self

holger krekel pyth at devel.trillke.net
Fri Jun 7 02:30:10 CEST 2002


Vojin Jovanovic wrote:
> I don't think you tested your code, because I can't get the output you
> specified.  In fact it seems that you broke your own code.

of course i tested it! Do you really think i am making up
results which can be proven wrong in ten seconds? Why such a
harsh reaction without bothering to correct the obvious 'typo'?
I don't actually know what went wrong while pasting the 
code ('Namerror' instead of 'NameError'). 

Anyway, here is the paste-typo-corrected version:

class Evaluator:
    def __init__(self, eqs={}):
        self.__dict__['equations']=eqs
    def __getattr__(self, name):
        value = self.equations[name]
        if type(value)!=str:
            return value   # if it's not a string, just give it back
        scope={}
        while 1:
            try:
                return eval(value, scope)
            except NameError, n:
                var=str(n).split("'")[1]
                scope[var]=getattr(self, var)
    def __setattr__(self, name, value):
        self.equations[name]=value

class Berta:
    a=5

>>> e=Evaluator({'a':3})
>>> e.berta=Berta()
>>> e.g='berta.a*a'
>>> e.g
15

regards,

    holger





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