Parse tree for real x, y, z

Dependence of attributes in an inherited attribute system. The value of in (an inherited attribute) at the three L nodes gives the type of the three identifiers x , y and z . These are determined by computing the value of the attribute T.type at the left child of the root and then valuating L.in top down at the three L nodes in the right subtree of the root. At each L node the procedure addtype is called which inserts the type of the identifier to its entry in the symbol table. The figure also shows the dependence graph which is introduced later.