76 karma · joined July 30, 2012
As you can see, the library is quite advanced.
Many people asked for yaml support in composer, and it was shot down. Here's why: Once you start supporting many formats you lose interoperability, as any tooling now needs to support all formats. That is the main reason why composer will not support sexpr.
EDIT: It does not expose a REPL though, which I suppose is what you meant?
Custom autoloading scheme instead of PSR-0? Classname.inc.php, seriously? Moving on, dynamic variables are a terrible unfeature that should be avoided. References usually cause more harm than good and should be avoided as well. And finally, a class which is named with a redundant "Class" suffix, containing only static members, aka class-oriented programming.