PyWart: Module access syntax
steve+comp.lang.python at pearwood.info
Mon Jan 14 18:34:56 CET 2013
On Sun, 13 Jan 2013 21:22:57 -0800, Rick Johnson wrote:
> On Saturday, January 12, 2013 12:45:03 AM UTC-6, Steven D'Aprano wrote:
>> On Fri, 11 Jan 2013 20:34:20 -0800, Rick Johnson wrote:
>> > [...]
>> So what do you do for, say, os.path? According to the first rule, you
>> must write it as os:path because path is a module; according to the
>> second rule, you must write it as os.path because path is a member of
>> os. So which rule wins?
> Since "path" is an identifier in the module "os" that points to a system
> specific module (which is loaded at run-time), you would access os.path
> just as you do today; using the dot. No changes here. Next!
Here you say that os.path will not change. But later in your post, you
> the programmer will need to be sure he places a colon
> between modules. Which means a programmer will need to know which path
> members are modules and which are objects
Since both os and path are modules, you here say that they need a colon
between them. This contradicts the above when you say the syntax for
os.path won't change.
If even you don't understand your own proposal, how do you expect anyone
else to understand it?
Perhaps you should start by explaining, unambiguously and IN FULL, under
what circumstances the programmer will need to use your : syntax.
os.path or os:path
json.scanner or json:scanner
> I said it before and i'll say it again: If you don't know if your calls
> are accessing module space or object space (be it instanced object or
> static object), then you are sadly informed
"Sadly informed"? Dr Freud called, he wants his slip back.
Modules are objects, and there is no difference between module space and
object space, except that Python provides a convenience syntax for
members of the current module. Modules are instances of a class, just
like ints, strings, lists, and everything else.
py> from types import ModuleType
py> type(ModuleType) is type(int)
py> hasattr(os, '__dict__')
> Wait, "classes" are NOT objects.
They certainly are. Classes are created at runtime, they have a type --
the class of a class is the metaclass. You can even customize class
behaviour with metaclass programming.
Perhaps you are thinking about some other language, like Java, which
fails to have first-class classes (pun intended).
More information about the Python-list