Left recursion
- 1. Transformation From Left Recursion To Non-Left Recursion 1
- 3. Objectives To Eliminate Left recursion by rewriting the offending production. The non-terminal A and its productions are said to be left recursive. To replace left recursive by non left recursive production. 3
- 4. What is Left Recursion? 4 A grammar is left-recursive if and only if there exists a nonterminal symbol that can derive to a sentential form with itself as the leftmost symbol . Symbolically, where indicates the operation of making one or more substitutions, and is any sequence of terminal and nonterminal symbols. Consider a nonterminal A with two productions A->A𝜶|β So, the nonterminal A and its production are said to be left recursive.
- 5. Left Recursion’s Formula There is a formal technique for eliminating left-recursion from productions . It’s a direct left recursion. Each rule which contains a left-recursive option A --> Aα|β Introduce a new nonterminal A' and rewrite the rule as A --> βA' A' --> αA' | ε 5
- 6. Working Procedure For implementing the code we use C language In the code segment, we declare char type variable. Here we use sprintf() and strtok() function. If we give a non-terminal left recursive expression as an input, then the recursive value is eliminating. Then a non-left recursive expression we get as an output. 6
- 7. Code : 7
- 8. Output : 8
- 9. 9