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-rw-r--r--libnormalform_nif.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/libnormalform_nif.c b/libnormalform_nif.c
new file mode 100644
index 0000000..5b2ae24
--- /dev/null
+++ b/libnormalform_nif.c
@@ -0,0 +1,228 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+
+LIBNORMALFORM_SENTENCE *
+(libnormalform_nif)(LIBNORMALFORM_SENTENCE **xs)
+{
+ LIBNORMALFORM_SENTENCE *x, *ret;
+ int inv;
+
+ /* 0 ↚ x = x, but 1 ↚ x = 0 */
+ ret = libnormalform_false();
+
+ for (; (x = *xs); xs++) {
+ if (!ret) {
+ /* error handling */
+ libnormalform_free(x);
+
+ } else if (ret->type == TYPE_TRUE || x->type == TYPE_FALSE) {
+ set_to_false:
+ /* 1 ↚ x = 0 */
+ /* x ↚ 0 = 0 */
+ libnormalform_free(x);
+ libnormalform_free(ret);
+ ret = libnormalform_false();
+
+ } else if (ret->type == TYPE_FALSE) {
+ set_to_x:
+ /* 0 ↚ x = x */
+ libnormalform_free(ret);
+ ret = x;
+
+ } else if (ret->equals(ret, x, &inv)) {
+ if (!inv) {
+ /* x ↚ x = 0 */
+ goto set_to_false;
+
+ } else {
+ /* ¬x ↚ x = x (0 ↚ 1 = 1, 1 ↚ 0 = 0) */
+ goto set_to_x;
+ }
+
+ } else {
+ /* l ↚ r = ¬(l ← r) = ¬(r → l) = ¬¬(r ∧ ¬l) = r ∧ ¬l = ¬l ∧ r */
+ ret = libnormalform_and2(libnormalform_not(ret), x);
+ }
+ }
+
+ return ret;
+}
+
+
+#else
+
+
+#define NIF(...) LIBNORMALFORM_NIF(__VA_ARGS__)
+
+
+int
+main(void)
+{
+ TEST_BEGIN;
+
+ struct libnormalform_variable var1, var2, var3;
+ LIBNORMALFORM_SENTENCE *a, *b, *v1, *v2, *v3;
+ LIBNORMALFORM_SENTENCE *ts, *fs;
+
+ ASSUME(v1 = libnormalform_variable(&var1));
+ ASSUME(v2 = libnormalform_variable(&var2));
+ ASSUME(v3 = libnormalform_variable(&var3));
+ ASSUME(ts = libnormalform_true());
+ ASSUME(fs = libnormalform_false());
+
+#ifdef USE_CHECKED_VERSION
+ errno = 0;
+ ASSERT(!NIF(REF(v1), NULL) && errno == 0);
+ errno = 1;
+ ASSERT(!NIF(REF(v1), NULL) && errno == 1);
+ errno = 0;
+ ASSERT(!NIF(NULL, REF(v1)) && errno == 0);
+ errno = 1;
+ ASSERT(!NIF(NULL, REF(v1)) && errno == 1);
+ errno = 0;
+ ASSERT(!NIF(NULL, NULL) && errno == 0);
+ errno = 1;
+ ASSERT(!NIF(NULL, NULL) && errno == 1);
+#endif
+
+#define T REF(ts)
+#define F REF(fs)
+#define TV LIBNORMALFORM_TRUE
+#define FV LIBNORMALFORM_FALSE
+
+#define ASSERT_CONST(VALUE, ...)\
+ do {\
+ ASSUME(a = NIF(__VA_ARGS__));\
+ ASSERT(a->type == TYPE_##VALUE);\
+ libnormalform_free(a);\
+ } while (0)
+
+#define ASSERT_EVAL2(VALUE, V1, V2)\
+ do {\
+ ASSUME(a = NIF(REF(v1), REF(v2)));\
+ ASSERT(a->type != TYPE_TRUE && a->type != TYPE_FALSE);\
+ var1.value = V1##V;\
+ var2.value = V2##V;\
+ ASSERT(libnormalform_evaluate(a) == (int)LIBNORMALFORM_##VALUE);\
+ libnormalform_free(a);\
+ } while (0)
+
+#ifndef USE_TWO
+
+#if defined(__GNUC__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wformat"
+#endif
+
+ ASSERT_CONST(FALSE); /* NIF () -> FALSE */
+
+#if defined(__GNUC__)
+# pragma GCC diagnostic pop
+#endif
+
+ ASSERT_CONST(TRUE, T); /* NIF (TRUE) -> TRUE */
+ ASSERT_CONST(FALSE, F); /* NIF (FALSE) -> FALSE */
+
+#endif
+
+ ASSERT_CONST(FALSE, F, F); /* NIF (FALSE, FALSE) -> FALSE */
+ ASSERT_CONST(TRUE, F, T); /* NIF (FALSE, TRUE) -> TRUE */
+ ASSERT_CONST(FALSE, T, F); /* NIF (TRUE, FALSE) -> FALSE */
+ ASSERT_CONST(FALSE, T, T); /* NIF (TRUE, TRUE) -> FALSE */
+
+ ASSERT_EVAL2(FALSE, F, F); /* NIF (var(FALSE), var(FALSE)) => FALSE */
+ ASSERT_EVAL2(TRUE, F, T); /* NIF (var(FALSE), var(TRUE)) => TRUE */
+ ASSERT_EVAL2(FALSE, T, F); /* NIF (var(TRUE), var(FALSE)) => FALSE */
+ ASSERT_EVAL2(FALSE, T, T); /* NIF (var(TRUE), var(TRUE)) => FALSE */
+
+#ifndef USE_TWO
+
+ /* NIF (x) -> x */
+ ASSUME(a = NIF(REF(v1)));
+ ASSERT(a == v1);
+ ASSERT(a->refcount == 2);
+ libnormalform_free(a);
+
+#endif
+
+ /* NIF (x, TRUE) -> NOT x */
+ ASSUME(a = NIF(REF(v1), T));
+ ASSERT_INVEQUAL(a, v1);
+ libnormalform_free(a);
+
+ /* NIF (TRUE, x) -> FALSE */
+ ASSUME(a = NIF(T, REF(v1)));
+ ASSERT(a->type == TYPE_FALSE);
+ libnormalform_free(a);
+
+ /* NIF (x, FALSE) -> FALSE */
+ ASSUME(a = NIF(REF(v1), F));
+ ASSERT(a->type == TYPE_FALSE);
+ libnormalform_free(a);
+
+ /* NIF (FALSE, x) -> x */
+ ASSUME(a = NIF(F, REF(v1)));
+ ASSERT_EQUAL(a, v1);
+ libnormalform_free(a);
+
+ /* NIF (x, x) -> FALSE */
+ ASSUME(a = NIF(REF(v1), REF(v1)));
+ ASSERT(a->type == TYPE_FALSE);
+ libnormalform_free(a);
+
+ /* NIF (NOT x, x) -> x */
+ ASSUME(a = libnormalform_not(REF(v1)));
+ ASSUME(a = NIF(a, REF(v1)));
+ ASSERT_EQUAL(a, v1);
+ ASSERT(a == v1);
+ libnormalform_free(a);
+
+ /* NIF (x, y) -> AND (NOT x, y) */
+ ASSUME(b = libnormalform_not(REF(v1)));
+ ASSUME(b = libnormalform_and2(b, REF(v2)));
+ ASSUME(a = NIF(REF(v1), REF(v2)));
+ ASSERT_EQUAL(a, b);
+ libnormalform_free(a);
+ libnormalform_free(b);
+
+#ifndef USE_TWO
+
+ /* NIF (x, y, z) -> AND (NOT AND (NOT x, y), z) */
+ ASSUME(b = libnormalform_not(REF(v1)));
+ ASSUME(b = libnormalform_nand2(b, REF(v2)));
+ ASSUME(b = libnormalform_and2(b, REF(v3)));
+ ASSUME(a = NIF(REF(v1), REF(v2), REF(v3)));
+ ASSERT_EQUAL(a, b);
+ libnormalform_free(a);
+ libnormalform_free(b);
+
+ /* NIF (x, y) -> independence from NIF (y, x) */
+ ASSUME(a = NIF(REF(v1), REF(v2)));
+ ASSUME(b = NIF(REF(v2), REF(v1)));
+ ASSERT_NOTEQUAL(a, b);
+ libnormalform_free(a);
+ libnormalform_free(b);
+
+#endif
+
+#undef T
+#undef F
+#undef TV
+#undef FV
+
+#undef ASSERT_CONST
+#undef ASSERT_EVAL2
+
+ libnormalform_free(v1);
+ libnormalform_free(v2);
+ libnormalform_free(v3);
+ libnormalform_free(ts);
+ libnormalform_free(fs);
+
+ TEST_END;
+}
+
+
+#endif