ANNOUNCE: Haskell/Java VM Bridge 0.2 Release

Ashley Yakeley
Thu, 10 Apr 2003 09:37:58 -0700

Release 0.2 of Haskell/Java VM Bridge is now available in source-code 

New in Version 0.2:


	* 'Haskell' now a separate Autotools project installing in 

	* New array region access functions

	* Correct array types in autogenerated class interfaces

	* Subtype parameters in autogenerated class interfaces

	* VMLayer 'env' parameter now implicit

	* Various changes in the BasicLayer

	* new native StartExecuteFunction function called by 
getExecuteFunctionClass, defineCallbackClass


	* Mac OS X support
	* Beginnings of MinGW32/Cygwin support
	* New Sun 1.4 JVM

	* Now installs in /usr/lib/jvm-bridge/
	* ExecuteFunction bindings now done at run-time

Haskell/Java VM Bridge allows Haskell programs access to the Java Virtual 
Machine. It comes in two parts: the 'Native' part, that abstracts away 
differences in the various Java VMs, and the 'Haskell' part that provides 
a Haskell API. The Native part is not Haskell-specific, and could 
potentially be used by other languages wishing to access the Java VM.

Features include:

* Calling of Java methods, access to fields, array-handling;

* Integration of garbage collectors;

* Reconciliation of exception models;

* Reconciliation of thread models, including 'synchronized' monitor 
support and the ability to fork Haskell actions as Java threads;

* Strong typing for Java classes and method argument lists (as tuples), 
and use of Haskell lists as arrays;

* Creation of Java classes 'on the fly' (using DefineClass and the Java 
Class File Format) that can have Haskell callback methods;

* Lifted monads which do all the necessary JNI class and method/field ID 
preloading and 'JNIEnv'-pointer variable handling for you -- these can be 
automatically generated via a tool (MakeJVMModule);

* Layered design includes lower-level IO-based interface;

* Automatic generation of modules for Java API classes;

* All relevant imports, flags and libraries etc. handled by a single GHC 
package 'javavm';

* No 'unsafe' Haskell calls or pure function FFI anywhere;

* Easy to port to new Java VMs.

This release should be 'beta' quality, but has undergone little testing.

You will need:

* An x86 machine running some form of Unix, or a Mac OS X machine;

* GHC 5.02.4 or later;

  In particular, GHC 5.02.2 and earlier will not work on Mac OS X.

* A Java VM. It's been tested only with Sun's JVM, but should (may?) work 
with a number of others.

Haddock documentation is currently blocked on a bug in Haddock ("implicit 
parameters"). Should that be fixed, you will be able to build API 
documentaion by doing "make doc".

Some simple examples have been included such as a program that shows a 
Java Frame containing an instance of a Haskell-defined subclass of Canvas 
that has a Haskell 'paint' method that draws an oval. You should be able 
to figure out most of it from that.

Haskell/JVM Bridge and source code is licensed under the GNU Lesser GPL.


Future plans:

* port to Cygwin

* use hierarchical module structure

* separate out pure (non-FFI) Haskell into a separate package

* better typing for the IO-based layer

Ashley Yakeley, Seattle WA
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