string interpolation (was: Newbie can't figure out documentation practices)

[Iwan van der Kleyn]

Fernando Perez wrote:
> My point in all of this is that python, while overall incredibly clean in
> its design, lacks an easy way of accessing object member data for string
> interpolation. 

By design yes, in practice no. In the CookBook you can find a solution 
(or hack if your prefer). Instead of using locals() you use a custom 
class which accesses the 'namespace' of the caller through the 
sys._getframe() function.

Personally I would argue that Python's powerfull introspection 
facilities often negates the call for Yet Another Feature to be included 
in Python :-)

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66018
and
http://www.python.org/doc/current/lib/module-sys.html

# __________________________________________
#example
import sys

class Eval:
     globals = globals()
     def __getitem__(self, key):
         self.locals = sys._getframe(1).f_locals
         key = key % self
         return eval(key, self.globals, self.locals)

class Test:
     def go(self, b):
         c = 'locals'
         self.d = 'object attributes'
         return 'Eval evaluates %(a)s, %(b)s, %(c)s and even %(self.d)s' 
% Eval()

a = 'globals'
print Test().go('parameters')