My hobbyist coding updates and releases as the mysterious "Mr. Tines"

Wednesday, 24 September 2008

Scaling the tower of Babel II

Finally, a little digital extraction. Scala from IronPython, works as expected. In file operator.scala:

package com_ravnaandtines.operator

trait Process {
 def op(x:Int, y:Int) : Int

class Multiply extends Process {
  def op(x:Int, y:Int) : Int =
   x * y

class Perform69 {
 def sixByNine(x: Process) =

Set up as in the previous post, and build using %SCALA_HOME%\bin\scalac-net.bat operator.scala to get operator.msil -- no assembly is generated at this point. Edit the .msil file as required to point at the appropriate versions of the runtime (see previous post). Then ilasm .\Operator.msil /dll /output=operator.dll. Now fire up IronPython:

>>> import clr
>>> clr.AddReference("operator.dll")
>>> from com_ravnaandtines.operator import *
>>> dir()
['Multiply', 'Perform69', 'Process', '__builtins__', '__doc__', '__name__', 'clr']
>>> m = Multiply()
>>> p69 = Perform69()
>>> p69.sixByNine(m)
>>> class Adder(Process):
...   def op(self,a,b):
...     return a+b
>>> add = Adder()
>>> p69.sixByNine(add)

So long as we get our interfaces/traits from Scala, all is fine.

In order to do the same in the JVM world, I need to have done set CLASSPATH=%CLASSPATH%;C:\\lib\scala-library.jar; and then I can do exactly as above, but without the first two lines with clr. Those I can put in a try/except, for common coding.

Note -- it is neither necessary nor sufficient to put the Scala library jar in java.class.path or python.path properties.

No comments: