little cleanup for c-macro calls

src/built_ins.cpp

@@ -163,8 +163,6 @@ namespace Slime {
             profile_with_name("(apply)");
             using namespace Globals::Current_Execution;
 
-            --cs.next_index;
-            --ams.next_index;
             Lisp_Object* args = pcs[--pcs.next_index];
             try_void assert_list_length(args, 2);
 
@@ -224,10 +222,9 @@ namespace Slime {
         {
             profile_with_name("(eval)");
             using namespace Globals::Current_Execution;
-            // TODO(Felix): ams index should be decremented in
-            // eval_expr when calling the macro
-            --ams.next_index;
-            cs.data[cs.next_index-1] = pcs[--pcs.next_index]->value.pair.first;
+            // we know cs.data[cs.next_index] is allocated because the
+            // macro cal lwas there just before
+            cs.data[cs.next_index++] = pcs[--pcs.next_index]->value.pair.first;
             (nass.end()-1)->append(NasAction::Eval);
             (nass.end()-1)->append(NasAction::Eval);
 
@@ -238,8 +235,6 @@ namespace Slime {
         {
             profile_with_name("(begin)");
             using namespace Globals::Current_Execution;
-            --cs.next_index;
-            --ams.next_index;
             Lisp_Object* args = pcs[--pcs.next_index];
             int length = list_length(args);
             cs.reserve(length);
@@ -263,7 +258,6 @@ namespace Slime {
                |          | -> |   <then>  |
                |   <if>   |    |   <else>  |
                |   ....   |    |   ......  | */
-            --ams.next_index;
             Lisp_Object* args = pcs.data[--pcs.next_index];
             Lisp_Object* test = args->value.pair.first;
             args = args->value.pair.rest;
@@ -274,7 +268,7 @@ namespace Slime {
             Lisp_Object* alternative = args->value.pair.first;
             args = args->value.pair.rest;
             try_void assert_type(args, Lisp_Object_Type::Nil);
-            --cs.next_index;
+
             cs.append(alternative);
             cs.append(consequence);
             cs.append(test);
@@ -292,8 +286,7 @@ namespace Slime {
             // and a NasAction.
             profile_with_name("(define)");
             using namespace Globals::Current_Execution;
-            --cs.next_index;
-            --ams.next_index;
+
             Lisp_Object* form    = pcs.data[--pcs.next_index];
             Lisp_Object* definee = form->value.pair.first;
             form = form->value.pair.rest;

src/eval.cpp

@@ -395,6 +395,8 @@ namespace Slime {
                 case Lisp_Object_Type::Function: {
                     if(pc->value.function->is_c) {
                         if (pc->value.function->type.c_function_type == C_Function_Type::cMacro) {
+                            --cs.next_index;  // remove the macro call from cs
+                            --ams.next_index; // remove the apply marker for the macro
                             try pc->value.function->body.c_macro_body();
                         } else if (pc->value.function->type.c_function_type == C_Function_Type::cSpecial)
                         {