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Parameterizing user-defined functions

You can use an in-out parameter that is configured as an expression variable to fully or partially parameterize a user-defined function in an expression.

To parameterize a user-defined function, create a string in-out parameter and enable

Is expression variable

. To fully parameterize the user-defined function, use the parameter in place of the entire user-defined function. To partially parameterize the user-defined function, use the in-out parameter in place of the user-defined function arguments. At run time, resolve the parameter in the mapping task or parameter file.

For more information about in-out parameters, see

Mappings

Full parameterization

Use full parameterization when you want to parameterize the user-defined function in an expression. When you use an in-out parameter in place of a user-defined function, parameter names are case sensitive. When you resolve the parameter, include the :UDF prefix.

For example, you have the in-out parameter $$UDFparameter and you use it to fully parameterize a user-defined function. In the parameter file, you resolve the parameter with the following function:

$$UDFparameter=:UDF.RemoveSpaces(names)

Partial parameterization

Use partial parameterization when you want to parameterize the field name in the argument, or when you want to parameterize a nested user-defined function. When you parameterize a nested user-defined function, the parameter in the function argument must be in capital letters. You can nest one user-defined function.

For example, you create the in-out parameter $$UDF and configure it as an expression variable. In the expression, you configure the following function:

:UDF.RemoveSpaces($$UDF)

In the parameter file, you resolve the parameter with the following function:

$$UDF=:UDF.Replace_Chars_special(Name)

Full and partial parameterization

You can use both full and partial parameterization within the same function. Use both full and partial parameterization when you want to parameterize the user-defined function and the function arguments.

For example, you have the in-out parameter $$UDF and use it in an expression to fully parameterize a user-defined function. In the parameter file, you resolve the parameter with the following values:

$$UDF=:UDF.Replace_Chars_special($$Field)
$$Field=Name

When you want to pass either the CurrentTaskName, CurrentRunId, or SESSSTARTTIME system variable as an argument in a fully parameterized user-defined function, you must pass the system variable through another in-out parameter.

For example, you want use CurrentTaskName in a parameterized user-defined function. You use the in-out parameter $$UDF to fully parameterize the function. In the parameter file, you resolve the parameter with the following values:

$$UDF=:UDF.udf_InitcapLtrim($$tasknameparam)
$$tasknameparam='$CurrentTaskName'

Creating expressions with user-defined functions

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Table of Contents

Components

Components

Parameterizing user-defined functions

Parameterizing user-defined functions

Full parameterization

Partial parameterization

Full and partial parameterization