Bad performance of simple regular expression - why??

[Manfred Nowak]

Walter Bright <newshound at digitalmars.com> wrote

> If it fails, then fallback to the original method.

It is a ridiculous business to incorporate additional algorithms 
because a current implementation is broken.

The well known chain of converting RE->NFA->DFA->minimal DFA
should handle that problem fast, because the minimal DFA for a RE of 
the form ((a?)^n a^n) for fixed n is a chain of 2n nodes, which 
corresponds to the longest acceptable input.

In this chain the first n-1 nodes are nonfinal, all others are final.
The first node is the start node.
All nodes have transitions to the next node under "a".

-manfred