In case of syntax errors in the input, yyref tries to generate as much information as it can.
The output consists of a number listing of the header and rules part, followed by the cross-reference:
1 : %{
2 : # include <ctype.h>
3 : %}
4 :
5 :
6 : /******************************************************* 7 : * *
8 : * Date : Fri Jul 4 00:50:04 BST 1986 *
9 : * *
10 : *****************************************************/
11 :
12 : %token IDENTIFIER START_TOKEN NUMBER
13 :
14 : %start small
15 :
16 : %%
17 :
18 : small
19 : : start middle
20 : {
21 : printf("nMiddle");
22 : yyclearin;
23 : return(0);
24 : }
25 : end postamble
26 : ;
27 :
28 : start
29 : : /* empty */
30 : | START_TOKEN
31 : ;
32 :
33 : middle
34 : :
35 : ;
36 :
37 : middle
38 : : MID_TOKEN
39 : | /* empty */
40 : ;
41 :
42 : %%
~~~~~~~ *18 , never occurs on rhs of rule - start rule?
~~~~~~~ *28 , 19
~~~~~~~ *33 , *37, 19
~~~~~~~ is not declared - token??, 25
~~~~~~~ is not declared - token??, 25
~~~~~~~ is not declared - token??, 30
~~~~~~~ is not declared - token??, 38
End of X-ref
~~~~~~~~~~~~