Yacc itself used to be available as the default parser generator on most Unix systems, though it has since been supplanted as the default by more recent, largely compatible, programs. Yacc was originally developed in the early 1970s by Stephen C. T Corporation and written in the B programming language, but soon rewritten in C. It appeared as part of Version 3 Yacc parser generator pdf, and a full description of Yacc was published in 1975.
Its output is a shift-reduce parser in C that executes the C snippets associated with each rule as soon as the rule is recognized. Typical actions involve the construction of parse trees.
Yacc itself used to be available as the default parser generator on most Unix systems, though it has since been supplanted as the default by more recent, largely compatible, programs such as Berkeley Yacc, GNU bison, MKS Yacc and Abraxas PCYACC. Each offers slight improvements and additional features over the original Yacc, but the concept and syntax have remained the same. Yacc has also been rewritten for other languages, including OCaml, Ratfor, ML, Ada, Pascal, Java, Python, Ruby, Go and Common Lisp. Lexical analyzer generators, such as Lex or Flex are widely available.
2 standard defines the functionality and requirements for both Lex and Yacc. T Yacc have become open source. T Yacc itself because of lack of reuse restrictions and performance.
LALR parser: The underlying parsing algorithm in Yacc-generated parsers. Bison: The GNU version of Yacc.