A more complex example - looking for patterns in DNA sequences.

This example derived from undergraduate project work by Julia Fischer
at the University of Durham. Some of the grammar is based on the ones
developed by Siu-wai Leung, Chris Mellish, and Dave Robertson at the
University of Edinburgh.  (Contact Paul Callaghan for details, and
see the accompanying paper.)

Files 1-600.dna and 1-1200.dna contain 600 (1200) bases from the sequence
for E. coli. The first sequence parses in a few minutes, the second takes
a bit longer. 

There are issues about how to efficiently skip over "noise" in the data.
This would make the parser faster. 

Use "make run" to parse the 1-1200.dna sequence - it should take under 15 
seconds