Initial code commit.

src/value.h

@@ -0,0 +1,39 @@
+#ifndef FUN_VALUE_H
+#define FUN_VALUE_H
+
+#include <inttypes.h>
+
+struct Bytecode; /* forward */
+
+typedef enum {
+    VAL_INT,
+    VAL_STRING,
+    VAL_FUNCTION,
+    VAL_NIL
+} ValueType;
+
+typedef struct {
+    ValueType type;
+    union {
+        int64_t i;
+        char *s;
+        struct Bytecode *fn;
+    };
+} Value;
+
+/* constructors / helpers */
+Value make_int(int64_t v);
+Value make_string(const char *s);
+Value make_function(struct Bytecode *fn);
+Value make_nil(void);
+
+/* copy (deep for strings), free (free string only) */
+Value copy_value(const Value *v);
+void free_value(Value v);
+
+/* utilities */
+void print_value(const Value *v);
+int value_is_truthy(const Value *v);
+
+#endif
+