The aforementioned Dragon book is the classic compiler book, but since you mention online resources --- one book you might consider is: Parsing Techniques -- A Practical Guide (Dick Grune and Ceriel J.H. Jacobs, 1990) Not a "compiler" book per se, but quite a bit of general and specific parsing theory in a relatively easy to swallow presentation. Published in 1990, it went out of print and the authors regained the copyright and have made it available in postscript or pdf formats at this site