David Gries
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Some ideas on data types in high-level languages
A number of issues are explored concerning the notion that a data type is a set of values together with a set of primitive operations on those values. Among these are the need for a notation for iterating over the elements of any finite set (instead of the more narrow for i := 1 to n notation), the use of the domain of an array as a data type, the need for a simple notation for allowing types of parameters to be themselves parameters (but in a restrictive fashion), and resulting problems with conversion of values from one type to another.
Verifying properties of parallel programs: an axiomatic approach
An axiomatic method for proving a number of properties of parallel programs is presented. Hoare has given a set of axioms for partial correctness, but they are not strong enough in most cases. This paper defines a more powerful deductive system which is in some sense complete for partial correctness. A crucial axiom provides for the use of auxiliary variables, which are added to a parallel program as an aid to proving it correct. The information in a partial correctness proof can be used to prove such properties as mutual exclusion, freedom from deadlock, and program termination. Techniques for verifying these properties are presented and illustrated by application to the dining philosophers problem.
A critical review of recent efforts to automate the writing of translators of programming languages is presented. The formal study of syntax and its application to translator writing are discussed in Section II. Various approaches to automating the postsyntactic (semantic) aspects of translator writing are discussed in Section III, and several related topics in Section IV.
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