1 files changed, 28 insertions, 0 deletions
diff --git a/032array.cc b/032array.cc
index 1b8d5900..7ad84367 100644
--- a/032array.cc
+++ b/032array.cc
@@ -332,3 +332,31 @@ case LENGTH: {
 recipe_ordinal r = current_instruction().operation;
 if (r == CREATE_ARRAY || r == INDEX || r == INDEX_ADDRESS || r == LENGTH)
   return false;
+
+:(code)
+bool is_mu_array(reagent r) {
+  if (is_literal(r)) return false;
+  while (has_property(r, "lookup")) {
+    if (r.types.empty()) {
+      raise << "can't lookup non-address: " << r.original_string << '\n' << end();
+      return false;
+    }
+    if (r.types.at(0) != Type_ordinal["address"]) {
+      raise << "can't lookup non-address: " << r.original_string << '\n' << end();
+      return false;
+    }
+    r.types.erase(r.types.begin());
+    drop_one_lookup(r);
+  }
+  return !r.types.empty() && r.types.at(0) == Type_ordinal["array"];
+}
+
+void drop_one_lookup(reagent& r) {
+  for (vector<pair<string, vector<string> > >::iterator p = r.properties.begin(); p != r.properties.end(); ++p) {
+    if (p->first == "lookup") {
+      r.properties.erase(p);
+      return;
+    }
+  }
+  assert(false);
+}