Exercise 1.

We consider the following translation scheme.

S	$\longmapsto$	A {C.i := A.s} C
S	$\longmapsto$	AB {C.i := A.s} C
A	$\longmapsto$	int {A.s := int.val}
B	$\longmapsto$	id {}
C	$\longmapsto$	int {C.s := C.i + int.val}

where S, A, B, C are non-terminals, int and id are terminals, C.i is an inherited attribute, A.s and int.val are synthesized attributes. Write a YACC program for this translation scheme.

Answer 1  

S     : A C 
      | A B M C
      ;
A     : TOK_INT {$$ = $1; }
      ;
B     : TOK_ID
      ;
M     :   /* empty */  {$$ = $-2; }
      ;
C     :  TOK_INT {$$ = $-1 + $1; } 
      ;