What's the difference between running a script under command box and interpreter?

[jfong at ms4.hinet.net]

Peter J. Holzer於 2019年11月4日星期一 UTC+8上午3時59分36秒寫道：
> On 2019-11-01 04:24:38 -0700, jfong at ms4.hinet.net wrote:
> > > The globals are your current module's namespace, and functions defines 
> > > in a module are bound to that module's namespace.
> > > 
> > > Strip your test.py back. A lot. Try this:
> > > 
> > >     def main():
> > >       print(rule)
> > > 
> > > Now, let's use that:
> > > 
> > >     Python 3.7.4 (default, Sep 28 2019, 13:34:38)
> > >     [Clang 8.0.0 (clang-800.0.42.1)] on darwin
> > >     Type "help", "copyright", "credits" or "license" for more information.
> > >     >>> import test
> > >     >>> test.main()
> > >     Traceback (most recent call last):
> > >       File "<stdin>", line 1, in <module>
> > >       File "/Users/cameron/tmp/d1/test.py", line 2, in main
> > >         print(rule)
> > >     NameError: name 'rule' is not defined
> 
> [Explanation snipped]
> 
> > I didn't noticed that the interpreter has its own globals. Thanks for reminding.
> 
> It's not really "the interpreter" (I think you mean the REPL) which has
> it's own globals. Every module/file has its own globals.
> 
> The same thing happens non-interactively:
> 
> % cat test.py 
> def main():
>     print(rule)
> 
> % cat foo.py 
> #!/usr/bin/python3
> 
> from test import *
> 
> rule = 42
> main()
> 
> % ./foo.py 
> Traceback (most recent call last):
>   File "./foo.py", line 6, in <module>
>     main()
>   File "/home/hjp/tmp/test.py", line 2, in main
>     print(rule)
> NameError: name 'rule' is not defined
> 
> The "rule" identifier in main() refers to a "rule" variable in the
> module test. If you set a variable "rule" somewhere else (in foo.py or
> the REPL, ...), that has no effect. How should python know that you want
> to set the rule variable in the test module?
> 
> 	hp
> 
> -- 
>    _  | Peter J. Holzer    | Story must make more sense than reality.
> |_|_) |                    |
> | |   | hjp at hjp.at         |    -- Charles Stross, "Creative writing
> __/   | http://www.hjp.at/ |       challenge!"


I innocently thought that when import module through "from test import *", I am working on test's globals under REPL. I didn't noticed the REPL has its own globals.

>>> How should python know that you want to set the rule variable in the test module?

My 'wrong' answer will be, at the time I raised my question, that when import two different modules either has 'rule' variable, REPL will see the second imported one. No kidding:-) 

--Jach