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First and Follow Set of a given CFG

I have this CFG and there is a loop in it then how to make first and follow set of looped cfg as first sets are easy but having problem in follow sets

S -> iEtSS'|a
S' -> es
E -> b
Solution

  • I fixed the question as you might be asking answer for this question.

    S -> iEtSS'|a<br>
S' -> eS|eplison<br>
E -> b

    First

    First(S) -> {i, a}<br>
First(S') -> {e, eplison}<br>
First(E) -> {b}

    Follow

    Follow(S) -> {$, First(S')} -> {$, e}<br>
Follow(S') -> {Follow(S)} -> {$, e}<br>
Follow(E) -> {t}

    Even if there is a loop it possibly can't have more than above non terminal in Follow set.

    You may have seen loop as 

    Follow(S) -> {$, First(S'), Follow(S)}
->Follow(S) is because First(S') has eplison.