FileMaker Pro Custom Functions

Let ([ vlist = "¶" & valueList & "¶"; vtext = "¶" & valueString & "¶"; pos = If ( occurrence = 0; 0; Position( vlist; vtext; If ( occurrence < 0; Length ( vlist ); 1 ); If ( occurrence < 0; -1; 1 ) ) ); index = If ( pos; ValueCount ( Left ( vlist; pos ) ); 0 ); match = Exact ( GetValue ( valueList; index ); valueString ); occurrence = Case ( pos = 0; 0; matchCase; If ( match; occurrence + If ( occurrence > 0; -1; 1 ); occurrence); occurrence + If ( occurrence > 0; -1; 1 ) ); vlist = Case ( occurrence < 0; Left ( valueList; pos - 1 ); occurrence > 0; Right ( valueList; Length ( valueList ) - ( pos + Length ( valueString ) )); "" ); idx2 = If ( occurrence ≠ 0; GetValueIndex ( vlist ; valueString ; matchCase ; occurrence ); 0 ); index = Case ( occurrence < 0; idx2; occurrence > 0; If ( idx2 = 0; 0; index + idx2); index )]; index ) /* GetValueIndex (valueList, valueString, matchCase, occurrence) by Lewis C. Lorenz. 9-20-2011: Created 9-22-2011: Updated. Retrieve the index of the matching valueString in the valueList. Returns 0 if not found. Optionally toggle case-sensitive searching by passing a boolean through matchCase. Optionally search for specific valueString occurrence (a negative occurrence number causes backward search from the end of the valueList). Examples: ValueListIndex ("Alpha¶Bravo¶Charlie¶Echo", "charlie", False, 1) = 3 ValueListIndex ("Alpha¶Bravo¶Charlie¶Echo", "charlie", True, 1) = 0 ValueListIndex ("James¶Bill¶James¶Frank¶James¶Ed", "james", False, -2) = 3 */
 Then copy & paste into FileMaker Advanced's Edit Custom Function window.