Bruce wrote:
> There are lots of books about Lex and Yacc; I don't know of any extensive
> material on-line. The O'Reilly book, titled simply _lex & yacc_ (Levine,
> Mason & Brown 1992, ISBN 1-56592-000-7), is quite good.

And if you want to learn about writing compilers in general, I recommend
your choice of:

Modern Compiler Implementation in Java (the Red Tiger book) ISBN: 0521583888
Modern Compiler Implementation in ML (the Blue Tiger book) ISBN: 0521582741
Modern Compiler Implementation in C (the Green Tiger book) ISBN: 052158390X

all by Andrew W. Appel (probably no relation).

   http://www1.clbooks.com/asp/bookinfo/bookinfo.asp?theisbn=0521583888

These are intended to be used as textbooks in a compiler construction
course, so you probably need to be really interested in compilers to
enjoy them.

The books are quite up to date and describe modern optimization techniques
and code generation for RISC type architectures.

G.