1 files changed, 37 insertions, 0 deletions
diff --git a/eval.c b/eval.c
new file mode 100644
index 0000000..02b85f1
--- /dev/null
+++ b/eval.c
@@ -0,0 +1,37 @@
+#include <stdlib.h>
+#include "eval.h"
+#include "parse.h"
+char just_is_sound(prop_t prop, just_t just, lineSet_t lines) {
+	prop_t a;
+	prop_t b;
+	if (!prop.isSimple) {
+		a = *prop.propA;
+		b = *prop.propB;
+	}
+	prop_t w;
+	prop_t x;
+	prop_t y;
+	prop_t z;
+	if (just.referencesCount > 0) {
+		w = lines.lines[just.references[0] - 1].proposition;
+	}
+	if (just.referencesCount > 1) {
+		x = lines.lines[just.references[1] - 1].proposition;
+	}
+	if (just.referencesCount > 2) {
+		y = lines.lines[just.references[2] - 1].proposition;
+	}
+	if (just.referencesCount > 3) {
+		z = lines.lines[just.references[3] - 1].proposition;
+	}
+	switch (just.rule) {
+		case PREMISE_R:
+			return 1;
+		case ASSUMPTION_R:
+			return 1;
+		case CONJUNCT_INTRO:
+			return (peq(a, w) && peq(b, x)) || (peq(a, x) && peq(b, w));
+		default:
+			return 0;
+	}
+}