SCM
nested_property_revert_alist (SCM alist, SCM prop_path)
{
- int copy_count = 0;
- bool drop = false;
assert(scm_is_pair (prop_path));
SCM wanted_sym = scm_car (prop_path);
{
SCM sub_sym = scm_caar (s);
SCM old_val = scm_cdar (s);
- drop = false;
if (sub_sym == wanted_sym)
{
*tail = scm_acons (sub_sym, new_val, SCM_EOL);
tail = SCM_CDRLOC(*tail);
- *tail = scm_cdr (s);
- return new_list;
}
else
{
- /* old value should be dropped only if we have another copy of it in the alist */
- copy_count++;
- /*
- Only drop the first instance found.
- the overridden value is always the first
- if this was the only copy, we will return
- the original list anyways so it is not relevant
- if we drop this pair
- */
- if (copy_count == 1)
- drop = true;
+ /* old value is dropped. */
}
- /* we now iterate over every item */
+
+ *tail = scm_cdr (s);
+ return new_list;
}
- /*
- Make a new list with every item
- except for the eventual dropped one
- */
- if (!drop)
- {
- *tail = scm_acons (sub_sym, old_val, SCM_EOL);
- tail = SCM_CDRLOC (*tail);
- }
+
+ *tail = scm_acons (sub_sym, old_val, SCM_EOL);
+ tail = SCM_CDRLOC (*tail);
}
- /*
- If we find more than one copy of the property
- push the new list, else it means we are trying to
- revert the original value
- */
- if (copy_count > 1)
- return new_list;
- else
- return alist;
+ /* Wanted symbol not found: drop newly constructed list. */
+ return alist;
}
me->set_property (scm_car (big_to_small), alist);
}
-