ATNEXT(<C character>, <C string>, <N occurrence>)
 Evaluates position of the <n>th occurrence of character in a string.
 Returns <expN> position of <occurrence> of <character> in <string>.

 If LEN(<character>) is greater than 1, only the first character is
 looked at.

 ATNEXT( "A", "AAABBaCdda", 0) returns  0
 ATNEXT( "A", "AAABBaCdda", 1) returns  1
 ATNEXT( "A", "AAABBaCdda", 2) returns  2
 ATNEXT( "A", "AAABBaCdda", 3) returns  3
 ATNEXT( "A", "AAABBaCdda", 4) returns  0

 ATNEXT( "a", "AAABBaCdda", 1) returns  6
 ATNEXT( "a", "AAABBaCdda", 2) returns 10
 ATNEXT( "a", "AAABBaCdda", 3) returns  0


             Placed in the Public Domain by Tom Rettig Assoc.