The "Spellserver": A Generic Remote-Code-Execution Host

A "Spellserver" is my name for a very generic server design: one in which the server-side code is provided by the clients (but somehow constrained by the server owner). I've been exploring ways to achieve E-like delegation and attenuation-by-code, in which I can write a program to enforce my restrictions (rather than pre-programming the server with all conceivable ones). E provides this quite elegantly, but depends upon a number of unusual platform details, many of which have not actually been implemented yet. I'm looking for a way to achieve similar goals but in a familiar language like Javascript, and invoked via plain HTTP. moreā€¦