The language must allow easy access to external objects from other systems, written using any semantics or syntax. Integration is needed to allow soft and efficient upgrading of existing systems toward the Tunes project, and communication with the world external to the Tunes system. Partial evaluation Evaluation is done as early as information and resources allow. Function calls, message passing et al. can be dynamically compiled or inlined. When a generic function is called with specific but incomplete parameters, it may get specialized and optimized accordingly.
Partial evaluation is needed because it involves such performance improvements.
Persistence Object automatically persist together with the system. There is no need to explicitly convert objects to and from unsafe persistent binary or ascii files. This is a language feature, as it greatly affects the language's standard library and programming habits. Nice Human interface Syntax is purely for human convenience. LISP sucks because it forgot that simple statement.