Syntax Analysis9
For the grammar below, a partial LL(1) parsing table is also presented along with the grammar. Entries that need to be filled are indicated as E1, E2, and E3. ε is the empty string, $ indicates end of input, and | separates alternate right hand sides of productions. S → a A b B|b A a B|ε A → S B → S a b $ S E1 E2 S → ε A A → S A → S error B B → S B → S E3
0. The FIRST and FOLLOW sets for the nonterminals A and B are
- A
FIRST (A) = {a, b, ε} = FIRST (B), FOLLOW (A) = {a, b} FOLLOW (B) = {a, b, $}
- B
FIRST (A) = {a, b, $} FIRST (B) = {a, b, ε} FOLLOW (A) = {a, b} FOLLOW(B) = {$}
- C
FIRST (A) = {a, b, ε} = FIRST (B), FOLLOW (A) = {a, b} FOLLOW (B) = $
- D
FIRST (A) = {a, b} = FIRST (B) FOLLOW (A) = {a, b} FOLLOW (B) = {a, b}
- Option : A
- Explanation : FIRST(S) = {a, b, ε} FIRST(A) = FIRST(S) = {a, b, ε} FIRST(B) = FIRST(S) = {a, b, ε} FOLLOW (A) = {b, a} FOLLOW (S) = {$} U FOLLOW (A) = {b, a, $} FOLLOW (B) = FOLLOW (S) = {b, a, $}
