1 files changed, 92 insertions, 0 deletions
diff --git a/eval.c b/eval.c
new file mode 100644
index 0000000..9e1e946
--- /dev/null
+++ b/eval.c
@@ -0,0 +1,92 @@
+#include <string.h>
+#include <stdio.h>
+
+#include "types.h"
+
+typedef struct val {
+	type t;
+	char *name;
+	union {
+		int i;
+	};
+} val;
+
+val *vars[4096];
+int varcount = 0;
+
+values *eval(ast *a);
+
+values *getval(ast *a, int index, type t) { 
+	values *tmp;
+	if (t == INT && a->vals->ts[index] == INT)
+		return a->vals;
+	else if  ((tmp = eval(a->vals->as[index]))->ts[0] == t)
+		return tmp;
+	else
+		fprintf(stderr, "expected value, but got nothing\n");
+}
+
+void checkcount(ast *a, int argc) {
+	if (a->vals->argc != argc)
+		fprintf(stderr, "incorrect number of args given!\n");
+}
+
+values *eval(ast *a) {
+	values *v = malloc(sizeof(values));
+
+	if (strcmp(a->fname, "print") == 0) {
+		checkcount(a, 1);
+		printf("%d\n", getval(a, 0, INT)->is[0]);
+		return NULL;
+	} 
+
+	else if (strcmp(a->fname, "set") == 0) {
+		checkcount(a, 2);
+		printf("%d\n", getval(a, 0, INT)->is[0]);
+		return NULL;
+	} 
+
+	else if (strcmp(a->fname, "+") == 0) {
+		v->is[0] = getval(a, 0, INT)->is[0];
+		for (int i = 1; i < a->vals->argc; i++) 
+			v->is[0] += getval(a, i, INT)->is[i];
+
+		v->ts[0] = INT;
+		v->argc++;
+	}
+	else if (strcmp(a->fname, "-") == 0) {
+		if (a->vals->argc == 1) 
+			v->is[0] = -getval(a, 0, INT)->is[0];
+		else {
+			v->is[0] = getval(a, 0, INT)->is[0];
+			for (int i = 1; i < a->vals->argc; i++) 
+				v->is[0] -= getval(a, i, INT)->is[i];
+		}
+
+		v->ts[0] = INT;
+		v->argc++;
+	}
+	else if (strcmp(a->fname, "*") == 0) {
+		v->is[0] = getval(a, 0, INT)->is[0]; 
+		for (int i = 1; i < a->vals->argc; i++) 
+			v->is[0] *= getval(a, i, INT)->is[i];
+
+		v->ts[0] = INT;
+		v->argc++;
+	}
+	else if (strcmp(a->fname, "/") == 0) {
+		v->is[0] = getval(a, 0, INT)->is[0];
+		for (int i = 1; i < a->vals->argc; i++) 
+			v->is[0] /= getval(a, i, INT)->is[i];
+
+		v->ts[0] = INT;
+		v->argc++;
+	}
+	else if (strcmp(a->fname, "%") == 0) {
+		v->is[0] = getval(a, 0, INT)->is[0] % getval(a, 1, INT)->is[1];
+		v->ts[0] = INT;
+		v->argc++;
+	}
+
+	return v;
+}