add functions to bytecode and continuing working on runtime objects

src/parser/function/function.h

@@ -0,0 +1,17 @@
+#ifndef FUNCTION_H
+#define FUNCTION_H
+#include "../../lexer/token.h" // for Token
+#include "../parser.h"
+
+typedef struct {
+  char * name;
+  DArray parameters;
+  ParsedValue *body;
+} ParsedFunction;
+
+ParsedValue *create_parsed_function(char *name, DArray parameters,
+                                  ParsedValue *body);
+
+void free_function(void *ptr);
+
+#endif // FUNCTION_H