That is a good point -- any existing ocde (Or new code that doesn't support keywords) would raise an Error -- though it would be a (TypeError, rather than a SyntaxError) if no index were passed in. So why not allow it?

This does require some thought about backward compatibility -- as passing anything other than a single index is now a SyntaxError, most code in teh wild will not be set up to handle the run time TypeError that might now arise.

As "proper" exception handling should be close to the operation, and catch specific Exceptions, most case will probably be fine. But not all. For example, there might be code in the wild that does

try:

    a_function(something)

except TypeError:

    do_something

And there is something in a_function that uses indexing -- someone messes with that code, and puts something new in an index that used to be a SyntaxError and is now a TypeError -- in the past, that wouldn't have even run, but now it will, and the problem might not be caught in tests because the TypeError is being handled.

Given that this would be a change from a compile time error to a runtime error, there is no code that used to work that will break, but it would be easier to write broken code in certain situations -- maybe not a huge deal, but worth thinking about.

-CHB