function(option)
v Another function
function(function(arguments))
v Combination of argument types
function('With a literal string', 55, option)
When the function returns a value, and all functions must return values, the value
replaces the function call. In the following example, the value returned is added to 7
and the sum is displayed.
SAY 7 + function(arguments)
A function call generally appears in an expression. Therefore a function call, like an
expression, does not usually appear in an instruction by itself.
Example of a Function
Calculations represented by functions often require many instructions. For instance,
the simple calculation for finding the highest number in a group of three numbers,
might be written as follows:
Finding a Maximum Number
/***************************** REXX ********************************/
/* This exec receives three numbers from a user and analyzes which */
/* number is the greatest. */
/*******************************************************************/
PARSE ARG number1, number2, number3 .
IF number1 > number2 THEN
IF number1 > number3 THEN
greatest = number1
ELSE
greatest = number3
ELSE
IF number2 > number3 THEN
greatest = number2
ELSE
greatest = number3
RETURN greatest
Rather than writing multiple instructions every time you want to find the maximum of
a group of three numbers, you can use a built-in function that does the calculation
for you and returns the maximum number. The function is called MAX and is used
as follows:
MAX(number1,number2,number3,...)
To find the maximum of 45, -2, number, 199, and put the maximum into the symbol
biggest, write the following instruction:
biggest = MAX(45,-2,number,199)
What is a Function?
62
z/OS V1R1.0 TSO/E REXX User’s Guide
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