pTAL Reference Manual (H06.08+)

Language Elements

HP pTAL Reference Manual—523746-006

2-10

Variables

A variable is a symbolic representation of data. It can be a single-element variable or a

multiple-element variable. You use variables to store data that can change during

program execution.

Before you can access data stored in a variable you must either:

•

Initialize the variable with a value when you declare the variable

•

Assign a value to the variable after you declare the variable

Scope

Every declared item in a pTAL program has a scope that determines where in the

program it is visible (after the point of declaration).

Formal parameters of procedures and subprocedures have local and sublocal scope,

respectively.

Table 2-9. Variable Types

Variable Type Description

Simple variable A variable that contains one element of a specified data type

Array A variable that contains multiple elements of the same data type

Structure A variable that can contain variables of different data types

Substructure A structure nested within a structure or substructure

Structure item A simple variable, array, simple pointer, substructure, or

structure pointer declared in a structure or substructure; also

known as a structure field

Nonstructure pointer A variable that contains a memory address, usually of a simple

variable or an array element, which you can access with this

nonstructure pointer

Structure pointer A variable that contains the memory address of a structure,

which you can access with this structure pointer

Scope Declared in a ... Visible ...

Global Program Everywhere in the program

Local Procedure Only in the procedure that declares it (including the

subprocedures of that procedure)

Sublocal Subprocedure Only in the subprocedure that declares it