Here I note that while JRuby and IronRuby ported parse.y, CPython, Jython, and IronPython use totally different parsing (CPython rolls its own parser generator,

Here I note that while JRuby and IronRuby ported parse.y, CPython, Jython, and IronPython use totally different parsing (CPython rolls its own parser generator, Jython uses ANTLR, IronPython does handwritten recursive descent parsing) but are still comatible with each other.