PyPy Translation error

Question

I hope this is the right place for this question. I'm trying to write a simple JIT-enabled interpreter. However, I'm hitting a odd error when it comes to translation. I've copied the JavaScript example parser almost verbatim, but here's my issues:

First of all, here's parser (almost 100% like the JS example):

from pypy.rlib.parsing.ebnfparse import parse_ebnf, make_parse_function
from pypy.rlib.parsing.parsing import ParseError, Rule
import py
import sys

GFILE = py.magic.autopath().dirpath().join("grammar.txt")

try:
       t = GFILE.read(mode="U")
       regexs, rules, ToAST = parse_ebnf(t)
except ParseError, e:
       print e.nice_error_message(filename=str(GFILE), source=t)
       raise

parsef = make_parse_function(regexs, rules, eof=True)

def parse(code):
       t = parsef(code)
       return ToAST().transform(t)

and my grammar:

STRING: "\\"[^\\\\"]*\\"";
SYMBOL: "[A-Za-z+-_*<>]+";
KEYWORD: ":[A-Za-z+-_*<>]+";
INTEGER: "\-?([0-9]+)";
DECIMAL: "\-?(0|[1-9][0-9]*)(\.[0-9]+)?([eE][\+\-]?[0-9]+)?";
IGNORE: " |\n|\t|,";
value: <KEYWORD> | <SYMBOL> | <STRING> | <DECIMAL> | <INTEGER> |
<hash> | <vector> | <sexps>;
hash: ["{"] (entry [","])* entry ["}"];
vector: ["["] value* ["]"];
entry: STRING [":"] value;
sexps: ["("] value+ [")"];

I'm doing the following to compile the code to c:

import parse
t = Translation(parse.parse)
t.annotate([str])
t.rtype()
t.compile_c()
>>>
<---snip---->
File "/home/tbaldridge/pypy/pypy/translator/c/genc.py", line 339, in
getentrypointptr
   self._wrapper = new_wrapper(self.entrypoint, self.translator)
 File "/home/tbaldridge/pypy/pypy/translator/llsupport/wrapper.py",
line 57, in new_wrapper
   r_to = pyobj_repr)
 File "/home/tbaldridge/pypy/pypy/rpython/rtyper.py", line 931, in convertvar
   (r_from, r_to))
pypy.rpython.error.TyperError: don't know how to convert from
<InstanceRepr for pypy.rlib.parsing.tree.Node> to <PyObjRepr *
PyObject>

What am I missing? This seemed so straight-forward....

Answer 1

Your function returns a RPython-level AST node, which is a C structure after translation. The translator does not know how to represent this in the Python interpreter, to return the result when the function is called.

in C, a main() function can only return an integer. In pypy, the interactive translator can pass and return strings, ints, floats and tuples. You should process the ast nodes and return basic types.

Answer 2

This is a very specific pypy-related question and you're more likely to get answers on #pypy on irc.freenode.net or asking on pypy-dev.

That said, you should not use interactive translation for that (among other things it has insane defaults). Instead you should write a target (look into translator/goal/targetnopstandalone.py for an example) and use translate.py to compile it.