textproc/peg 0.1.19_1 DragonFly

peg and leg are tools for generating recursive-descent parsers: programs that perform pattern matching on text. They process a Parsing Expression Grammar (PEG) [Ford 2004] to produce a program that recognises legal sentences of that grammar. peg processes PEGs written using the original syntax described by Ford; leg processes PEGs written using slightly different syntax and conventions that are intended to make it an attractive replacement for parsers built with lex and yacc. Unlike lex and yacc, peg and leg support unlimited backtracking, provide ordered choice as a means for disambiguation, and can combine scanning (lexical analysis) and parsing (syntactic analysis) into a single activity.

[Ford 2004] Bryan Ford, Parsing Expression Grammars: A Recognition-Based Syntactic Foundation. ACM SIGPLAN Symposium on Principles of Programming Languages (POPL), 2004.