Diff to scan the heap

gistfile1.diff

diff --git a/gherkin b/gherkin
index 073e926..06211ba 100755
--- a/gherkin
+++ b/gherkin
@@ -210,6 +210,20 @@ mark() {
   done
 }
 
+test_heap() {
+  local top
+  top=$((cons_ptr + 1))
+  while [[ -z "${marks[${tag_marker}002${top}]}" ]] && ((top < cons_limit)); do
+    ((top++))
+  done
+  if ((top < cons_limit)) ; then
+    echo "ERROR: Corrupted heap"
+    echo "Error at top + $((top - cons_ptr))"
+  else
+    echo "Clean heap"
+  fi
+}
+
 gc() {
   echo "GC..." >&2
   IFS="$DEFAULT_IFS"
@@ -220,6 +234,7 @@ gc() {
   while [[ -n "${marks[${tag_marker}002${cons_ptr}]}" ]]; do
     unset marks["${tag_marker}002$((cons_ptr++))"]
   done
+  test_heap
   if [[ $cons_ptr == $cons_limit ]]; then
     echo "expanding heap..." >&2
     cons_limit=$((cons_limit + heap_increment))