>I am aware of the TAG(), KEY(), IDXCOLLATE() and DESCENDING() functions for returning information about the makeup of an index Tagname and Expression. How can one find whether the Index in question has a FILTER expression or is created with the UNIQUE (not CANDIDATE) condition. I need to be able to determine these in order to check programatically whether a search expression will be RUSHMORE optimised or if an appropriate ORDER exists for a Column name.

Also, look at For(), Primary() and the SeeAlso attached to them in Help. I think there's a couple of other functions, like TagC(), TagNo() to look at.