A finite state approach to operator classification
Wilf R. LaLonde · ACM SIGPLAN Notices · 1979
We consider the problem of uniquely classifying operators in expressions containing binary, prefix unary, and suffix unary operators e.g. binary + (addition), prefix unary ~ (negation), and suffix unary ! (factorial). Since the same name may be used to represent distinct operators in different classes, the problem is one of refinement. In the general case, it can be recast in a grammatical frameword whose solution requires all parse trees of an ambiguous grammar. We consider a much simpler finite state solution. More specifically, we consider an automaton based algorithm which refines the classifications of each operator to a unique class (when it exists) as a function of the allowed classifications of the neighboring operators. We do not consider the more complicated problem where operand types effect the result.