SDD for Type Checking 

   Production Rule       Semantic Rule
   ================      ==================
   E -> E_1 + N          E_1.type == N.type  // semantic check 
   E -> N                E.type = N.type
   N -> float            N.type = F 
   N -> int              N.type = I

  Example. 5 + 3 + 2.   // passes semantic check 

  Annotated Syntax Tree and Parse Tree

             E.type==N.type? YES                      E
            /           |    \                      / | \
   E.type==N.type? YES  +     N.type=I            E   +  N
       /   |   \                |               / | \    |
 E.type=I  +  N.type=I         int            E   +  N   int 
     |         |                             /       |
  N.type=I    int                           N        int 
     |                                      |
    int                                    int