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Re: Non-deterministic content model
- From: Marcus Carr <firstname.lastname@example.org>
- To: Jason Chalecki <email@example.com>
- Date: Thu, 14 Jun 2001 09:05:25 +1000
Jason Chalecki wrote:
> ((a, b)*, a) essentially represents the language where the first and
> last letter is a. Additionally, if there are b's, a and b must
> alternate. So (a, (b, a)*) matches the same language and is
> deterministic, correct?
Yes, but the original model was allowed to finish with either a or b - the
final a had a question mark. To model that with your approach would result
in (a, (b, a?)*), which allows a string of b's with no intervening a's.
Either way, you've changed the model.
Marcus Carr email: firstname.lastname@example.org
Allette Systems (Australia) www: http://www.allette.com.au
"Everything should be made as simple as possible, but not simpler."