[EMAIL PROTECTED] wrote:
> As a bit of a [python] newbie myself, the proper procedure for forward > declaring things has so far evaded me as well. > > Is there a "right" way to do this in python? : > ... > > def f1( i ): > if( i < 20 ): return f2(i) > else: return 0 > > def f2( i ): > if( i > 20 ): return f1(i) > else: return 0 This code will work just fine. The trick to remember, is that the def statement is an executable statement. The def statement for any function must be run by the interpreter, before the function can be called. But the interpreter doesn't look up names until runtime, so you can use the *name* of the function before you define it -- it's all dependent on the order that the interpreter processes things. In the code above, when this file is run/imported, the interpreter will read through this, see the def statements, and create two function objects. Later, when you actually call f1(5), the interpreter steps throught the body of f1(), sees that the argument passes the if-test, then sees the name f2. At this point, the interpreter does a name-lookup to find what f2 is bound to. If the interpreter hadn't already seen 'def f2(i): ...', then we'd get the NameError now. In this case, it sees "oh, yes, I have this function that's named f2..." and proceeds to call the function. Hope this makes things clearer... :) Jeff Shannon Technician/Programmer Credit International _______________________________________________ ActivePython mailing list [EMAIL PROTECTED] To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
