properties vs. eval()

2005-05-04 Thread Bob Rogers 
Given this class:

class C(object):
def set_x(self, x):
self._x = x

def get_x(self):
return self._x

x = property(get_x, set_x)


This use of compile() and eval() works as I expected it to:

c = C()
c.x = 5000
n = '\'five thousand\''
code = compile('c.x = ' + n, '', 'exec')
print 'before ', c.x
eval(code)
print 'after  ', c.x

But this, using eval() without compile(), does not:

c = C()
c.x = 5000
n = '\'five thousand\''
print 'before ', c.x
eval('c.x = ' + n)
print 'after  ', c.x

It gives:

before  5000
Traceback (most recent call last):
  File "./r.py", line 16, in ?
eval('c.x = ' + n)
  File "", line 1
c.x = 'five thousand'
^
SyntaxError: invalid syntax

Could someone please explain just what is going on here, and whether it
is possible to dispense with the compile step and use eval() alone
while setting a property?

Thanks.

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Re: properties vs. eval()

2005-05-05 Thread Bob Rogers 
So you're saying you don't know the answer?  The question wasn't
"should I use setattr?"

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