Class Of Programming Languages Research Articles

Deterministic and nondeterministic flowchart interpretations

Programming languages are studied in the abstract. Algebraic theories supply the syntax for programming languages. Semantics is provided by coproduct preserving functors from the algebraic theory to some semantic category with finite coproducts. Deterministic programming languages are provided when the semantic domain is the category of pointed sets and point preserving functions. Nondeterministic programming languages occur when the semantic domain is the category of Abelian monoids. The class of all nondeterministic programming languages with a fixed syntax is shown to be a variety of algebras. All classes of deterministic programming languages that allow branching are shown to be nonvarietal. Other properties of classes of programming languages are studied using category theory.

Static determination of dynamic properties of generalized type unions

The classical programming languages such as PASCAL or ALGOL 68 do not provide full data type security. Run-time errors are not precluded on basic operations. Type safety necessitates a refinement of the data type notion which allows subtypes. The compiler must also be able to ensure that basic operations are applicable. This verification consists in determining a local subtype of globally declared variables or constants. This may be achieved by improved compiler capabilities to analyze the program properties or by language constructs which permit the expression of these properties. Both approaches are discussed and illustrated by the problems of access to records via pointers, access to variants of record structures, determination of disjoint collections of linked records, and determination of integer subrange. Both approaches are complementary and a balance must be found between what must be specified by the programmer and what must be discovered by the compiler.

Static determination of dynamic properties of generalized type unions

The classical programming languages such as PASCAL or ALGOL 68 do not provide full data type security. Run-time errors are not precluded on basic operations. Type safety necessitates a refinement of the data type notion which allows subtypes. The compiler must also be able to ensure that basic operations are applicable. This verification consists in determining a local subtype of globally declared variables or constants. This may be achieved by improved compiler capabilities to analyze the program properties or by language constructs which permit the expression of these properties. Both approaches are discussed and illustrated by the problems of access to records via pointers, access to variants of record structures, determination of disjoint collections of linked records, and determination of integer subrange. Both approaches are complementary and a balance must be found between what must be specified by the programmer and what must be discovered by the compiler.

Static determination of dynamic properties of generalized type unions

The classical programming languages such as PASCAL or ALGOL 68 do not provide full data type security. Run-time errors are not precluded on basic operations. Type safety necessitates a refinement of the data type notion which allows subtypes. The compiler must also be able to ensure that basic operations are applicable. This verification consists in determining a local subtype of globally declared variables or constants. This may be achieved by improved compiler capabilities to analyze the program properties or by language constructs which permit the expression of these properties. Both approaches are discussed and illustrated by the problems of access to records via pointers, access to variants of record structures, determination of disjoint collections of linked records, and determination of integer subrange. Both approaches are complementary and a balance must be found between what must be specified by the programmer and what must be discovered by the compiler.

An overview of nonprocedural languages

This paper attempts to describe some of the basic characteristics and issues involving the class of programming languages commonly referred to as “nonprocedural” or “very high level”. The paper discusses major issues such as terminology, relativeness, and arbitrary sequencing. Five features of nonprocedural languages are described, and a number of specific languages are discussed briefly. A short history of the subject is included.

GLOSS

A program of a high level language can be executed either by applying a suitable high level machine to the program or by translating the program to an equivalent program in another language for which a machine exists. Constructing a high level machine for each language is an interesting solution, but such a solution requires the construction of many machines and also does not enable the semanticist to compare programming languages. Using an existing conventional machine whose machine language is the target language of a translator provides an un-interesting solution which also does not allow the semanticist to easily compare programming languages. If we use a high level machine, such as GLOSS, whose machine language is the target language of a translator, then we can write a translator which merely rearranges syntax and does not lose any semantics. Such a solution is interesting to the semanticist if a large class of programming languages can be translated into this high level machine by syntax rearrangement because the high level machine can serve as a medium of programming language comparison.