Type Systems and Data Types in Programming Languages

Scheme

Languages that have no explicit types or translation-time typing.

Data type

A set of values.

Type checking

The process a translator goes through to determine whether the type information in a program is consistent.

Type constructors

Used to construct complex types from basic types.

Enumerated types

Sets whose elements are named and listed explicitly.

Subtype mechanism

Used to create a new data type that contains a subset of a known data type.

Recursive type

A type that uses itself in its declaration.

Reference types

Types constructed using type constructors in Java.

Structural equivalence

When two objects are built in the same way using the same type constructors from the same simple types.

Dynamic checking

If information is maintained and checked at runtime.

Assignment compatibility

A term used for the type correctness of assignments.

Implicit conversions

Often referred to as coercions.

Type descriptor

The primary data structure used to represent type attributes.

Short-circuit evaluation

Evaluation that stops once the truth value of a Boolean expression is known.

Guards

the Boolean expressions in the guarded if statement

Dangling-else problem

An ambiguity in which it cannot be determined which if statement should be associated with a single else statement.

Union

Like a structure, except all members occupy the same memory area.

Pointer to a structure

Can be used as a function parameter, structure member, or function return type.

Structure pointer

Contains the address of a structure variable.

Dereference a structure pointer

The appropriate operator is the structure pointer operator, ->.