A Symbol Table Abstraction to Implement Languages with Explicit Scope Control

We are concerned with languages in which the programmer has explicit control over the referencing environment of a name. Several modern programming languages, including Ada, Euclid, Mesa, and Modula, implement these control capabilities. This paper describes a simple technique which uses the traditional concepts of a hashed symbol table and lexical level to solve many of the symbol table implemen-tation problems associated with explicit scope control. The primary ad-vantage of this technique is that a single symbol table abstraction can be used to simply and efficiently solve most problems in scope control.