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# confusion in finding first and follow in left recursive grammar

By : benmcrae
Date : November 18 2020, 11:13 AM
wish of those help Recently I faced the problem for finding first and follow , Firstly,you'll need to remove left-recursion leading to
code :
``````S -> cAd
A -> aA'
A' -> bA' | epsilon
``````
``````FIRST(A) = a         // as a is the only terminal nderived first from A.
``````
``````S -> AS'
S' -> AS' | epsilon
A -> a

FIRST(A) = a
FIRST(S) = a
FIRST(S') = {a,epsilon}.
``````

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## Left-factoring a non-left-recursive grammar to make it LL(1)

By : PatPawlowski
Date : March 29 2020, 07:55 AM
Hope that helps No, this grammar is not LL(1). At least, the last rules group is not left factored, since FIRST( Expr) and FIRST( Expr, Arglist) do interstect.

## How to find FIRST and FOLLOW sets of a recursive grammar?

By : user3364917
Date : March 29 2020, 07:55 AM
Any of those help Since FIRST and FOLLOW are (normally) recursive, it's useful to think of them as systems of equations to be solved; the solution can be achieved using a simple incremental algorithm consisting of repeatedly applying all the right hand sides until no set has changed during a cycle.
So let's take the FOLLOW relation for the given grammar:
code :
``````A → B | Cx | ε
B → C | yA
C → B | w | z
``````
``````FOLLOW(A) = FOLLOW(B) ∪ {\$}
FOLLOW(B) = FOLLOW(A) ∪ FOLLOW(C)
FOLLOW(C) = FOLLOW(B) ∪ {x}
``````
``````FOLLOW(A) = {} ∪ {\$} = {\$}
FOLLOW(B) = {\$} ∪ {} = {\$}
FOLLOW(C) = {\$} U {x} = {\$,x}
``````
``````FOLLOW(A) = {\$} ∪ {\$} = {\$}
FOLLOW(B) = {\$} ∪ {\$,x} = {\$,x}
FOLLOW(C) = {\$,x} U {x} = {\$,x}
``````
``````FOLLOW(A) = {\$,x} ∪ {\$} = {\$,x}
FOLLOW(B) = {\$} ∪ {\$,x} = {\$,x}
FOLLOW(C) = {\$,x} U {x} = {\$,x}
``````
``````FOLLOW(A) = {\$,x} ∪ {\$} = {\$,x}
FOLLOW(B) = {\$,x} ∪ {\$,x} = {\$,x}
FOLLOW(C) = {\$,x} U {x} = {\$,x}
``````

## Finding first and follow in a grammar

By : Ezequiel Netto
Date : March 29 2020, 07:55 AM
I hope this helps you . Your computation of the follow sets of L and L' is correct, so the answer you cite is either incorrect or applies to some other grammar.

## How to find FIRST and FOLLOW set of a recursive grammar?

By : Lily5912
Date : March 29 2020, 07:55 AM
it should still fix some issue Your work above (question) suggest that you are not good in basic concepts. So you can make use of the this tutorial.
Grammer :

## Confusion in finding follow of Gammar

By : Summergirl012
Date : March 29 2020, 07:55 AM
``````FOLLOW(A) of non-terminal A is the set of terminal symbols
``````             S->(L)
``````            L->L,S
``````           FOLLOW(L) = {),,}