Work on dynamic variable

src/base.c

@@ -74,9 +74,7 @@ noreturn void signal_type_error(LispVal *obj, LispVal *typespec) {
 DEFINE_SYMBOL(nil, "nil");
 DEFINE_SYMBOL(t, "t");
 DEFINE_SYMBOL(unbound, "unbound");
-DEFINE_SYMBOL(lexical_environment, "lexical-environment");
-
-LispVal *Vlexical_environment;
+DEFVAR(lexical_environment, "lexical-environment", "", Qnil);
 
 DEFUN(id, "id", (LispVal * obj), "(id)", "") {
     // TODO not all values are handled here
@@ -112,10 +110,12 @@ DEFUN(make_symbol, "make-symbol", (LispVal * name), "(name)",
     obj->name = name;
     obj->function = Qnil;
     obj->plist = Qnil;
+    obj->value_type = SYMBOL_NORMAL;
     if (KEYWORDP(obj)) {
-        obj->value = obj;
+        obj->value.normal = obj;
+        obj->flags |= SYMBOL_CONST_VALUE;
     } else {
-        obj->value = Qunbound;
+        obj->value.normal = Qunbound;
     }
     return obj;
 }
@@ -161,6 +161,10 @@ DEFUN(set, "set", (LispVal * sym, LispVal *value), "(sym value)", "") {
 
 DEFUN(fset, "fset", (LispVal * sym, LispVal *value), "(sym value)", "") {
     CHECK_TYPE(sym, TYPE_SYMBOL);
+    if (CONST_FUNCTION_P(sym)) {
+        // TODO throw
+        abort();
+    }
     ((LispSymbol *) sym)->function = value;
     return value;
 }