I read it through and used it frequently as I
was doing a project. Overall it is informative
enough to let me finish my project smoothly.

Plus :

. Mentions a lot of variants. Good coverage.
. SQL parser is particularly helpful to me as
I am writing a SQL-like parser. It gave me
a kick start.

Minus :

. Lacks a intuitive explanation of the interfacing
between lex and yacc. It took me a quite while
to figure out all the details and the underlying
mechanisms.

. It would be much better to provide some insight
into the design of lex/yacc programs. For
example :
1. parsed information can be carried forward
through either static global variable or
yylval struct. (Once I realized this,
my project overall design become clear.)
2. How to interface with C++ program?
3. Where actions happen? Along the parsing
or just carrying the information during
parsing and do the actions in the end?

. Sample code still has bugs, - like everyone
else. :-)