Records and lambda abstractions can be added independently.
Concepts are orthogonal to each other and to core language.
Orthogonality of new construction:
Semantics of original constructs unchanged.
If new construction uses component phrases of original language, the
semantics of new construction is defined uniformly with respect to the
component phrases (no
special cases).
Consequences:
Typing rules and semantic equations can be added without affecting
existing language.
