--- a/src/ops.h
+++ b/src/ops.h
@@ -40,6 +40,10 @@
     (octave_value::op, t1::static_type_id (), t2::static_type_id (), \
      oct_binop_ ## f);
 
+#define INSTALL_CATOP(t1, t2, f) \
+  octave_value_typeinfo::register_cat_op \
+    (t1::static_type_id (), t2::static_type_id (), oct_catop_ ## f);
+
 #define INSTALL_ASSIGNOP(op, t1, t2, f) \
   octave_value_typeinfo::register_assign_op \
     (octave_value::op, t1::static_type_id (), t2::static_type_id (), \
@@ -306,6 +310,39 @@
 		       a2.rows (), a2.columns ()); \
   return octave_value ()
 
+#define CATOPDECL(name, a1, a2)	\
+  static octave_value \
+  oct_catop_ ## name (const octave_value& a1, const octave_value& a2, \
+		      const Array<int>& ra_idx)
+
+#define DEFCATOPX(name, t1, t2)	\
+  CATOPDECL (name, , )
+
+#define DEFCATOP(name, t1, t2)	\
+  CATOPDECL (name, a1, a2)
+
+// XXX FIXME XXX -- in some cases, the constructor isn't necessary.
+
+#define DEFCATOP_FN(name, t1, t2, f) \
+  CATOPDECL (name, a1, a2)	     \
+  { \
+    CAST_BINOP_ARGS (const octave_ ## t1&, const octave_ ## t2&); \
+    return octave_value (f (v1.t1 ## _value (), v2.t2 ## _value (), ra_idx));	\
+  }
+
+#define DEFNDCATOP_FN(name, t1, t2, e1, e2, f)	\
+  CATOPDECL (name, a1, a2)			\
+  { \
+    CAST_BINOP_ARGS (const octave_ ## t1&, const octave_ ## t2&); \
+    return octave_value (f (v1.e1 ## _value (), v2.e2 ## _value (), ra_idx));	\
+  }
+
+#define CATOP_NONCONFORMANT(msg) \
+  gripe_nonconformant (msg, \
+		       a1.rows (), a1.columns (), \
+		       a2.rows (), a2.columns ()); \
+  return octave_value ()
+
 #endif
 
 /*