py311-sly

Python implementation of the lex & yacc tools

SLY is a 100% Python implementation of the lex and yacc tools commonly used to write parsers and compilers. Parsing is based on the same LALR(1) algorithm used by many yacc tools. SLY provides very extensive error reporting and diagnostic information to assist in parser construction. The original implementation was developed for instructional purposes. As a result, the system tries to identify the most common types of errors made by novice users. SLY provides full support for empty productions, error recovery, precedence specifiers, and moderately ambiguous grammars. SLY uses various Python metaprogramming features to specify lexers and parsers. There are no generated files or extra steps involved.