On Sun, Nov 3, 2013 at 9:55 PM, Jason Friedman <jsf80...@gmail.com> wrote:
>
>> I wrote this decorator: https://gist.github.com/yasar11732/7163528
>>
> I ran it with Python 2 and thought it was neat.
> Most of my work is Python 3.
> I ran 2to3-3.3 against it and I am getting this error:
>
> $ ./simple.py
> Traceback (most recent call last):
> File "./simple.py", line 3, in <module>
> @debugger.debugging
> File "/home/jason/python/debugger.py", line 41, in debugging
> new_function_body.append(make_print_node("function %s called" %
> func.__name__))
> File "/home/jason/python/debugger.py", line 6, in make_print_node
> return ast.Print(dest=None, values=[ast.Str(s=s)], nl=True)
> AttributeError: 'module' object has no attribute 'Print'
>
> Comparing http://docs.python.org/2/library/ast.html#module-ast against
> http://docs.python.org/3.3/library/ast.html#module-ast I see that "Print"
> has indeed been removed.
Ah, that'd be because 'print' is no longer a statement. Check out this
function's disassembly:
def hello_world():
print("Hello, world!")
Python 2.7:
2 0 LOAD_CONST 1 ('Hello, world!')
3 PRINT_ITEM
4 PRINT_NEWLINE
5 LOAD_CONST 0 (None)
8 RETURN_VALUE
Python 3.3:
2 0 LOAD_GLOBAL 0 (print)
3 LOAD_CONST 1 ('Hello, world!')
6 CALL_FUNCTION 1 (1 positional, 0 keyword pair)
9 POP_TOP
10 LOAD_CONST 0 (None)
13 RETURN_VALUE
As print is now a function, you're going to need to construct a
function call element instead of a special 'print' node. I don't know
how to do that as I'm not an AST expert, but hopefully you can work it
out from there?
If you need it to be cross-version, you could probably use
sys.stdout.write explicitly (not forgetting to add a newline, which
print does and write - obviously - doesn't). Or just demand that "from
__future__ import print_function" be used, which will make 2.7 like
3.3.
ChrisA
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