Programming language parsers, including LL(1), LR(0), LR(1), SLR(1), and LALR(1).
Obligatory BadgeFest:
Much of the code in this library was based on or inspired by the book 'Crafting a Compiler with C', by Charles N. Fischer and Richard J. LeBlanc, Jr., 1991, Benjamin/Cummings, ISBN 0-8053-2166-7.
This was the textbook for the course CS 444 (Compiler Construction) at the University of Waterloo, Ontario, Canada, which I took in January-April 1994.