This function already exist in the text extension
(String_LastIndexOf)

I agree that there should be more built-in functions for common operations like this, instead of having to use an extension.

IMHO:

1. Using an extension causes a slight detriment in code performance
2. Creates an overhead effort in eSpace configuration


The mapping of native code functions for Text(aka String) objects into a platform based function would speed up development and would also increase performance (although very slightly)  but it would provide a substantial increase in conceptual quality.

With version 6.0 you use the index function stating you want to search from end, trivially getting that effect.