RedParse is a ruby parser written in pure ruby. Instead of YACC or ANTLR, it's parse tool is a home-brewed "compiler-interpreter". (The tool is LALR(1)-equivalent and the 'parse language' is pretty nice, even in it's current crude form.) My intent is to have a completely correct parser for ruby, in 100% ruby. Currently, RedParse can parse all known ruby 1.8 constructions correctly. There might be some problems with unparsing or otherwise working with texts in a character set other than ascii. Some of the new ruby 1.9 constructions are supported in 1.9 mode. For more details on known problems, see below.