Overview of Calling a Formula from a Formula

A formula can call another formula. This enables some modularity in formula organization. You specify the called formula name and any formula input or output names as TEXT values. The names are case-independent.

You can call a formula in any of these ways:

• Using a single call

• Using separate calls

As you write your formula, consider these points:

• Validation of the Called Formula

• Passing Contexts

• Call a Formula using any of these methods:

  • Using Separate Calls

  • Using a Single Self-Contained Call

• Use Cases to Compare Methods

Validation of the Called Formula

When a formula runs, it validates whether the called formula can be run, and whether the specified input and output data types are correct. You can use the IS_EXECUTABLE call to determine whether an executable formula with a specified name exists. You must compile the formula to make it available for the specified legislative data group. Also, the formula must be valid on the effective date on which the calling formula runs. In addition, the payroll code imposes extra restrictions based on formula type combinations.

Passing Contexts

Context values are inherited from the calling formula. You can also set or unset the context values explicitly in the nested formula call.

Alternative Methods to Call a Formula

You can call a formula fro within another formula in any of these ways:

• Using a series of separate calls

• Using a single self-contained call

Using Separate Calls

You can use three separate calls:

1. Set the Inputs

   Use the SET_INPUT call for each formula input and context that you need to explicitly set for the formula call. You don't need to specify all formula inputs and contexts. To explicitly unset a context value, use the SET_INPUT call without passing the optional value parameter. Any extra inputs specified in SET_INPUT calls are ignored.

2. Call the Formula

   Use the EXECUTE call to call a formula.

3. Get the Formula Outputs

   Use one or more GET_OUTPUT calls to fetch outputs from the last formula call.

When the formula runs, it returns an execution error in these scenarios:

• The called formula isn't executable.

• The called formula is already running.

• The data type of an input variable (specified using SET_INPUT) or an output variable (specified using GET_OUTPUT) doesn't match its actual data type within the called formula.

This table summarizes the methods for calling a formula using separate calls.

Method	Use To
SET_INPUT(input [,value])	Sets the value of an input or a context to the value specified in the value parameter. The value parameter is optional. If you specify the value parameter, the input is set to this value. If you don't specify the value parameter, the input or context is passed as unset to the formula. The data type of the value is the expected data type for the input. If you use a context in a SET_INPUT call, its value will be set to the value in the calling formula.
EXECUTE(formula)	Executes the called formula.
GET_OUTPUT(output, default-value)	Gets the value of the output parameter after calling a formula. If there is no formula output called 'output' or it's not set, the formula returns the value specified in the default value parameter. The data type of default value is the expected data type for the output.

Note: Formula inputs that are set using SET_INPUT persist as long as no EXECUTE or GET_OUTPUT calls are made. Output values from a called formula persist as long as no SET_INPUT or new EXECUTE calls are made. When the calling formula exits, the process removes any saved input or output values.

Using a Single Self-Contained Call

Here's what a single self-contained call does:

• Clears the input values at the start to not use prior SET_INPUT call values.

• Discards the outputs at the end so that the subsequent GET_OUTPUT calls only return the default values.

Here's how you can use the CALL_FORMULA method:

CALL_FORMULA(formula, [set statement, get statement])

A SET statement is a SET_INPUT call. A GET statement assigns the result of a GET_OUTPUT call to a variable in the calling formula. The calls execute in this order:

1. SET_INPUT calls

2. EXECUTE call

3. GET_OUTPUT assignments

The compiler generates code to execute in this order, even if SET and GET statements are interspersed.