start adding error message support

src/arobject.h

@@ -0,0 +1,52 @@
+#ifndef AROBJECT_H
+#define AROBJECT_H
+
+#include <gmp.h>
+#include "runtime/internals/dynamic_array_armem/darray_armem.h"
+
+typedef struct ArgonObject ArgonObject;  // forward declaration
+
+typedef enum ArgonType {
+  TYPE_NULL,
+  TYPE_BOOL,
+  TYPE_NUMBER,
+  TYPE_STRING,
+  TYPE_FUNCTION,
+  TYPE_NATIVE_FUNCTION,
+  TYPE_OBJECT,
+} ArgonType;
+
+struct string_struct {
+  char *data;
+  size_t length;
+};
+
+typedef struct Stack {
+  ArgonObject *scope;
+  struct Stack *prev;
+} Stack;
+
+struct argon_function_struct {
+  darray_armem bytecode;
+  Stack stack;
+  size_t number_of_parameters;
+  char **parameters;
+};
+
+// full definition of ArgonObject (no typedef again!)
+struct ArgonObject {
+  ArgonType type;
+  char *name;
+  ArgonObject *self;
+  ArgonObject *baseObject;
+  struct hashmap_GC *fields;
+  union {
+    mpq_t as_number;
+    bool as_bool;
+    struct string_struct as_str;
+    void *native_fn;
+    struct argon_function_struct argon_fn;
+  } value;
+};
+
+#endif // AROBJECT_H