Stanford University: Keith Schwarz's "Lexical Analysis"

Read from page 3 to the end, including Scanner Implementation 1 and 2, and the FORTRAN I Case Study.

Click http://web.archive.org/web/20160310180534/http://www.keithschwarz.com/cs143/WWW/sum2011/handouts/030_Lexical_Analysis.pdf link to open resource.