In context-free grammar, a nonterminal is left recursive if the left-most symbol of one of its productions is itself.

Example: direct left-recursion

Example: indirect left-recursion

recursive descent parsers cannot handle grammar with left recursion but we can transform the grammar to eliminate left recursion. However, this will either introduce right associativity or complicate the grammar. 1

Footnotes

  1. Some problems of recursive descent parsers