Fun with Python scopes

scopes.py

global_var = 42

def outer_func():
    outer_var = 21
    un_used_outer_var = 16
    def inner_func():
        inner_var = 7
        def inner_inner_func():
            inner_inner_var = 3
            # note: the outer_var must be explicitly referenced, otherwise it won't
            # be added to the list of co_freevars. Notice that 'un_used_outer_var'
            # doesn't get shown anywhere.
            inner_var
            outer_var
            # note, though, that the global_var is *not* added to the freevars
            global_var
            print "inner inner locals:", locals()
        return inner_inner_func
    inner_inner_func = inner_func()
    inner_inner_func()
    print "inner inner freevars:", dict(zip(
        inner_inner_func.func_code.co_freevars,
        [ c.cell_contents for c in inner_inner_func.func_closure ],
    ))
    print "inner freevars:", dict(zip(
        inner_func.func_code.co_freevars,
        [ c.cell_contents for c in inner_func.func_closure ],
    ))

outer_func()

"""
Result:
inner inner locals: {'inner_var': 7, 'inner_inner_var': 3, 'outer_var': 16}
inner inner freevars: {'inner_var': 7, 'outer_var': 16}
inner freevars: {'outer_var': 16}
"""