Included with IDEA are over 100 @Functions used by the Equation Editor. For the majority of users, this list is enough. However, there are circumstances that arise where a function that is required does not exist. IDEA lets you create your own custom functions.
In the Equation Editor, custom functions are preceded by the pound sign (#). For instance, you might create a custom function called #ValidateABN.
Also custom functions have the file name extension *.ideafunc.
The #ValidateABN custom function verifies an Australian Business Number (ABN).
![](https://static.zohocdn.com/zoho-desk-editor/static/images/caution.png)
Warning: Please be advised that this custom function is provided for demonstration purposes only. It is provided without a warranty of any kind.
Return Type: Numeric, if the ABN is valid, 1 (True) is returned. If the ABN is invalid, 0 (False) is returned.
You can download the custom function from the CaseWare Passport.
Custom functions are located on the IDEAScript and Python Tab > IDEAScript Custom Functions
1. Scroll down and click on the Validate ABN(Australian Business Number) custom function to download save in your Local Library folder C:\Users\[User Name]\Documents\My IDEA Documents\Local Library\Custom Functions.ILB
2. Unzip the downloaded file, ValidateABN.zip in the Custom Functions folder. Once a custom function has been added to the Custom Functions Library group, it is added to the functions list in the Equation Editor.
3. The ValidateABN function now appears in the Equation Editor under the Customs Functions>uncategorized group