On Mon, May 20, 2013 at 11:26 PM, Frank Millman <fr...@chagford.com> wrote:
> 0 - for the first entry in the list, the word 'check' (a placeholder - it is
> discarded at evaluation time), for any subsequent entries the word 'and' or
> 'or'.
>
> 1 - left bracket - either '(' or ''.
>
> 5 - right bracket - either ')' or ''.I think what you have is safe, but extremely complicated to work with. Six separate pieces, and things have to be in the right slots... I think you've spent too many "complexity points" on the above three components, and you're getting too little return for them. What happens if the nesting is mucked up? Could get verrry messy to check. Combining multiple conditions with a mixture of ands and ors is a nightmare to try to explain (unless you just point to the Python docs, which IMO costs you even more complexity points); the only safe option is to parenthesize everything. The system I pushed for at work (which was finally approved and implemented a few months ago) is more or less this: conditions are grouped together into blocks; for each group, you can choose whether it's "all" or "any" (aka and/or), and you choose whether the overall result is all-groups or any-group. That still costs a few complexity points (and, btw, our *actual* implementation is a bit more complicated than that, but I think we could cut it down to what I just described here without loss of functionality), but it gives the bulk of what people will actually want without the complexities of point-and-click code. The downside of that sort of system is that it requires a two-level tree. On the flip side, that's often how people will be thinking about their conditions anyway (eg using a pair of conditions ">" and "<" to implement a range check - conceptually it's a single check), so that won't cost too much. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
