# CFG notation meaning in making LL parse table

I have problem of interpreting Context-free grammar notation in making LL(1) parse table.

To make LL(1) parse table. Two rules are shown below:

1. If A -> α is a production choice, and there is a derivation α =>* aβ, where a is a token, then add A -> α to the table entry M[A,a].

2. if A -> α is a production choice and there are derivations α =>* ε and S\$=>* βAaγ, where S is the start symbol and a is a token(or$), then add A -> α to the table entry M[A, a].

From the second theorem, I can't understand the meaning of S\$=>* βAaγ. I know the meaning of S =>* βAaγ, which means start symbol can be derived to βAaγ. But what's the meaning of S\$ =>* βAaγ ? (The only difference is the existence of \$)

• What does your textbook say about it? Dec 17, 2016 at 16:34
• What do you understand the meaning of α =>* aβ to be? Note that α represents a sequence of grammar symbols, since it is the right-hand side of some production.
– rici
Dec 17, 2016 at 19:58