Introduction

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Try to perform the elimination of left recursion, the input grammar should have no cycles or ϵ-productions.

Supported grammars

• A -> A c | A a d | b d | ϵ
  (All tokens must be separated by space characters)
• A -> A c
     | A a d
     | b d
     | ϵ
• S -> A a | b
  A -> A c | S d | ϵ
• (Copy ϵ to input if needed)

Examples

• S -> S S + | S S * | a
• S -> 0 S 1 | 0 1
• S -> + S S | * S S | a
• S -> S ( S ) S | ϵ
• S -> S + S | S S | ( S ) | S * | a
• S -> ( L ) | a L -> L , S | S
• S -> a S b S | b S a S | ϵ
• bexpr -> bexpr or bterm | bterm
  bterm -> bterm and bfactor | bfactor
  bfactor -> not bfactor | ( bexpr ) | true | false