DEFINE 
  AnL    [L],
  NotL   [A-KM-Z],
  IdChar [A-Za-z0-9_],
  Pid    IdChar IdChar+,
  Id     ([L] NotL IdChar*) |  (NotL IdChar+);

"~" {Pid} "~<:"          > 0 "\\INDEX{" 1 "}" ;
"~" {Pid} "~="           > 0 "\\INDEX{" 2 "}" ;
"PROCEDURE~" {Pid} "("   > 0 "\\INDEX{" 3 "}" ;
"PROCEDURE~" {Pid} "~("  > 0 "\\INDEX{" 4 "}" ;
"INTERFACE~" {Pid} ";"   > "INTERFACE " 5 ";\\beginindex{" 5 "}";
"END~" {Pid} "."         > "END " 6 ".\\endindex{" 6 "}"