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Commit | Line | Data |
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c8042e10 DM |
1 | \r |
2 | /* Computation of FIRST stets */\r | |
3 | \r | |
4 | #include "pgenheaders.h"\r | |
5 | #include "grammar.h"\r | |
6 | #include "token.h"\r | |
7 | \r | |
8 | extern int Py_DebugFlag;\r | |
9 | \r | |
10 | /* Forward */\r | |
11 | static void calcfirstset(grammar *, dfa *);\r | |
12 | \r | |
13 | void\r | |
14 | addfirstsets(grammar *g)\r | |
15 | {\r | |
16 | int i;\r | |
17 | dfa *d;\r | |
18 | \r | |
19 | if (Py_DebugFlag)\r | |
20 | printf("Adding FIRST sets ...\n");\r | |
21 | for (i = 0; i < g->g_ndfas; i++) {\r | |
22 | d = &g->g_dfa[i];\r | |
23 | if (d->d_first == NULL)\r | |
24 | calcfirstset(g, d);\r | |
25 | }\r | |
26 | }\r | |
27 | \r | |
28 | static void\r | |
29 | calcfirstset(grammar *g, dfa *d)\r | |
30 | {\r | |
31 | int i, j;\r | |
32 | state *s;\r | |
33 | arc *a;\r | |
34 | int nsyms;\r | |
35 | int *sym;\r | |
36 | int nbits;\r | |
37 | static bitset dummy;\r | |
38 | bitset result;\r | |
39 | int type;\r | |
40 | dfa *d1;\r | |
41 | label *l0;\r | |
42 | \r | |
43 | if (Py_DebugFlag)\r | |
44 | printf("Calculate FIRST set for '%s'\n", d->d_name);\r | |
45 | \r | |
46 | if (dummy == NULL)\r | |
47 | dummy = newbitset(1);\r | |
48 | if (d->d_first == dummy) {\r | |
49 | fprintf(stderr, "Left-recursion for '%s'\n", d->d_name);\r | |
50 | return;\r | |
51 | }\r | |
52 | if (d->d_first != NULL) {\r | |
53 | fprintf(stderr, "Re-calculating FIRST set for '%s' ???\n",\r | |
54 | d->d_name);\r | |
55 | }\r | |
56 | d->d_first = dummy;\r | |
57 | \r | |
58 | l0 = g->g_ll.ll_label;\r | |
59 | nbits = g->g_ll.ll_nlabels;\r | |
60 | result = newbitset(nbits);\r | |
61 | \r | |
62 | sym = (int *)PyObject_MALLOC(sizeof(int));\r | |
63 | if (sym == NULL)\r | |
64 | Py_FatalError("no mem for new sym in calcfirstset");\r | |
65 | nsyms = 1;\r | |
66 | sym[0] = findlabel(&g->g_ll, d->d_type, (char *)NULL);\r | |
67 | \r | |
68 | s = &d->d_state[d->d_initial];\r | |
69 | for (i = 0; i < s->s_narcs; i++) {\r | |
70 | a = &s->s_arc[i];\r | |
71 | for (j = 0; j < nsyms; j++) {\r | |
72 | if (sym[j] == a->a_lbl)\r | |
73 | break;\r | |
74 | }\r | |
75 | if (j >= nsyms) { /* New label */\r | |
76 | sym = (int *)PyObject_REALLOC(sym,\r | |
77 | sizeof(int) * (nsyms + 1));\r | |
78 | if (sym == NULL)\r | |
79 | Py_FatalError(\r | |
80 | "no mem to resize sym in calcfirstset");\r | |
81 | sym[nsyms++] = a->a_lbl;\r | |
82 | type = l0[a->a_lbl].lb_type;\r | |
83 | if (ISNONTERMINAL(type)) {\r | |
84 | d1 = PyGrammar_FindDFA(g, type);\r | |
85 | if (d1->d_first == dummy) {\r | |
86 | fprintf(stderr,\r | |
87 | "Left-recursion below '%s'\n",\r | |
88 | d->d_name);\r | |
89 | }\r | |
90 | else {\r | |
91 | if (d1->d_first == NULL)\r | |
92 | calcfirstset(g, d1);\r | |
93 | mergebitset(result,\r | |
94 | d1->d_first, nbits);\r | |
95 | }\r | |
96 | }\r | |
97 | else if (ISTERMINAL(type)) {\r | |
98 | addbit(result, a->a_lbl);\r | |
99 | }\r | |
100 | }\r | |
101 | }\r | |
102 | d->d_first = result;\r | |
103 | if (Py_DebugFlag) {\r | |
104 | printf("FIRST set for '%s': {", d->d_name);\r | |
105 | for (i = 0; i < nbits; i++) {\r | |
106 | if (testbit(result, i))\r | |
107 | printf(" %s", PyGrammar_LabelRepr(&l0[i]));\r | |
108 | }\r | |
109 | printf(" }\n");\r | |
110 | }\r | |
111 | \r | |
112 | PyObject_FREE(sym);\r | |
113 | }\r |