(eval val (? env-mode 'fresh))
  val: any type
  env-mode: a sym (optional)
  returns any type

Evaluates a value as a form.

See the Evaluation chapter of the Reference Manual for the full details.

env-mode must be one of:

• fresh, which causes evaluation to occur in a new, empty lexical scope.

• copied, which causes evaluation to inherit the lexical scope of the macro which is currently being expanded, if any. This currently has no effect except for preserving local macro definitions.