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Jython script to compile jython scripts to java class files

Fri 18 June 2010

Jython, the python implementation in Java, is one of the most amazing things i have come across in quite some time, the environment is a seamless fusion of both the languages.

Playing around with it since yesterday, from what i have noticed, the jythonc compiler is missing in 2.5.x version of jython. But on doing a quick search i found a java based jython compiler scripts ( here and here ). Also there don't seem to be any jython compiler scripts in jython, perhaps i maybe looking at wrong place. So i wrote up a quick script which tries to do that.

Author:Kalyan (18-Jun-10)
Usage: $jython jcompile.py
from java.io import *
import _py_compile
import imp as pyimp
import org.python.core.imp as jimp
import os.path
import sys
#Show info
def jcompile_usage():
    print "Usage $:jython jcompile.py"
    print "file.py gets compiled to file$py.class"
#Compile .py to .class
def jcompile_compile( fname ):
    #java file object
    jfile = File( fname )
    #Get module name
    mname = _py_compile.getModuleName( jfile )
    #Compile and get bytes
    bytes = jimp.compileSource( mname, jfile )
    #Dump bytecode into a file
    jimp.cacheCompiledSource( os.path.abspath( fname ), os.path.abspath( "./" + mname + "$py.class" ), bytes )
if( len(sys.argv) != 2 ):
    jcompile_usage();   #insufficient arguments
    sys.exit(0)         #exit
if( os.path.exists( sys.argv[1] ) ):
    print "compiling %s" % sys.argv[1]
    jcompile_compile( sys.argv[1] )
    print "Given file doesn't exist"

The code is a loose translation of the java code. The only catch is, there are two "imp" important internals libraries, org.python.modules.imp and org.python.core.imp, former the python implementation and the later one being the java python implementation.

Usage : to compile
kalyanc$ jython jcompilec.py foo.py
compiling foo.py

at this point foo$py.class is created

Usage : To execute
kalyanc$ java -classpath .:/Library/Jython/2.5.1/jython.jar foo\$py
foo bar