Annotated Parse Trees
An annotated parse tree is a parse tree showing the value(s) of its attribute(s).
The attribute grammar (syntax-directed definitions) evaluating arithmetic expressions is given again on the right:
  Production Semantic Rules
1. <L> ::= <E> n Val(<L>) = Val(<E>)
2. <E> ::= <E1> + <T> Val(<E>) = Val(<E1>) + Val(<T>)
3. <E> ::= <T> Val(<E>) = Val(<T>)
4. <T> ::= <T1> * <F> Val(<T>) = Val(<T1>) × Val(<F>)
5. <T> ::= <F> Val(<T>) = Val(<F>)
6. <F> ::= ( <E> ) Val(<F>) = Val(<E>)
7. <F> ::= digit Val(<F>) = Lexval(digit)

The parse tree and annotated parse tree of the expression “3 * 5 + 4 n” are given as follows: