Moving from PHP to Python. Is it Possible

[Diez B. Roggisch]

>> 1) PHP does some really nasty things in how it treats globals, and you
>> will have to break yourself of those sorts of habits -- Python offers
>> much cleaner alternatives, like grouping similar functionality into
>> modules which can be imported; the import functionality in python is
>> pretty flexible.
>> Python won't pack a ton of garbage into a giant, global
>> 'dictionary' (what python calls associative arrays).  There are
>> modules (bundled of code) which you can import to handle your needs.
> 
> PHP was doing tons of nasty things. 10 years after I'm starting to understand 
> some those and still not understand most programmers point of view to GLOBALS 
> are evil. Anyhow I'm self learner plus I got heavy English limitation or 
> probably I'm too narrow minded to see right thing.
> 
> In my usage GLOBALS are too much useful to discard it. 

The problem with global variables is their scope. If you have a piece of 
code, the important thing to know is what influences it's behavior when 
being executed. Functional programs take this to the extreme and usually 
don't allow any global or otherwise shared state, so if you have a 
function that reads

a = f(x)

and you invoke it twice with the same value for x, you get the same result.

But sometimes, you need state that is preserved over time. Object 
orientied design encapsulates this in objects. Each function (method) in 
a car-object shares the cars state. But *not* the state of *all* cars, 
which global variables would.

Now when reading code, you have to juggle with all the state that 
influences it. The broader the scope (and global is the biggest one you 
can get) the harder it is to understand. And believe me, the longer a 
system exists and the older the code is you look at, the harder it is to 
understand what's happening.

> 
> Anyway, I need to save my lots and lots of config variables in dictionary style 
> global accessible location. 
> 
> Because.
> 
> In my design We got lots of plugins, and those plugins may show in multiple 
> times and multiple locations in a page.
> 
> Each plugin may have setup values to affect entire page output.
> 
> Because of this. I have to put those values in global location for future use.

No, you don't. Because of this, you can e.g. use ToscaWidgets as a 
framework for creating widgets that encapsulate code, HTML, javascript 
and CSS. And no global state is shared.

Also, I think you should *really* look into one of the available 
web-frameworks such as Django or Turbogears to learn how to write 
webapps in python - instead of shoehorning your tried & trusted PHP 
techniques that don't translate well.

Diez