import's recursion

[_rui_]

Thank you very much for the perfectly explanation!

Duncan Booth <duncan at NOSPAMrcp.co.uk> wrote in message news:<Xns92DC74E1263Bduncanrcpcouk at 127.0.0.1>...
> mailspamforme at yahoo.com (_rui_) wrote in 
> news:2d9b77f4.0212052022.405d2813 at posting.google.com:
> 
> > hi, list!
> > Tell me please, why recursion is absent?
> > 
> > 
> > foo.py
> > ~~~~~~
> > import foo
> > 
> 
> This is what happens:
> 
> You run the script foo.py, this creates a module called '__main__',
> compiles the code into it, executes the code.
> 
> The code in module __main__ executes 'import foo':
>    Looks in sys.modules for a module called foo.
>    There isn't one so:
>       Finds foo.py
>       Compiles foo.py into foo.pyc
>       Creates a new module 'foo' containing the foo code.
>       Stores a reference to module foo in sys.modules
>       Starts to execute module 'foo'.
>       The code in module foo executes 'import foo':
>          Looks in sys.modules for a module called foo.
>          Finds one and returns it:
>             Sets the variable foo.foo to module foo
>       Module foo has finished executing.
>    __main__.foo is set to module foo
> 
> In short imports aren't recursive because attempting to import a module 
> that is partly imported gives you a reference to the module but doesn't 
> attempt to reexecute the code it contains. This means you may get a 
> reference to a module that doesn't yet contain any functions or classes, 
> but that isn't a problem so long as you dont attempt to reference them 
> until later when all the imports have completed.