25. Glossary

In this chapter, we shortly describe the main terms used in this book with references to the relevant sections in the book.

The rightmost column is supposed to contain a link to the part(s) of the book where the term is introduced. It is currently incomplete.

Term Explanation References
Access modifiers Supplementary properties that restrict access to attributes of an object including %public, %private, %protected, %package_boundary and %package. mkRef("Visibility mechanisms")
Action The accomplishment of creating/destroying physical phenomena and/or changing properties of physical phenomena in a domain.
Atomic operation An operation that cannot be interrupted while it is being executed. 
Active object An object that performs computations of its own: a program object, a coroutine or parallel object. An object that includes statements that are executed as part of the generation of the object, is not considered an active object.
Activity A partial ordered sequence of actions.
Attribute A local data-item, method, or class of an object.
Attribute accessor An expression that describes access to an attribute of a specific object. mkRef("The first program")
Actual parameter If the formal parameter is a data-item, then an actual parameter is the value of an expression assigned to the formal parameter at the invocation of a method or instantiation of a class.
If the formal parameter is a virtual method or virtual class, then an actual parameter is a binding of the virtual.
Argument Alternative term for actual parameter.
Class A template for objects with identical structure. mkRef("Classes")
Class instantiation The computation of generating an object from a class, and executing its statements.
Similar to method invocation.
Control structure abstraction,
control abstraction
Alternative term for a control method.
Control flow The order in which the operations of a program are performed. It determines how a program moves from one operation to another based on the state of the objects.
Control structure A statement that specifies the order of execution of other statements based on state of the objects and thus controls the control flow of a program.
Control structure method,
Control method
A method that defines a control structure.
Computation A partial ordering of operations executed by a computer.
Coroutine Shorthand for coroutine object
Coroutine object An active object that represents an activity that may be suspended and later resumed at the point of suspension.
Data-item A constant or variable object reference or value object.
Datum A piece of information that may be a value or an object reference.
Declaration A description of a constant or variable data-item, a class or a method in an object descriptor or method descriptor.
Derived An object descriptor and class is said to be derived from its superclass.
Direct superclass The direct superclass is the class from which the class/singular object is explicitly derived as specified in the object descriptor for the class/singular object
Expression A description/syntactic element that describes a computation of a value.
Formal parameter A formal parameter of a method or class may be a variable data-item or a virtual method or virtual class.
Se also actual parameter.
Function A method that computes a value solely based on the values of its parameters. It does not read or modify data-items in its enclosing object or other objects.
Ghost object An object that is used solely for the purpose of explaining a given programming language mechanism.
Identity A physical phenomena has an identity. Physical phenomena are distinct which means that they have different identities. mkRef("On representing phenomena")
Inheritance An alternative term for the subclass mechanism.
Item A declaration or a statement in an object-descriptor.
Intrinsic object An object that is a declared using obj, is generated as part of the generation of the object containing the declaration and exists during the lifetime of this object.
Invoker The object (class object or method object) executing the method invocation that generates a given method object – the invokee. mkRef("Method details")
Invokee The method object being generated as part of a method invocation executed by an object or method object – the invoker. mkRef("Method details")
Mainpart The items defined in an object-descriptor excluding the direct superclass.
Method A template for computations with identical structure.
Method generation The computation of generating a method object; includes generation of possible data-items and assignments of possible parameters.
Similar to object generation.
Method invocation The computation of a method generation from a method description, followed by execution of its statements.
Similar to object instantiation
Material object A singular object declared using obj or an instance of a class.
Method object An object created from a method.
Module An object descriptor for a singular object that is organized in the qBetaWorld hierarchy and mapped to a folder and file in the filesystem.
Object Objects are the basic, physical entities that exist in computers; objects are the building blocks of computational processes.
An object has variable and/or constant datums, intrinsic objects, classes, methods, and a computation part.
A material objects has in addition an identity.
A method objects does not have an identity.
mkRef("Objects")
Object-descriptor A description of the structure of an object consisting of a possible superclass, and possible items.
Object generation The computation of generating an object; includes generation of possible data-items and assignments of possible parameters.
Similar to method generation.
Object instantiation The computation of an object generation from a object descriptor, followed by execution of its statements.
Similar to method invocation.
Object reference A data-item that may hold a reference to an object. See also Reference.
Operation An action executed by a computer. mkRef("More on computers executing programs")
Parallel object An active object that executes actions in parallel with other parallel objects.
Parameter Shorthand for formal parameter. See also actual parameter and argument.
Program A module that is intended for execution.
Reference Short-hand for object-reference.
Scope The part of the qBetaWorld where a given name is visible.
Singular object An object that is one of its kind and not an instance of a class.
Singular method object A method object that is one of its kind and not an instance of a method.
Statement A description of an activity (action?) in an object-descriptor.
Structure Shorthand for object structure.
Subclass A class that is derived from another class – its direct superclass, and inherits attributes and statements from the superclass.
Superclass A class from which other classes are derived. See also direct superclass. mkRef("Common superclass")
Submethod A method that is derived from another method – its direct supermethod, and inherits attributes and statements from the supermethod.
Supermethod A method from which other methods are derived.
Type A concept that covers a class of values. This is a simplified defintion of a type intended for programming – the mathematical concept of a type is much more complicated and exists in different variants.
Value A mathematical entity like a number, point, polygon, etc.
Value object An object that is an instance of a subclass of class Value; the object is embedded in a holding object and intended for representing a value.
Value type A class that is a subclass of class Value. See also Type.