2 /* Computation of FIRST stets */
4 #include "pgenheaders.h"
8 extern int Py_DebugFlag;
11 static void calcfirstset(grammar *, dfa *);
14 addfirstsets(grammar *g)
20 printf("Adding FIRST sets ...\n");
21 for (i = 0; i < g->g_ndfas; i++) {
23 if (d->d_first == NULL)
29 calcfirstset(grammar *g, dfa *d)
44 printf("Calculate FIRST set for '%s'\n", d->d_name);
48 if (d->d_first == dummy) {
49 fprintf(stderr, "Left-recursion for '%s'\n", d->d_name);
52 if (d->d_first != NULL) {
53 fprintf(stderr, "Re-calculating FIRST set for '%s' ???\n",
58 l0 = g->g_ll.ll_label;
59 nbits = g->g_ll.ll_nlabels;
60 result = newbitset(nbits);
62 sym = (int *)PyObject_MALLOC(sizeof(int));
64 Py_FatalError("no mem for new sym in calcfirstset");
66 sym[0] = findlabel(&g->g_ll, d->d_type, (char *)NULL);
68 s = &d->d_state[d->d_initial];
69 for (i = 0; i < s->s_narcs; i++) {
71 for (j = 0; j < nsyms; j++) {
72 if (sym[j] == a->a_lbl)
75 if (j >= nsyms) { /* New label */
76 sym = (int *)PyObject_REALLOC(sym,
77 sizeof(int) * (nsyms + 1));
80 "no mem to resize sym in calcfirstset");
81 sym[nsyms++] = a->a_lbl;
82 type = l0[a->a_lbl].lb_type;
83 if (ISNONTERMINAL(type)) {
84 d1 = PyGrammar_FindDFA(g, type);
85 if (d1->d_first == dummy) {
87 "Left-recursion below '%s'\n",
91 if (d1->d_first == NULL)
97 else if (ISTERMINAL(type)) {
98 addbit(result, a->a_lbl);
104 printf("FIRST set for '%s': {", d->d_name);
105 for (i = 0; i < nbits; i++) {
106 if (testbit(result, i))
107 printf(" %s", PyGrammar_LabelRepr(&l0[i]));