expose frame-previous, once again

* libguile/frames.h:
* libguile/frames.c (scm_frame_previous): Rename from scm_c_frame_prev,
  and expose to Scheme. Skip boot frames.

* libguile/stacks.c (stack_depth, narrow_stack, scm_make_stack)
  (scm_stack_ref): Adjust for scm_frame_previous skipping boot frames.

diff --git a/libguile/frames.c b/libguile/frames.c
index e38fc00..80c556b 100644 (file)
--- a/libguile/frames.c
+++ b/libguile/frames.c
@@ -264,23 +264,34 @@ SCM_DEFINE (scm_frame_dynamic_link, "frame-dynamic-link", 1, 0, 0,
 }
 #undef FUNC_NAME
 
-extern SCM
-scm_c_frame_prev (SCM frame)
+SCM_DEFINE (scm_frame_previous, "frame-previous", 1, 0, 0,
+           (SCM frame),
+           "")
+#define FUNC_NAME s_scm_frame_previous
 {
   SCM *this_fp, *new_fp, *new_sp;
+
+  SCM_VALIDATE_VM_FRAME (1, frame);
+
+ again:
   this_fp = SCM_VM_FRAME_FP (frame);
   new_fp = SCM_FRAME_DYNAMIC_LINK (this_fp);
   if (new_fp) 
     { new_fp = RELOC (frame, new_fp);
       new_sp = SCM_FRAME_LOWER_ADDRESS (this_fp) - 1;
-      return scm_c_make_frame (SCM_VM_FRAME_STACK_HOLDER (frame),
-                               new_fp, new_sp,
-                               SCM_FRAME_RETURN_ADDRESS (this_fp),
-                               SCM_VM_FRAME_OFFSET (frame));
+      frame = scm_c_make_frame (SCM_VM_FRAME_STACK_HOLDER (frame),
+                                new_fp, new_sp,
+                                SCM_FRAME_RETURN_ADDRESS (this_fp),
+                                SCM_VM_FRAME_OFFSET (frame));
+      if (SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
+        goto again;
+      else
+        return frame;
     }
   else
     return SCM_BOOL_F;
 }
+#undef FUNC_NAME
 
 \f
 void

diff --git a/libguile/frames.h b/libguile/frames.h
index 45ade5a..0636fe8 100644 (file)
--- a/libguile/frames.h
+++ b/libguile/frames.h
@@ -120,8 +120,7 @@ SCM_API SCM scm_frame_instruction_pointer (SCM frame);
 SCM_API SCM scm_frame_return_address (SCM frame);
 SCM_API SCM scm_frame_mv_return_address (SCM frame);
 SCM_API SCM scm_frame_dynamic_link (SCM frame);
-
-SCM_API SCM scm_c_frame_prev (SCM frame);
+SCM_API SCM scm_frame_previous (SCM frame);
 
 SCM_INTERNAL void scm_bootstrap_frames (void);
 SCM_INTERNAL void scm_init_frames (void);

diff --git a/libguile/stacks.c b/libguile/stacks.c
index 60f0159..61b7be3 100644 (file)
--- a/libguile/stacks.c
+++ b/libguile/stacks.c
@@ -69,9 +69,8 @@ stack_depth (SCM frame, SCM *fp)
   long n;
   /* count frames, skipping boot frames */
   for (; scm_is_true (frame) && SCM_VM_FRAME_FP (frame) > fp;
-       frame = scm_c_frame_prev (frame))
-    if (!SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
-      ++n;
+       frame = scm_frame_previous (frame))
+    ++n;
   return n;
 }
 
@@ -112,7 +111,7 @@ narrow_stack (SCM stack, long inner, SCM inner_key, long outer, SCM outer_key)
       for (; inner && len; --inner)
         {
           len--;
-          frame = scm_c_frame_prev (frame);
+          frame = scm_frame_previous (frame);
         }
     }
   else
@@ -122,7 +121,7 @@ narrow_stack (SCM stack, long inner, SCM inner_key, long outer, SCM outer_key)
         {
           SCM proc = scm_frame_procedure (frame);
           len--;
-          frame = scm_c_frame_prev (frame);
+          frame = scm_frame_previous (frame);
           if (scm_is_eq (proc, inner_key))
             break;
         }
@@ -231,6 +230,11 @@ SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
       /* not reached */
     }
 
+  /* FIXME: is this even possible? */
+  if (scm_is_true (frame)
+      && SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
+    frame = scm_frame_previous (frame);
+  
   if (scm_is_false (frame))
     return SCM_BOOL_F;
 
@@ -351,11 +355,7 @@ SCM_DEFINE (scm_stack_ref, "stack-ref", 2, 0, 0,
   c_index = scm_to_unsigned_integer (index, 0, SCM_STACK_LENGTH(stack)-1);
   frame = SCM_STACK_FRAME (stack);
   while (c_index--)
-    {
-      frame = scm_c_frame_prev (frame);
-      while (SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
-        frame = scm_c_frame_prev (frame);
-    }
+    frame = scm_frame_previous (frame);
   return frame;
 }
 #undef FUNC_NAME