Hi Ian, On Tue, Sep 7, 2010 at 20:00, Ian <hobso...@gmaiil.com> wrote:
> On 07/09/2010 11:50, Bruno Desthuilliers wrote: > > note the order of the above - log is defined before the import. > > And ? Do you think it will affect the imported module in any way ? Like, > say, magically "inject" your log function in the DelNotePrinter module ?-) > > Just that log is defined before the global log is encountered to that if > the compiler needed to set up a link at compile time it was able to do so. > > I think I see where you're going wrong -- this bit me too when I was learning Python, having come from PHP. Unlike PHP, when you import a module in Python it does *not* inherit the importing module's namespace. So the "log" function you're accessing in DelNotePrinter.py is not the one you defined above the import statement. > In Python, "global" means "module-level", and it's only necessary when you > want to rebind a module-level name from within a function or method. > > Exactly! I want to bind the name log to the function I wrote. > As Bruno pointed out, the "global" statement is only necessary if you want to "rebind" a name -- i.e. if you want to modify how an object appears to the global scope. It's not necessary if you simply want to call a function. > > I have read http://docs.python.org/reference/simple_stmts.html#globalvery > carefully and I still don't understand. > > > The statement definition makes no sense if you don't understand namespaces > and bindings: > > http://docs.python.org/reference/executionmodel.html#naming-and-binding > > Thanks for the pointer. What a truly execrable piece of writing - full of > over-long sentences and multiple subordinate clauses. It routinely uses > terms before definition, and sometimes without definition. It is > astonishingly bad. > Perhaps you could help rewrite it? I'm sure the maintainers would be very happy to get a documentation patch. > > The third sentence reads "Each occurrence of a name in the program text > refers to the *binding* of that name established in the innermost function > block containing the use." What does that mean? It appears to mean that it > is the assignment in the innermost function block that binds for all uses, > not the first, not module blocks, not class blocks and not code blocks - but > the innermost function block. That might be correct, but somehow I doubt it, > for it would mean that earlier bindings are ignored or invalidated or not > used or something - even if the inner block is not executed. > > I am not stupid and English is my mother tongue, and I have read that page > many times. The implications of the passage are still opaque to me. > > How can I call a global function placed at the top of the source. Do I > really have to move a 4 line function into its own file and import it again > and again and again? > The short answer is yes. If you have this and similar functions that you call from various modules, then it's ideal to put them in a utility module of their own. However, as imported modules are cached in Python, this isn't as expensive as you might think if you are more used to other languages. -- Rami Chowdhury "Never assume malice when stupidity will suffice." -- Hanlon's Razor 408-597-7068 (US) / 07875-841-046 (UK) / 0189-245544 (BD)
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