question: static public Identifier toIdentifier ( Expression e ) { StringBuffer buf = new StringBuffer ( ) ; while ( e . op == FIELD ) { FieldExpression fe = ( FieldExpression ) e ; if ( fe . id == idThis || fe . id == idClass ) { return null ; } buf . insert ( 0 , fe . id ) ; buf . insert ( 0 , '.' ) ; e = fe . right ; } if ( e . op != IDENT ) { return null ; } buf . insert ( 0 , ( ( IdentifierExpression ) e ) . id ) ; return Identifier . lookup ( buf . toString ( ) ) ; }
target:  Convert an '.' expression to a qualified identifier