1POSIX regex snarfed from Doug McIlroy's C++.  Converted to C by Glenn
2Fowler.  *'d features have been added to Doug's original code.  testre
3should compile with other regex implementations, but you may need to
4run with -c to catch non-terminating loops and memory faults.
5
6FEATURE			BRE		ERE		ARE
7-------			---		---		---
8negation		NO		expr \!		expr !
9conjunction		NO		expr \& expr	expr & expr
10NULL subgroups		YES		NO		YES
11word boundaries*	\< expr \>	\< expr \>	< expr >
12minimal match*		NO		REG_MINIMAL	REG_MINIMAL
13shell patterns*		REG_SHELL	NO		NO
14ksh patterns*		NO		NO		REG_SHELL
15