Operation expressions in MARY

Conventional languages are serial from statement to statement unless broken by explicit parenthesization such as BEGIN blocks or their equivalent in other languages. However, they are not serial within statements, but possess a complex priority scheme which seems to have little justification except historical notation in a few branches of mathematics. By making the elaboration sequence consistant in all contexts, MARY has succeeded in introducing several powerful new constructions in an orthagonal manner, while retaining clarity and ease of notation. This paper discusses one construction, the operation expression, in which program portions are evaluated to yield an operation to be applied to constant operands, instead of yielding an operand to be manipulated by constant operators.