workshop supports the
  increasing viability of functional programming in the
  commercial, governmental, and open-source space by providing a
  forum for professionals to share their experiences and ideas,
  whether those ideas are related to business, management, or
  engineering. The workshop is also designed to enable the
  formation and reinforcement of relationships that further
  the commercial use of functional programming. Providing user
  feedback to language designers and implementors is not a
  primary goal of the workshop, though it will be welcome if it
  occurs.

Program

  CUFP 2009 will last a full day and feature a discussion
  session and the following presentations:

  Bryan O'Sullivan
         Keynote: Real world Haskell

  Lee Momtahan (EDF Trading)
         Implementing a Domain-Specific Language for Derivative
         Pricing with Scala

  Bhasker Kode (hover.in)
         Erlang at hover.in

  Jefferson Heard, (Renaissance Computing Institute)
         Teleconferencing over High-res Maps with Haskell

  Alex Peake (TFC) and Adam Granicz (Intellifactory)
         The First Substantial Line of Business Application in F#

  Christopher Piro and Eugene Letuchy (Facebook)
         Functional Programming at Facebook

  Fermin Reig (Morgan Stanly)
         Computing with Time Series Data in Finance

  Warren Harris (Metaweb)
         Functional Programming at Freebase

  Mark Wong-VanHaren (Glyde)
         Clear & Simple: Composing a Marketplace

  Duncan Coutts (Well-Typed)
         Birth of the Industrial Haskell Group

  There will be no published proceedings, as the meeting is
  intended to be more a discussion forum than a technical
  interchange.

  See http://cufp.galois.com for more information, including
  presentation abstracts and the most recent schedule
  information.

  This will be the sixth CUFP; see CUFP 2004 CUFP 2005, CUFP
  2006, CUFP 2007 and CUFP 2008 for information about the
  earlier meetings, including reports from attendees and video
  of the most recent talks.

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Hello,

I made a GCL compiler using Alex and Happy and now I'm making the interpreter to that program. Here's the deal:

First of all, I'm no expert in the usage of monads. Now:

Whenever a "show" instruction is found in any GCL program while the interpretation is being done it is supposed to print on the stdout the string or the aritmetic expresion it was called with, so I guessed I need to run an IO operation and continue the interpretation of my program. I managed to do this using unsafePerformIO and `seq` like is shown below. My question is: Is it safe to use it this way? So far it is working great, but I need to be sure I'm using it in a "safe" way. Like I said, I'm no expert in monads and the System.IO.Unsafe documentation says:

"

unsafePerformIO :: IO a -> a

This is the "back door" into the IO monad, allowing IO computation to be performed at any time. For this to be safe, the IO computation should be free of side effects and independent of its environment.
"

I don't know if the IO computation I'm doing is free of side effects and independent of its enviroment :s. (is just hPutStr stdout ....)

Also I've read something about my code not being executed for sure or something like that. Can somebody check the code and tell me if I'm "safe" with it?

Thanks a lot!

Here's the code:

-- Tabla is my Symbol Table of the program being interpreted
evalInstruccion:: Instruccion -> Tabla -> Tabla
evalInstruccion (ShowY showY) tabla = myRunIO (evalShow showY tabla)
evalInstruccion _ tabla = tabla      -- There are many other Instructions here missing wich are not relevant to my question

{-# NOINLINE myRunIO #-}
myRunIO:: (Tabla, IO()) -> Tabla
myRunIO tupla = ((unsafePerformIO (snd tupla)) `seq` (fst tupla)) -- Here's the unsafePerformIO.... Am I safe?

evalShow:: ShowY -> Tabla -> (Tabla, IO())
evalShow (ShowS string) tabla = (tabla,(hPutStr stdout string))
evalShow (ShowE expr) tabla = (tabla,(hPutStr stdout (show (evalExpr expr tabla)))) -- Don't worry about evalExpr, it works and returns an Int

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Announcing happstack-0.3.2:

It was released several days ago to hackage, but here is the official announcement!

List of recorded changes (many improvements were not documented):

* Modularization of the example application using the component system
* All packages now require Cabal >= 1.6
* Repository metadata added to cabal description
* Moved Combined Logging from Happstack.Server to Happstack.Server.AccessLog.Combined
* Added Happstack.Util.Mail: a simple email interface which utilizes a smarthost
* SimpleHTTP: look and lookPairs now assume utf-8 from the browser
* Space leak fixed in Happstack.Util.Timeout
* A fix for an issue where alphanumeric Accept-Encoding Requests made the parser fail
* Fixes for some command-line browsers such as links
* Guards now have fall-through semantics
* Various updates & additions to documentation
* Code beautification
* Bugfix to Happstack.Util.Cron to accept intervals up to maxBound
* addition of a strict version of fileServe "fileServeStrict"
* fileServe (lazy) behaves more reliably now and escapes before any filters can be applied
Regards,
Matthew Elder

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