## Regular Expression Matching: the Virtual Machine Approach

From: andrew cooke <andrew@...>

Date: Thu, 10 Dec 2009 18:20:00 -0300

This is a good summary of how to implement regexps.  It differs from
LEPL in that it doesn't compile to a state machine, but instead uses a
VM.  Perhaps as a result it wasn't clear to me what the difference was
between DFA and NFAs.  However, the ease with which it can be extended
illustrates the advantage of the approach (perhaps at a cost in
efficiency?).

http://swtch.com/~rsc/regexp/regexp2.html

Andrew