grammar Example_4_4_solution;

/* 
partially solved
left factorization and  leftmost nonterminal expansion used

check the grammar by menu Grammar -> Check Grammar (CTRL+r)
*/
options {
k=1;
}

init 	:	a '\n';

a
	:   'a' a_after_a | 'b' a_after_b 
	;

a_after_a
	:   'b' b | 'c' a_after_ac
	;

a_after_ac
	:    c | 'd' b 
	;

a_after_b
	:    'b' a_after_bb | 'c' b c 'b' 
	;

a_after_bb
	:    'a' a | 'b' a_after_bbb
	;
	
a_after_bbb
	:    'a' a_after_bbba | //epsilon
	;

a_after_bbba
	:     b 'b'| 'd' c 'b'
	;

b
    	: 'b' 'b' 'a' b_after_bba | 'c' b c 
	;   	

b_after_bba
        : b | 'd' c 
        ;

c
    	: 'a' a | 'b' 
	;