We present a denotational semantics for an Algol-like language Alg, which is fully abstract for the second order subset of Alg. This constitutes the rst signiicant full abstraction result for a block structured language with local variables. As all the published`test equivalences' 13, 8, 23] for Algol-like languages are contained in the second order subset, they can all be validated (easily) in...

Many object-oriented languages used in practice descend from Algol. With this motivation, we study the theoretical issues underlying such languages via the theory of Algollike languages. It is shown that the basic framework of this theory extends cleanly and elegantly to the concepts of objects and classes. An important idea that comes to light is that classes are abstract data types, whose the...

In section 3, an algorithm performing so called generalized good translation of formal languages is given in the form of an ALGOL 60 procedure. Its description is given in section 2. It is possible to translate from a formal (context-free) language into other one with help of this algorithm if certain conditions hold for both grammars. At the same time, some parts of output text may correspond ...

The undghtforward way of elaborating an assignation d :its in an ALGOL 68 implementation is (1): • elaborate the destination d and the source s, yielding a name N and a value V; • assign fire value V to the Elaine N. In many cases, the elaboration of s will consist of the ovation of a copy on the working stack of an already existing value V. This value is assigned to N by copying it once more i...

The paper provides an informal account of CPL, a new programming language currently being implemented for the Titan at Cambridge and the Atlas at London University. CPL is based on, and contains the concepts of, ALGOL 60. In addition there are extended data descriptions, command and expression structures, provision for manipulating non-numerical objects, and comprehensive input-output facilitie...