How can I eliminate left recursion in the following grammar?

Question

Here's the grammar, which is supposed to describe a language of nested braces with commas as delimiters:

L ::= {L} | L,L |

A few more examples of strings I'd expect the grammar to accept and reject:

Accept:

{,{,,{,}},,{,}}
{{{{}}}}
{,{}}

Reject:

{}{}
{,{}{}}
{{},{}

Answer 1

First of all, that grammar won't accept your first example, since it requires the commas to be after the close brace and before the open brace. I would suggest to re-write it as

L::= {L} | ,L

This won't get rid of the left recursion, but it will at least match your acceptable answers.