Creating Temporary Fields Independent of a Master File

Syntax: How to Define a Function

DEFINE FUNCTION name (argument1/format1,..., argumentn/formatn)
[tempvariablea/formata [TITLE 'line1[,line2 ...']
 [DESCRiption 'description'] = expressiona;] 
   .
   .
   .
[tempvariablex/formatx = expressionx;]  
name/format = [result_expression];
END

where:

name

Is the name of the function, up to 64 characters. This must be the last field calculated in the function, and is used to return the value of the function to the calling procedure.

argument1...argumentn

Are the argument names. They can be any names that comply with WebFOCUS field naming rules.

format1...formatn

Are the formats of the function arguments.

If the format of an argument is alphanumeric, the argument value must also be alphanumeric. Shorter arguments are padded on the right with blanks, and longer arguments are truncated.

If the format of an argument is numeric, the argument value must also be numeric. To prevent unexpected results, you must be consistent in your use of data types.

tempvariablea...tempvariablex

Are temporary fields. Temporary fields hold intermediate values used in the function. You can define as many temporary fields as you need.

tempformata...tempformatx

Are the formats of the temporary fields.

line1,line2 ...

Are the lines of default column title to be displayed for the virtual field unless overridden by an AS phrase.

description

Is the description to be associated with the virtual field, enclosed in single quotation marks. The description displays in the tools that browse Master Files.

expressiona...expressionx

Are the expressions that calculate the temporary field values. The expressions can use parameters, constants, and other temporary fields defined in the same function.

format

Is the format of the value the function returns.

result_expression

Is the expression that calculates the value returned by the function. The expression can use parameters, constants, and temporary fields defined in the same function.

All names defined in the body of the function are local to the function. The last field defined before the END command in the function definition must have the same name as the function, and represents the return value for the function.

Reference: DEFINE Function Limits and Restrictions

The number of functions you can define and use in a session is virtually unlimited.
A DEFINE function is cleared with the DEFINE FUNCTION CLEAR command. It is not cleared by issuing a join, or by any WebFOCUS command.
When an expression tries to use a cleared function, an error appears.
DEFINE functions can call other DEFINE functions, but cannot call themselves.
If you overwrite or clear a DEFINE function, a subsequent attempt to use a temporary field that refers to the function generates the following warning:
```
(FOC03665) Error loading external function '%1'
```

Example: Defining a Function

The following example creates and calls the SUBTRACT function. SUBTRACT performs a calculation with the arguments VAL1 and VAL2.

DEFINE FUNCTION SUBTRACT (VAL1/D8, VAL2/D8) 
 SUBTRACT/D8.2 = VAL1 - VAL2; 
END

TABLE FILE MOVIES 
 PRINT TITLE LISTPR IN 35 WHOLESALEPR AND
 COMPUTE PROFIT/D8.2 = SUBTRACT(LISTPR,WHOLESALEPR);
 BY CATEGORY
   WHERE CATEGORY EQ 'MYSTERY' OR 'ACTION'
END

The output is:

CATEGORY	TITLE	LISTPR	WHOLESALEPR	PROFIT
ACTION	JAWS	19.95	10.99	8.96
	ROBOCOP	19.98	11.50	8.48
	TOTAL RECALL	19.99	11.99	8.00
	TOP GUN	14.95	9.99	4.96
	RAMBO III	19.95	10.99	8.96
MYSTERY	REAR WINDOW	19.98	9.00	10.98
	VERTIGO	19.98	9.00	10.98
	FATAL ATTRACTION	29.98	15.99	13.99
	NORTH BY NORTHWEST	19.98	9.00	10.98
	DEAD RINGERS	25.99	15.99	10.00
	MORNING AFTER, THE	19.95	9.99	9.96
	PSYCHO	19.98	9.00	10.98
	BIRDS, THE	19.98	9.00	10.98
	SEA OF LOVE	59.99	30.00	29.99

Procedure: How to Display DEFINE Functions

Issue the following command from the Command Console:

? FUNCTION

Example: Displaying DEFINE Functions

Issuing the command

? FUNCTION

displays information similar to the following:

FUNCTIONS	CURRENTLY	ACTIVE

NAME	FORMAT	PARAMETER	FORMAT
----------	---------	---------	-------
SUBTRACT	D8.2	VAL1	D8
		VAL2	D8

If you issue the ? FUNCTION command when no functions are defined, the following appears: