Re: [Jython-dev] Assigning to func_code

[Paul D. F. <pdf...@ku...>]

More on this:

Drat, it doesn't work for instance methods, producing a "readonly class or 
attribute" error in Jython 2.1. Wonder why? I don't see anything obvious 
in the Java code (lookign at 2.2 though), and I'm assuming this is using a 
PyFunction too? Funny how I can still assign a method to a regular 
function though!

So, I try it in 2.2 from CVS. And I get:
 >>> Z.foo.func_code = Q.foo.func_code
Traceback (innermost last):
   File "<console>", line 1, in ?
AttributeError: 'method' object has no attribute 'func_code'

Transcripts for each version:
==============
$ java -jar jython.jar
jython: pdf modified version from CVS
Jython 2.2a1 on java1.4.2-02 (JIT: null)
Type "copyright", "credits" or "license" for more information.
 >>> class Z:
...  def __init__(self): self.test = 10
...  def foo(self): print "foo1", self.test
...
 >>> Z().foo()
foo1 10
 >>> class Q:
...  def __init__(self): self.test = 11
...  def foo(self): print "foo2", self.test
...
 >>> Q().foo()
foo2 11
 >>> Z.foo.func_code = Q.foo.func_code
Traceback (innermost last):
   File "<console>", line 1, in ?
AttributeError: 'method' object has no attribute 'func_code'
 >>> Z
<class __main__.Z 1>
 >>> Z.foo
<unbound method Z.foo>
 >>> Z.foo.func_code
<code object foo 2, file "<console>", line 3>
 >>> Q.foo
<unbound method Q.foo>
 >>> Q.foo.func_code
<code object foo 3, file "<console>", line 3>
 >>> Z.foo.func_code = Q.foo.func_code
Traceback (innermost last):
   File "<console>", line 1, in ?
AttributeError: 'method' object has no attribute 'func_code'

========================

$ jython
Jython 2.1 on java1.4.2-02 (JIT: null)
Type "copyright", "credits" or "license" for more information.
 >>> class Z:
...   def __init__(self):
...      self.test = 10
...   def foo(self): print "foo1", self.test
...
 >>> Z().foo()
foo1 10
 >>> class Q:
...   def __init__(self):
...     self.test = 11
...   def foo(self): print "foo2", self.test
...
 >>> Q().foo()
foo2 11
 >>> Z.foo.func_code
<code object foo at 32567496, file "<console>", line 4>
 >>> Z.foo.func_code = Q.foo.func_code
Traceback (innermost last):
   File "<console>", line 1, in ?
TypeError: readonly class or attribute: func_code
 >>> Q.foo.func_code
<code object foo at 30015102, file "<console>", line 4>
 >>> Z.foo.func_code = Q.foo.func_code
Traceback (innermost last):
   File "<console>", line 1, in ?
TypeError: readonly class or attribute: func_code
 >>> def x(): pass
...
 >>> x.func_code
<code object x at 22081762, file "<console>", line 1>
 >>> x.func_code = Q.foo.func_code
 >>> x()
Traceback (innermost last):
   File "<console>", line 1, in ?
TypeError: foo() takes at least 1 argument (0 given)
 >>> x(None)
foo2Traceback (innermost last):
   File "<console>", line 1, in ?
   File "<console>", line 4, in foo
AttributeError: 'None' object has no attribute 'test'
 >>> x(Q())
  foo2 11
 >>> x(Z())
foo2 10
 >>> Q.foo.func_code
<code object foo at 30015102, file "<console>", line 4>
 >>> Q.foo.func_code = Z.foo.func_code
Traceback (innermost last):
   File "<console>", line 1, in ?
TypeError: readonly class or attribute: func_code
 >>> Q().foo.func_code = Z.foo.func_code
Traceback (innermost last):
   File "<console>", line 1, in ?
TypeError: readonly class or attribute: func_code
 >>>

==============

So, apparently this functionality has changed from Jython2.1, although it 
doesn't work as I hoped for in either version. More exploring to do.

--Paul Fernhout