Am 29.08.2012 17:04, schrieb Franck Ditter:
I use Python 3.2.3 + Idle.
Is it possible to program test(e) which takes
an expression e and whose execution produces
at the toplevel an echo of e and the effects
and result of its evaluation ?
Yes, the key to this is using a lambda expression.
# file foo.py
def foo(x) :
print('x =',x)
return x+1
test(foo(5))
def test(exp):
global print
print_saved = print
print = my_print
res = exp()
print = print_saved
return res
test(lambda: foo(5))
The idea is to run the callable expression inside a modified
environment, in the sketch above it intercepts the calles to print()
using a separate my_print() function. Note that the calling syntax is
slightly different than the one you would have wanted, don't know if
that is important.
Things I'll leave to you:
- exception handling
- exception forwarding
- intercepting other environment accesses
- putting all that into a context manager :)
Good luck!
Uli
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