Well that's because Sage has a preparser. You could as well say that because f(a) = 2 is invalid Python code, so should it be invalid Sage code, regardless of whether it's a function definition or not.
This, on the other hand, is perfectly valid Python: >>> def f(x): ... a = 1 ... def f(a): ... return a ... return f(x) ... >>> f(2) 2 >>> Your invalid Python above is invalid not because of the semantics of redefining f within f, but just the fact that vanilla Python doesn't have the "f(x) = foo" symbolic 'function' definition syntax Sage does. If there's anything wrong with defining symbolic functions inside other functions it's this, IMO: sage: a --------------------------------------------------------------------------- NameError Traceback (most recent call last) /home/fs/src/ipython/<ipython console> in <module>() NameError: name 'a' is not defined sage: def f(x): ....: p(a) = 3 ....: return "foo" ....: sage: f(2) 'foo' sage: a a sage: -Keshav ---- Join us in #sagemath on irc.freenode.net ! -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
