Compaq AA-PWCBD-TE manual DEC Text Processing Utility Data Types Array Data Type

DEC Text Processing Utility Data Types

3.1 Array Data Type

3.1 Array Data Type

An array is a structure for storing and manipulating a group of elements. These elements can be of any data type. You create arrays with the CREATE_ARRAY built-in procedure. For example, the following statement creates the array new_array:

new_array := CREATE_ARRAY;

You can delete arrays with the DELETE built-in procedure.

When you create an array, you can optionally direct DECTPU to allocate a specified number of integer-indexed array elements. DECTPU processes this block of preallocated elements quickly. You can direct DECTPU to create such a block of elements only at the time you create the array.

The following statement creates the array int_array, directs DECTPU to allocate 10 sequential, integer-indexed elements to the array, and specifies that the lowest index value should be 1:

int_array := CREATE_ARRAY (10, 1);

Regardless of whether you specify a preallocated block of elements, you can always add array elements dynamically. Dynamically added elements can be of any data type except learn, pattern, program, or unspecified. You can mix the data types of indexes in an array.

In the following code fragment, the array mix_array is created and the integer 1 is stored in the array element indexed by the marker mark1.

mix_array := CREATE_ARRAY; mark1 := MARK (NONE); mix_array {mark1} := 1; mix_array {"Kansas"} := "Toto";

You can index dynamic elements with integers, even if this means that the array ends up with more integer-indexed elements than you specified when you created the array. DECTPU does not process dynamically added integer-indexed elements as quickly as it processes preallocated elements.

To refer to an array element, use the name of an existing array variable followed by the array index enclosed in braces ( { } ) or parentheses ( ( ) ). For example, if you create an array and store it in the variable my_array, the following are valid element names:

my_array{2}

my_array("fred")

To create an element dynamically for an existing array, use the new element as the target of an assignment statement. The following statement creates the element "string1" in the array my_array and assigns the element to the string "Topeka":

my_array{"string1"} := "Topeka";

In the following example, the first statement creates an integer-indexed array, int_array. The array has 10 elements; the first element starts at index 1. The second statement stores a string in the first integer-indexed element of the array. The third statement stores a buffer in the eighth element of the array. The fourth statement adds an integer-indexed element dynamically. This new element contains a string.

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