[Tutor] question 1

[Danny Yoo]

On Sat, Sep 20, 2014 at 3:20 PM, Clayton Kirkwood <crk at godblessthe.us> wrote:
> I’m ramping slowly unfortunately. How does one go about knowing which module
> to import to make certain functions work? I have a read() that fails because
> there is no definition for it.

Specific details may help here.  Can you tell us more?  What are you
trying to do?  If you are seeing error messages, please copy exact
error message content and present it.  Error messages have more than
one bit of information: they usually encode some information that
folks here can try to interpret.


> Secondarily, why can you import a module without it importing all of its
> daughters?

The act of importing a module is "recursive": if you import a module,
and that module itself has import statements, then Python will do the
import of the child modules too.  And so forth.

(You might imagine a system where the "main" module must do all this
linkage by itself, rather than do this recursive walk.  And there are
systems that do work like this!  See:
https://talks.golang.org/2012/splash.article for Rob Pike's discussion
on the Plan 9 compiler, which worked this way.

But Python does not do this.)



> And why do you have to use a ‘for in to import submodule’, why
> not ’import module.sub’?

If I'm not mistaken, you _can_ do this.  Can you point us to a source
where it says you can't?

(There are particular style guidelines from certain organizations that
prohibit this kind of import, but that prohibition is by convention.
That is, it's not because the language disallows it, but because it
doesn't fit with the house coding style.)


> Lastly, in some tutorials and else-sourced docs certain lines have a ‘;’ at
> the end. This seems to be most often with ‘opens’ and ‘fopen’ kind of calls.

Huh.  Can you point to a reference?  Note that third-party
documentation (and official documentation!) might be buggy or weird.
:P  If you can point us to an example, maybe one of us can investigate
what's going on there.