Python compared to other language

[Gabriel Genellina]

En Sat, 19 May 2007 03:24:15 -0300, walterbyrd <walterbyrd at iname.com>  
escribió:

> My guess is that some of the C code used to develop Python is the same
> between the different Python distros, but much of the code is unique
> to the particular platform. If that is the case, then the C code may
> not be very portable.

Well, your guess was wrong. The core CPython code is the same on all  
platforms; of course it uses #define/#ifdef/etc. where appropiate, but  
it's not a mess, and not so much code is conditionally compiled.
The Python developers take special care on portability - the C language  
itself (C89 is currently used) is pretty standard, but you have to be  
careful on how you write your code.

> But, I can often take the same python code, and run it on MacOS,
> Linux, FreeBSD, and Windows. Often I can do this even if the app has a
> gui interface.

Because someone has taken out all the differences, so you don't have to  
struggle with them yourself. GUI toolkits: some libraries "draw" the whole  
thing and manage all the user interaction themselves so they're basically  
portable but never have the native "look&feel" (tcl/tk); other rely on the  
native buttons and controls for each platform, but providing a homogeneous  
view for the programmer (wxWidgets). Anyway, they work across platforms  
because "someone" has already worked on the differences for you - using C.  
Both menctioned libraries are written in C (wx in C++), and Python  
provides a convenient wrapper for them.
Even on the Python side, some libraries do one thing or another depending  
on the platform (cf: subprocess). The good thing is that *you* as a  
developer, don't have to worry about the differences; many are managed by  
Python itself internally, and many are worked on by other people on top of  
this. webbrowser.open('your favourite url') "just works" and does "the  
right thing" because of these efforts.

-- 
Gabriel Genellina