Question

I’m trying to build a sort of script system in python that will allow small snippets of code to be selected and executed at runtime inside python.

Essentially I want to be able to load a small python file like

for i in Foo: #not in a function.
    print i

Where somewhere else in the program I assign what Foo will be. As if Foo served as a function argument to the entire loaded python file instead of a single function

So somewhere else

FooToPass = GetAFoo ()
TempModule = __import__ ("TheSnippit",<Somehow put {'Foo' : FooToPass} in the locals>)

Answer 1

It is considered bad style to have code with side effects at module level. If you want your module to do something, put that code in a function, make Foo a parameter of this function and call it with the desired value.

Python’s import mechanism does not allow to preinitialise a module namespace. If you want to do this anyway (which is, in my opinion, confusing and unnecessary), you have to fiddle around with details of the import mechanism. Example implementation (untested):

import imp
import sys

def my_import(module_name, globals):
    if module_name in sys.modules:
        return sys.modules[module_name]
    module = imp.new_module(module_name)
    vars(module).update(globals)
    f, module.__file__, options = imp.find_module(module_name)
    exec f.read() in vars(module)
    f.close()
    sys.modules[module_name] = module
    return module