Learn Left recursion, Example of Left recursion
22 February, 2016
A grammar is left recursive if it goes to infinite loop.
Eg: S-> (L) |a
L->L,s|s
Eliminate the left recursion??
Ans: S->(L)|a
L->sL'
L'->,sL'| empty
Eg: S->A
A->Ad| Ae | Af|aB|aC
B->bBc|f
C->cC|c
Eliminate the left recursion??
Ans: S->A
A->aBA'|aCA'
A->dA'|eA|fA'|empty
B->bBC | f
C->cC\c
Elimination of left recursion is important because sometime Top down parsing goes to infinite loop because of left reursion .
Left Recursive grammar will enter into the infinite loop for those parser which will uses left most derivation(TDP).
