--- a/liboctave/util/lo-array-gripes.h	Fri Oct 02 12:25:39 2015 -0400
+++ b/liboctave/util/lo-array-gripes.h	Fri Oct 02 15:07:37 2015 -0400
@@ -24,6 +24,80 @@
 #define octave_lo_array_gripes_h 1
 
 #include "dim-vector.h"
+#include "quit.h"
+
+// Exception thrown by gripe_invalid_index
+// This is thrown when the invalid index is detected, at which point nd and dim
+// are usually not known.  It is caught at the place they are known, where a
+// new  gripe_invalid_index  is called.
+//
+// Typically, this should be caught after any call to
+// octave_value_list::index_vector()
+class index_exception : public octave_execution_exception
+{
+public:
+
+  index_exception (const char *index_in, octave_idx_type nd_in = 0,
+                   octave_idx_type dim_in = 0, const char *var_in = "")
+    : index (index_in), nd (nd_in), dim (dim_in), var (var_in)
+  { }
+
+  ~index_exception (void) throw () { }
+
+  // Erroneous index value.  Called in what, and by external code
+  // (e.g., nth_element) to make a custom error message.
+  const char *idx (void) const { return index.c_str (); }
+
+  // details set by subclass.
+  virtual const char* explain (void) const = 0;
+
+  // ID of error to throw.
+  virtual const char* id (void) const = 0;
+
+  virtual const char* err (void) throw ();
+
+  // Position of error: dimension in error, and number of dimensions.
+  void set_pos (octave_idx_type nd_in, octave_idx_type dim_in)
+  {
+    nd = nd_in;
+    dim = dim_in;
+  }
+
+  void set_pos_if_unset (octave_idx_type nd_in, octave_idx_type dim_in)
+  {
+    if (nd == 0)
+      {
+        nd  = nd_in;
+        dim = dim_in;
+      }
+  }
+
+  // Name of variable being indexed.  eye(2)(1,1) gives "<unknown>".
+  void set_var (std::string var_in) { var = var_in; }
+
+private:
+
+  // Value of invalid index.
+  std::string index;
+
+  // Formatted message returned by what(), (not on stack).
+  std::string msg;      
+
+protected:
+
+  // Show what's wrong, e.g.,  A(-1,_), A(0+1i).
+  std::string access (void) const;
+
+  // Number of dimensions of indexed object.
+  octave_idx_type nd;
+
+  // Dimension number in which invalid index occurred.
+  octave_idx_type dim;
+
+  // Name of variable being indexed.
+  std::string var;
+
+};
 
 extern OCTAVE_API const char *error_id_nonconformant_args;
 
@@ -57,6 +131,11 @@
 
 extern void OCTAVE_API
 gripe_index_out_of_range (int nd, int dim,
+                          octave_idx_type iext, octave_idx_type ext,
+                          const dim_vector& d);
+
+extern void OCTAVE_API
+gripe_index_out_of_range (int nd, int dim,
                           octave_idx_type iext, octave_idx_type ext);
 
 extern void OCTAVE_API
@@ -64,18 +143,21 @@
                               octave_idx_type ext);
 
 extern void OCTAVE_API
-gripe_invalid_index (void);
+gripe_invalid_index (double, octave_idx_type nd=0,
+                     octave_idx_type dim=0, const char *var = NULL);
+
+extern void OCTAVE_API
+gripe_invalid_index (octave_idx_type n, octave_idx_type nd=0,
+                     octave_idx_type dim=0, const char *var = NULL);
+
+extern void OCTAVE_API
+gripe_invalid_index (const char *idx, octave_idx_type nd=0,
+                     octave_idx_type dim=0, const char *var = NULL);
 
 extern void OCTAVE_API
 gripe_invalid_resize (void);
 
 extern void OCTAVE_API
-gripe_invalid_assignment_size (void);
-
-extern void OCTAVE_API
-gripe_assignment_dimension_mismatch (void);
-
-extern void OCTAVE_API
 gripe_singular_matrix (double rcond = 0.0);
 
 #endif