[Python-Dev] Java-ing Python

Greg Ewing greg@cosc.canterbury.ac.nz
Fri, 12 Apr 2002 12:05:22 +1200 (NZST)

> what if I replace Python's Grammar file with a Java grammar (for
> example, the java grammar included in the ANTLR distribution). Hacked
> appropriately to map java source to the tokens defined in python's
> Grammar would in theory make python 'understand' java.

If you're planning on feeding the resulting parse tree to the existing
Python bytecode compiler, you don't stand a chance.  The compiler is
absolutely dependent on getting a particular parse tree structure, and
that structure is derived directly from the grammar.

The best you could hope for this way would be to get something which
is really Python with a few cosmetic alterations to make it look very
vaguely Java-like.  There's no way it's going to be able to handle
arbitrary real-life Java code.

To handle anything like real Java, you'll have to extensively
rework the bytecode compiler to match the new grammar. Not to
mention deciding what to do about all the semantic differences
between Python and Java.

If you really want to tackle this, go ahead, it sounds like an
interesting project -- but be aware that it will be a LOT of
work. Unless you've got an enormous amount of Java to translate,
it's going to be faster and easier to just rewrite it by hand!

Greg Ewing, Computer Science Dept, +--------------------------------------+
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