FIND_MEMBER

 The FIND_MEMBER function locates the first character in a string
 that is a member of a specified set and returns an integer value
 indicating the position of the  character  in  the  string;  the
 function  returns  0  if  the  characters in the string were not
 members of the set.


 Syntax:

    FIND_MEMBER( string, char-set )


 The 'string' parameter is a string value, and the 'char-set'  is
 a value of type SET OF CHAR.