Generate .pyc from Python AST?

Question

How would I generate a .pyc file from a Python AST such that I could import the file from Python?

I've used compile to create a code object, then written the co_code attribute to a file, but when I try to import the file from Python, I get an ImportError: Bad magic number in output.pyc.

Answer 1

The solution can be adapted from the py_compile module:

import marshal
import py_compile
import time
import ast

codeobject = compile(ast.parse('print "Hello World"'), '<string>', 'exec')

with open('output.pyc', 'wb') as fc:
    fc.write('\0\0\0\0')
    py_compile.wr_long(fc, long(time.time()))
    marshal.dump(codeobject, fc)
    fc.flush()
    fc.seek(0, 0)
    fc.write(py_compile.MAGIC)

Answer 2

The compile standard function provides this function for both Python 2.x and Python 3.x. However, you will find that the AST representation between 2.x and 3.x is quite different, so be prepared for that.