Block structures, indirect addressing, and garbage collection

Abstract

Programming languages have included explicit or implicit block structures to provide a naming convenience for the programmer. However, when indirect addressing is used, as in SNOBOL, naming constraints may be introduced. Two modifications to SNOBOL are described, resulting in two desirable consequences: (1) naming constraints disappear even when there is indirect addressing within function definitions; and (2) there is a significant saving in the number of calls to the garbage collector, because some garbage is collected, at little expense, each time a function returns to its calling program. These modifications have been implemented as an extension to a SNOBOL dialect. © 1969, ACM. All rights reserved.