It would be very helpful to have a "Find" function for strings that search for the presence of one or more characters starting with the last character in the string and moving from right to left (i.e. a "Reverse Find"). The particular use case I was trying to address was to search for "" so as to find the last subdirectory in a part in order to get the path of its parent directory using the "Left" function to grab the leftmost characters of my original path up to but not after the leftmost occurrence of "/" in the string.
For example @Left('C:acd',@StringLength('C:acd')-@ReverseFindString('C:acd','',-1,caseSensitive=TRUE) = 'C:ac'