A colleague who had been worried about one of her star students who had been missing from class for a couple of weeks came into my office. “She committed suicide yesterday.” She needed to talk through it. She told me that she and two other professors had gone to the Student Services people a few days earlier—on a weekend—concerned about the student. She told me about all the ways they had tried to get to the bottom of what was going on in the days leading up to it.

This short article is for those students, programmers, and computer scientists who already have a basic idea of what a parser is and does but who want to know what that mysterious reference to “IELR(1)” means in the Bison parser generator manual. The IELR(1) Parsing Algorithm The IELR(1) parsing algorithm was developed in 2008 by Joel E. Denny as part of his Ph.D. research under the supervision of Brian A. Malloy at Clemson University.