A Theory of Discrete Patterns and Their Implementation in SNOBOL4
The notion of a discrete pattern is formalized
and certain properties deduced.  A pattern is 
shown to be a generalization of a formal language. 
Algorithms for implementing the kinds of patterns 
in SNOBOL4 are given.  The general approach is to create,
in-so-far as possible, a bottom-up parse from 
a top-down specification.
CACM February, 1973
Gimpel, J. F.
