1. BOX the int argument in Bsta, Belem and Barray (x86).
2. Implement eta-conversion construct.
3. Implement lazy construct.
4. Make the expression in the scope expression optional everywhere.
4. Implement better scoping in repeat .. until and for .. loops:
   a. make top-level local definitions of repeat body visible in the condition;
   b. make the first expression after for... scope expression, extend the scope to the rest of the construct.