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From: Andy <borucki.andrzej@gmail.com>
Newsgroups: comp.compilers
Subject: How detect grammar not derive nonterminals ?
Date: Mon, 11 Sep 2023 08:58:17 -0700
Organization: Compilers Central
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Xref: csiph.com comp.compilers:3520

The simplest this case is grammar :
A -> A

but I have

A -> B
A -> b B
B -> A
B -> a A

it is trap for sequence generator. A->B->A->B->A....
How detect similar cases, especially without computing First and Follow sets ?