1. The Purdue Compiler Construction Tool Set (PCCTS). PCCTS consists of ANother Tool for Language Recognition (ANTLR), a DFA-based Lexical analyzer Generator (DLG) and assorted other utilities designed for the construction of compilers and other language translators. ANTLR is a parser generator which generates recursive descent parsers which are easier to debug than the table driven bottom-up parsers created by YACC. It also provides support for the automatic generation of Abstract Syntax Trees (AST's). From Debian 3.0r0 APT