A .NET Bridge for Haskell
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Docs
Driver
Foreign
Generator
Samples
LICENSE
README
Salsa.cabal
Setup.hs
stack.yaml

README

                      Salsa: a .NET bridge for Haskell

  Salsa is an experimental Haskell library and code generator that allows
  Haskell programs to host the .NET runtime and interact with .NET libraries.
  It uses type families extensively to provide a type-safe mapping of the .NET
  object model in the Haskell type system.

What's in the package:

  * 'Foreign' contains the Haskell library 'Foreign.Salsa'.

    This library provides the Haskell-side interface to Salsa, including:
    functions to load the .NET runtime into the process, functions for
    interacting with .NET classes and objects, and the required type-level
    machinery.  It works together with the Haskell modules created by the
    generator (see below) to provide access to .NET classes and their members.

  * 'Driver' contains the Salsa .NET driver assembly (Salsa.dll).

    The driver assembly contains .NET code that is loaded automatically by the
    Salsa library when the .NET runtime is loaded into the process.  It
    provides run-time code generation facilities for calling in and out of the
    .NET runtime from Haskell.  The assembly binary (Salsa.dll) is embedded in
    'Foreign\Salsa\Driver.hs' using the 'Embed.hs' utility program.

  * 'Generator' contains the Salsa binding generator.

    The generator is a C# program that creates Haskell modules from .NET
    metadata to provide type-safe access to the requested .NET classes and
    methods in .NET assembilies.

    Note: the generator requires .NET 3.5 because it uses the 'System.Linq'
          namespace.

  * 'Samples' contains a few Haskell programs that use Salsa.

    - Hello:   a basic console 'Hello World' program.

    - Weather: a console program that asynchronously downloads the Sydney
               weather forecast and displays it.

    - Conway:  a simulator for Conway's Game of Life with a Windows
               Presentation Foundation GUI.  (Requires .NET 3.0 or later.)

Requirements:

  * GHC 7.8.x

    Salsa makes use of extensions that have only been available since version
    7.8 of GHC.

    Additionally, GHC >= 7.10 cannot be used very effectively due to
    implementation details of the type checker that make use of type families
    too strict, and hence exhaust all the memory and/or take a long time when
    trying to resolve from a small handful of method overloads.

  * Microsoft .NET Framework 3.5 / Mono

    Since the Generator requires .NET 3.5, any Salsa development also requires
    this version.  Executables produced with Salsa however will run with just
    .NET 2.0 (provided that only .NET 2.0 assemblies are used by the program).

    Salsa will not work with versions 1.0/1.1 of the .NET Framework.

    Additionally, Microsoft .Net 4.0 introduced a new version of the runtime
    (<4.0 all used the separate 2.0 runtime), which currently has a major
    unresolved issue in that it doesn't work when called from Haskell.

    Building with Mono and running Salsa executables on Mono works. Salsa
    will be built with Mono if not running on Windows or the flag 'use_mono'
    is set to true.

Building:

  * Build the Salsa.dll driver assembly (see the README file within the Driver
  directory).
  * Build the generator (see it's associated README also).
  * Run the generator against the import files for each of the sample executables
  to be included
  * Run stack build

Authors:

  Andrew Appleyard
  Tim Matthews