coly_lisp_object now dows not create new nil and t values anymore

Fixed an error where a nil value could not be used as the default
value as a keyword argument since coly_lisp_object would be invoked
before assigning nil as the default argument, producing a separate nil
value, which then fails the nil tests becase it lives in a different
location as Memory::nil.

src/error.cpp

@@ -14,7 +14,7 @@ proc create_error(const char* c_file_name, int c_file_line, Lisp_Object* type, S
     delete_error();
     debug_break();
 
-    visualize_lisp_machine();
+    // visualize_lisp_machine();
 
     using Globals::error;
     error = new(Error);

src/eval.cpp

@@ -24,11 +24,11 @@ proc apply_arguments_to_function(Lisp_Object* arguments, Function* function) ->
 
     if (arguments == Memory::nil)
         goto checks;
+
     // keyword arguments: use all given ones and keep track of the
     // added ones (array list), if end of parameters in encountered or
     // something that is not a keyword is encountered or a keyword
     // that is not recognized is encoutered, jump out of the loop.
-
     while (Memory::get_type(arguments->value.pair.first) == Lisp_Object_Type::Keyword) {
         // check if this one is even an accepted keyword
         bool accepted = false;
@@ -80,8 +80,9 @@ proc apply_arguments_to_function(Lisp_Object* arguments, Function* function) ->
         }
 
         // if not set it and then add it to the array list
-        try sym = Memory::get_or_create_lisp_object_symbol(arguments->value.pair.first->value.symbol.identifier),
-        define_symbol(sym, arguments->value.pair.rest->value.pair.first, new_env);
+        try sym = Memory::get_or_create_lisp_object_symbol(arguments->value.pair.first->value.symbol.identifier);
+        // NOTE(Felix): It seems we do not need to evaluate the argument here...
+        try define_symbol(sym, arguments->value.pair.rest->value.pair.first, new_env);
 
         append_to_array_list(read_in_keywords, arguments->value.pair.first->value.symbol.identifier);
 
@@ -257,9 +258,11 @@ proc parse_argument_list(Lisp_Object* arguments, Function* function) -> void {
                 // would be an error
                 next = next->value.pair.rest;
                 if (Memory::get_type(next) == Lisp_Object_Type::Pair) {
+                    Lisp_Object* ret;
+                    try_void ret = eval_expr(next->value.pair.first, function->parent_environment);
                     append_to_keyword_argument_list(function->keyword_arguments,
                                                     arguments->value.pair.first->value.symbol.identifier,
-                                                    next->value.pair.first);
+                                                    ret);
                     arguments = next->value.pair.rest;
                 } else {
                     create_parsing_error("Expecting a value after 'defaults-to'");
@@ -426,6 +429,7 @@ proc eval_expr(Lisp_Object* node, Environment* env) -> Lisp_Object* {
 proc is_truthy(Lisp_Object* expression, Environment* env) -> bool {
     Lisp_Object* result;
     try result = eval_expr(expression, env);
+
     return result != Memory::nil;
 }
 

src/memory.cpp

@@ -283,6 +283,9 @@ namespace Memory {
     }
 
     proc copy_lisp_object(Lisp_Object* n) -> Lisp_Object* {
+        if (n == nil || n == t)
+            return n;
+
         Lisp_Object* target;
         try target = create_lisp_object();
         *target = *n;

src/testing.cpp

@@ -635,6 +635,7 @@ proc run_all_tests() -> bool {
 
     printf("\n-- Test Files --\n");
 
+    invoke_test_script("evaluation_of_default_args");
     invoke_test_script("lexical_scope");
     invoke_test_script("class_macro");
     invoke_test_script("sicp");