compiler design

i am doing my project on compilers.dis subject is new to me.i needed help in working with lex.i have downloaded the flex tool bt do not know how to use it.it would be gre开发者_StackOverflowat if i get some help

Before attempting to use tools like flex/yacc that generate scanners and parsers, I think it is important to first understand the concepts behind them. The book "Language Implementation Patterns: Create Your Own Domain-Specific and General Programming Languages" by Terrance Parr (creator of ANTLR) explains a lot of these concepts in a way easier to understand than a lot of other books / guides out there. This is also a good lex/yacc tutorial: http://epaperpress.com/lexandyacc/