Peg parsing (otherwise known as understandable parsing, or parsing for humans) is how an uninitiated would go about parsing. Packrat or recursive descent are other names.
While recursive descent is proven not to be very fast, it is nevertheless used by such prominent projects as llvm (to parse c and c++), because it makes it possible to understand, and thus debug and maintain a parser with relative ease.
Citrus's uniqueness is in the way it combines the power of ruby to generate code at runtime with the ease of peg parsing. The grammar (to build grammars) is not unlike ruby itself and easily understood.
Thanks to the atom folks for writing the converter :-)
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.