IMan (VB)Script Language Reference

IMan uses our own variant of the Scripting language. The (VB) Scripting language is used throughout IMan: Map, Filter, Aggregate transforms; Script Task; evaluated expressions such as File Names and URLs.

The main characteristics of the IMan (VB) Script Language:

  • Based on VBScript
    • It is dynamically typed - There are no explicit type (String, Integer, Boolean) declarations.
    • Most of the constructs and features of VBScript are valid an usable in IMan.
    • All the inbuilt VBScript Functions such as (Mid, Replace, Instr) can be invoked. These are augmented by numerous IMan specific functions such as Lookup, Sum, Count.
  • Field values from IMan can be referered with %FieldName syntax.

  • Expressions do not have function opening or function close statements.

  • There is no explicit expression result declaration - last line of the expression is the result.

Components of the (VB)Script Language

The IMan (VB) Script language is a full-featured language consisting of features in a language: variables, control flow and looping.

  • Field and Record Evaluation Expressions

    • (On this page) What are expressions.
  • Field References
    • (On this page) How to reference IMan data from in an expression.
  • Syntax
    • General Script syntax such as reserved names and comments.
  • Functions
    • How to call (and define your own) functions such as Mid, Lookup, etc.
  • Variables
    • How to declare variables to hold temporary values in expressions or functions.
  • Operators
    • How to use the different operators such as +, /, Mod, And, Or, &.
  • Decisions
    • How to use If...Then...Else type statements.
  • Loops
    • How to perform loops on collections or arrays of data.
    • Looping should not be confused with the general Data Processing Pattern.
  • Arrays
    • How to declare and resize Arrays / collections of data.
  • Error Handling
    • A short discussion on error handling.

What is a Expression?

An expression is a script statement. It returns a value.

This may be a small, single line script, or a multi-line script.

Field and Record Evaluation Expressions

Expressions can be found in many places in IMan and classified into three broad categories.

  • Field expression
    • Individual field level and are used to set field values - found in Map and Aggregate transforms.
    • Can be written over multiple lines and support local variables.
  • Record evaluation expression
    • Record evaluation expressions apply to an entire record, with all its field and are used for conditional evaluation such as the Filter and Aggregate transforms.
    • Can be written over multiple lines and support local variables.

  • Inline Expressions

    • In-line expressions are limited to a single line which must evaluate to a result. These expressions are used primarily in transform set-up fields to dynamically generate a specific entry, such as a file name in a Writer transform.
    • Are a single line i.e. are purely functional - they do not support any variables.
The last line of the formula is used as the result.

Example 1

Multi-line Function with a Valid Return Value

Dim NetValue
NetValue = %GrossValue - %TaxTotal
NetValue * -1 'The last line is the result

Example 2

Multi-line Function with an Invalid Return Value - the last line is variable declaration.

Dim NetValue
NetValue = %GrossValue - %TaxTotal
NetValue * -1
Dim CalculatedValue 'Invalid - The last line is a variable declaration.

Example 3

The return value is supposed to be NetValue, but the formula actually returns a Boolean comparison of the NetValue variable and the difference of the GrossValue and TaxTotal fields.

Dim NetValue
NetValue = %GrossValue - %TaxTotal

The correct formula should be:

Dim NetValue
NetValue = %GrossValue - %TaxTotal
NetValue * -1

Which could be further simplified to a single one line expression:

(%GrossValue - %TaxTotal) * -1

Field References

Field references allow data in the IMan dataset to be referenced and manipulated.

Field references have the following syntax:

%[Field Name]

or

%FieldName

Where:

  • %
    • Identifies the following statement as a field reference.
  • FieldName
    • The name of the field being referenced.

If there are spaces or special characters within the field name/transaction Id, enclose the field references in square brackets.

Example 1

The following example uses two field references GrossTotal and TaxTotal - each of these refer to fields in the dataset. 

Dim NetValue
NetValue = %GrossValue - %TaxTotal
NetValue * -1 'The last line is the result

If the GrossTotal and TaxTotal fields had 1200 and 400 respectively the resulting expression would be -800.

The same example can be shown with the square bracket around the field reference syntax.

Example 2

Dim NetValue
NetValue = %[GrossValue] - %[TaxTotal]
NetValue * -1 'The last line is the result