I was not talking in practice, in was meaning "in theory". In theory, the fact that most of the language is specified via code helps avoiding incompatible implementations. In practice, that's another problem, but it's only the beginning...
Where pg fails.... --warning-blatant-self-promotion-- Anarki! Whee!
Hmm. Probably need a "Report on Anarki" as a spec of the standard Anarki, particularly 'call* and 'defcall, which may very well be the most important extension in Anarki.