Document Type

Technical Report

Publication Date

Spring 3-1-1973


This paper presents semantic models of four parameter passing mechanisms utilized in various algebraic programming languages: Call by Value, Copy Restore, Call By Reference, and Call By Name. The correspondence between actual parameter values and formal parameter names is established by use of an environment directory and a denotation component. The environment directory associates each identifier in the program with a unique name, and the denotation component associates unique names with information concerning the value of the identifier denoted by the unique name. The various parameter passing mechanisms are first described informally. A tree structured model of each parameter passing mechanism is then presented. The paper concludes with a discussion of formalizing the models.