Lex & YACC
 

Hi,
Could any one give me a link to a comprehensive tutorial on lex and yacc. I'm having problems understanding about YYSTYPE , yylval etc. and how to link lex and yacc files so on.

Try this page. Download the pdf file.
http://www.epaperpress.com/lexandyacc/

Thanx. That was of some help.

yylval is a global variable of type YYSTYPE.
since all the grammar variables use it for storing/passing their symantic values, it should be declared as a union (or a struct).
typedef YYSTYPE some_struct_or_union;
the problem with structs, is that they soon get bloated if you have a lot of variables...