Types of SDD
1. S – attributed SDD or S attributed Grammar
L – attributed SDD or L attributed Grammar
2. S – attributed SDD – synthesized
L – attributed SDD – synthesized/ inherited
S – attributed SDD
A SDD that uses only synthesized attributes is called a S – attributed SDD
Ex: A -> BCD
A.S = B.S
A.S = C.S
A.S = D.S
Semantic actions are always placed at the right end of the production. It is also a postfix SDD.
Attributes are evaluated using bottom up passing
L – attributed SDD
A SDD that uses both synthesized and inherited attributes is called a L – attributed SDD but each inherited attribute is restricted to inherits from parent or left sibling
Ex: A – > BCD
C.S = A.S
C.S = B.S
C.S = D.S
Semantic actions are placed anywhere on the right hand side.
Attributes are evaluated by traversing parse tree depth first, left to right.
Reference Link