IF-THEN-ELSE considered harmful

Abstract

Although the if-then-else construct for flow of control is simple in some senses, and certainly superior to unrestricted GO TO logic, the indefinite replication of this structure leads to undesireable program constructs. Other, more extensible control structures may be added to programming languages, while regulating the unrestricted use of if-then-else, in such a way as to reduce the complexity of programs.