You've got a syntax error somewhere in your code. It could be around line 15. Good luck finding it.

This document explains how to construct a compiler using lex and yacc. Lex and yacc are tools used to generate lexical analyzers and parsers. I assume you can program in C, and understand data structures such as linked-lists and trees.

re2c is a tool for writing very fast and very flexible scanners. Unlike any other such tool, re2c focuses on generating high efficient code for regular expression matching.