Activation :
The commencement of execution of a procedure. Each call to a procedure is referred to as an activation of that procedure. If the procedure in turn calls another procedure (or calls itself recursively), a new activation is said to have occurred. The earlier activation is then referred to as a pending activation.
Pending activations are often referred to as higher-level activations or higher-level procedures. When one procedure calls another (i.e., creates a new activation), the latter is often referred to as a lower-level activation or a lower-level procedure.
See Also : Activation Record, Activation Stack, Function, Procedure
Activation Record :
An internal data structure that contains information pertaining to an activation.
See Also : Activation, Activation Stack
Activation Stack :
An internal data structure that contains an activation record for the current activation and all pending activations.
See Also : Activation, Activation Record, Stack
Calling Program :
The procedure, or user-defined function that transferred control to the currently executing procedure or function. When the current procedure or user-defined function terminates with a RETURN statement, this is where control will return.
Function :
An executable block of code with an assigned name. Alternately, the collection of source code statements that define a function. Certain functions are supplied as part of Clipper; others are defined by the programmer using the FUNCTION or PROCEDURE declaration statements. The latter are referred to as user-defined functions.
The terms procedure and function are generally interchangeable. By convention, a function returns a value, while a procedure does not.
See Also: Activation, Parameter, Procedure
Identifier :
A name that identifies a function, procedure, variable, constant or other named entity in a source program. In Clipper language, identifiers must begin with an alphabetic character and may contain alphabetic characters, numeric characters, and the underscore character.
Information Hiding :
A fundamental programming principle that states that functions and programs should conceal their inner workings from other functions and programs. Stated simply: a function should possess only the knowledge necessary for it to accomplish its task. When one function calls another, the calling function should possess only the knowledge explicitly required to call the other function.
See Also: Encapsulation, Lexical Scoping, Modularity, Side Effect
Primitive :
A simple, low-level function used by other high-level functions or programs to perform a more complex task.
Procedure :
An executable block of code with an assigned name. Alternately, the collection of source code statements that define a procedure. In Clipper language, this can be a source file (.prg), a format file (.fmt), an explicitly declared procedure (PROCEDURE), or an explicitly declared function (FUNCTION).
The terms procedure and function are generally interchangeable. By convention, a function returns a value, while a procedure does not.
See Also: Activation, Function, Parameter
Return Value :
The value or reference returned by a function or method from a function call or message send.
Source Code :
The textual representation of a program or procedure.
See Also: Object File, Program File
User-defined Function :
See : Function
Word :
A series of characters in a match pattern or result pattern. Source text matches a word in a match pattern if the text is identical to the word or is an acceptable abbreviation of it. A word that appears in a result pattern is copied unmodified into the result text.
