CODEWITHSUNDEEP
grammarcomputation-theory
Someone
Someone

Reputation: 1

Difference between grammar rules

Say there are two grammar rules

Rule 1 B -> aB | cB

and

Rule 2 B -> Ba | Bc

I'm a bit confused as the difference of these two. Would rule 1's expression be (a+c)* ? Then what would Rule 2's expression be?

Upvotes: 0

Views: 38

Answers (1)

rici
rici

Reputation: 241971

Both of those grammars yield the empty language since there is no non-recursive rule, so no sentence consisting only of terminals can be derived.

If you add the production B→ε, both grammars would yield the same language, equivalent to the regular expression (a+c)*. However, the parse trees produced by the parse would be quite different.

Upvotes: 1

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