1; ---------------------------------------------------------------------------
 2;
 3;  GrammarS=SaSb,EPSILON.dat
 4;
 5; ---------------------------------------------------------------------------
 6;
 7;  The sample grammar with epsilon productions,
 8;
 9;      S -> S a S b | EPSILON
10;
11;  from page 386 and 389-90 of
12;
13;  THE THEORY OF PARSING, TRANSLATION AND COMPILING, VOL. 1: PARSING,
14;  Alfred V. Aho and Jeffrey D. Ullman, Addison-Wesley, 1986.
15;
16
17; Productions.
18
19( 
20   (S -> S |a| S |b| / EPSILON)
21)
22
23
24; Terminal symbols, put between || delimiters to suppress LISP conversion to upper case upon read.
25
26( |a| |b| )