Data Transformation Engine Functions and Expressions Reference Guide

Chapter 1 - Expressions and Evaluations Using Functions in Expressions

Functions and Expressions Reference Guide

Nested Input Arguments

When a function, operator, or map is used as an input argument, each of these

has arguments of its own. Arguments of other arguments are said to be nested.

For example, in the use of the

ABS function, you can use a function as an

argument:

ABS ( UNIQUE ( Quantity:LineItem ) )

The output of the UNIQUE function becomes the input argument to the ABS

function.

Output Arguments

The output argument of a function indicates the type of object the function

produces and the number of objects a function can produce. An output argument

is specified as one of the following:

♦ A single data object of a type

♦ A series of data objects of the same type

♦ TRUE or FALSE

Note If the output of a function is a series, that function may be used only in a map rule

in the Map Designer. It cannot be used in a component rule in the Type Designer.

For example, you cannot use the CLONE, EXTRACT, REJECT, SORTDOWN, SORTUP

or UNIQUE functions in the Type Designer.

Function Arguments and Evaluation

When a function is evaluated, the number of argument objects used for one

evaluation depends on the function. In the specification of the syntax for a

function, the number of input objects that can be used for each argument for one

function evaluation is expressed as "single" or "series".

Some functions use a single object as the value of an argument for one

evaluation. For example, the

ABS function uses a single object as the value of its

argument for one evaluation.

ABS ( Quantity:LineItem )

When a single object is used for one evaluation, the function itself can evaluate

many times if there is more than one data object that fits the argument definition.

For example, if there were ten Quantity:LineItem data objects, the

ABS function

could evaluate ten times.