static bucket *errtoken = NULL;
static bucket *undeftoken = NULL;
static bucket *eoftoken = NULL;
+static bucket *axiom = NULL;
static symbol_list *
symbol_list_new (bucket *sym)
t = lex ();
}
-
/* grammar has been read. Do some checking */
- if (nsyms > MAXSHORT)
- fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
- MAXSHORT);
if (nrules == 0)
fatal (_("no rules in the input grammar"));
bp->value = nvars++;
}
+ /* Insert the initial rule, which line is that of the first rule
+ (not that of the start symbol):
+
+ axiom: %start EOF. */
+ p = symbol_list_new (axiom);
+ p->line = grammar->line;
+ p->next = symbol_list_new (startval);
+ p->next->next = symbol_list_new (eoftoken);
+ p->next->next->next = symbol_list_new (NULL);
+ p->next->next->next->next = grammar;
+ nrules += 1;
+ nitems += 3;
+ grammar = p;
+ startval = axiom;
+
+ if (nsyms > MAXSHORT)
+ fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
+ MAXSHORT);
+
ntokens = nsyms - nvars;
}
/* Initialize the symbol table. */
tabinit ();
+ /* Construct the axiom symbol. */
+ axiom = getsym ("$axiom");
+ axiom->class = nterm_sym;
+ axiom->value = nvars++;
+
/* Construct the error token */
errtoken = getsym ("error");
errtoken->class = token_sym;