UNIX time-sharing system: Language development tools

The development of new programs on the UNIX∗ system is facilitated by tools for language design and implementation. These are frequently program generators, compiling into C, which provide advanced algorithms in a convenient form, while not restraining the user to a preconceived set of jobs. Two of the most important such tools are Yacc, a generator of LALR(1) parsers, and Lex, a generator of regular expression recognizers using deterministic finite automata. They have been used in a wide variety of applications, including compilers, desk calculators, typesetting languages, and pattern processors.