--- a/liboctave/array/idx-vector.h	Thu Dec 01 14:23:45 2022 -0800
+++ b/liboctave/array/idx-vector.h	Thu Dec 01 18:02:15 2022 -0800
@@ -44,992 +44,992 @@
 
 OCTAVE_BEGIN_NAMESPACE(octave)
 
-  // Design rationale:
-  //
-  // idx_vector is a reference-counting, polymorphic pointer, that can
-  // contain 4 types of index objects: a magic colon, a range, a scalar,
-  // or an index vector.
-  //
-  // Polymorphic methods for single element access are provided, as well
-  // as templates implementing "early dispatch", i.e., hoisting the checks
-  // for index type out of loops.
+// Design rationale:
+//
+// idx_vector is a reference-counting, polymorphic pointer, that can
+// contain 4 types of index objects: a magic colon, a range, a scalar,
+// or an index vector.
+//
+// Polymorphic methods for single element access are provided, as well
+// as templates implementing "early dispatch", i.e., hoisting the checks
+// for index type out of loops.
+
+class
+OCTAVE_API
+idx_vector
+{
+public:
+
+  enum idx_class_type
+  {
+    class_invalid = -1,
+    class_colon = 0,
+    class_range,
+    class_scalar,
+    class_vector,
+    class_mask
+  };
+
+  template <typename T, typename D> friend class std::unique_ptr;
+
+private:
+
+  class OCTAVE_API idx_base_rep
+  {
+  public:
+
+    idx_base_rep (void) : m_count (1) { }
+
+    // No copying!
+
+    idx_base_rep (const idx_base_rep&) = delete;
 
-  class
-  OCTAVE_API
-  idx_vector
+    idx_base_rep& operator = (const idx_base_rep&) = delete;
+
+    virtual ~idx_base_rep (void) = default;
+
+    // Non-range-checking element query.
+    virtual octave_idx_type xelem (octave_idx_type i) const = 0;
+
+    // Range-checking element query.
+    virtual octave_idx_type checkelem (octave_idx_type i) const = 0;
+
+    // Length of the index vector.
+    virtual octave_idx_type length (octave_idx_type n) const = 0;
+
+    // The maximum index + 1.  The actual dimension is passed in.
+    virtual octave_idx_type extent (octave_idx_type n) const = 0;
+
+    // Index class.
+    virtual idx_class_type idx_class (void) const { return class_invalid; }
+
+    // Sorts, maybe uniqifies, and returns a clone object pointer.
+    virtual idx_base_rep * sort_uniq_clone (bool uniq = false) = 0;
+    // Sorts, and returns a sorting permutation (aka Array::sort).
+    virtual idx_base_rep * sort_idx (Array<octave_idx_type>&) = 0;
+
+    // Checks whether the index is colon or a range equivalent to colon.
+    virtual bool is_colon_equiv (octave_idx_type) const { return false; }
+
+    // The original dimensions of object (used when subscribing by matrices).
+    virtual dim_vector orig_dimensions (void) const { return dim_vector (); }
+
+    // i/o
+    virtual std::ostream& print (std::ostream& os) const = 0;
+
+    virtual Array<octave_idx_type> as_array (void);
+
+    refcount<octave_idx_type> m_count;
+  };
+
+  // The magic colon index.
+  class OCTAVE_API idx_colon_rep : public idx_base_rep
   {
   public:
 
-    enum idx_class_type
+    idx_colon_rep (void) = default;
+
+    OCTAVE_API idx_colon_rep (char c);
+
+    // No copying!
+
+    idx_colon_rep (const idx_colon_rep& idx) = delete;
+
+    idx_colon_rep& operator = (const idx_colon_rep& idx) = delete;
+
+    octave_idx_type xelem (octave_idx_type i) const { return i; }
+
+    OCTAVE_API octave_idx_type checkelem (octave_idx_type i) const;
+
+    octave_idx_type length (octave_idx_type n) const { return n; }
+
+    octave_idx_type extent (octave_idx_type n) const { return n; }
+
+    idx_class_type idx_class (void) const { return class_colon; }
+
+    idx_base_rep * sort_uniq_clone (bool = false)
+    { m_count++; return this; }
+
+    OCTAVE_NORETURN idx_base_rep * sort_idx (Array<octave_idx_type>&);
+
+    bool is_colon_equiv (octave_idx_type) const { return true; }
+
+    OCTAVE_API std::ostream& print (std::ostream& os) const;
+  };
+
+  // To distinguish the "direct" constructors that blindly trust the data.
+  enum direct { DIRECT };
+
+  // The integer range index.
+  class OCTAVE_API idx_range_rep : public idx_base_rep
+  {
+  public:
+
+    idx_range_rep (void) = delete;
+
+    idx_range_rep (octave_idx_type start, octave_idx_type len,
+                   octave_idx_type step, direct)
+      : idx_base_rep (), m_start (start), m_len (len), m_step (step) { }
+
+    // Zero-based constructor for index range starting at `start` (inclusive)
+    // and ending at `limit` (exclusive) in steps of `step`.
+    idx_range_rep (octave_idx_type start, octave_idx_type limit,
+                   octave_idx_type step);
+
+    OCTAVE_API idx_range_rep (const range<double>&);
+
+    // No copying!
+
+    idx_range_rep (const idx_range_rep& idx) = delete;
+
+    idx_range_rep& operator = (const idx_range_rep& idx) = delete;
+
+    octave_idx_type xelem (octave_idx_type i) const
+    { return m_start + i * m_step; }
+
+    octave_idx_type checkelem (octave_idx_type i) const;
+
+    octave_idx_type length (octave_idx_type) const { return m_len; }
+
+    octave_idx_type extent (octave_idx_type n) const
     {
-      class_invalid = -1,
-      class_colon = 0,
-      class_range,
-      class_scalar,
-      class_vector,
-      class_mask
-    };
+      return m_len ? std::max (n, m_start + 1 + (m_step < 0 ? 0 : m_step * (m_len - 1))) : n;
+    }
+
+    idx_class_type idx_class (void) const { return class_range; }
+
+    OCTAVE_API idx_base_rep * sort_uniq_clone (bool uniq = false);
+
+    OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
+
+    bool is_colon_equiv (octave_idx_type n) const
+    { return m_start == 0 && m_step == 1 && m_len == n; }
 
-    template <typename T, typename D> friend class std::unique_ptr;
+    dim_vector orig_dimensions (void) const
+    { return dim_vector (1, m_len); }
+
+    octave_idx_type get_start (void) const { return m_start; }
+
+    octave_idx_type get_step (void) const { return m_step; }
+
+    OCTAVE_API std::ostream& print (std::ostream& os) const;
+
+    OCTAVE_API range<double> unconvert (void) const;
+
+    OCTAVE_API Array<octave_idx_type> as_array (void);
 
   private:
 
-    class OCTAVE_API idx_base_rep
-    {
-    public:
-
-      idx_base_rep (void) : m_count (1) { }
-
-      // No copying!
-
-      idx_base_rep (const idx_base_rep&) = delete;
-
-      idx_base_rep& operator = (const idx_base_rep&) = delete;
-
-      virtual ~idx_base_rep (void) = default;
-
-      // Non-range-checking element query.
-      virtual octave_idx_type xelem (octave_idx_type i) const = 0;
-
-      // Range-checking element query.
-      virtual octave_idx_type checkelem (octave_idx_type i) const = 0;
-
-      // Length of the index vector.
-      virtual octave_idx_type length (octave_idx_type n) const = 0;
-
-      // The maximum index + 1.  The actual dimension is passed in.
-      virtual octave_idx_type extent (octave_idx_type n) const = 0;
-
-      // Index class.
-      virtual idx_class_type idx_class (void) const { return class_invalid; }
-
-      // Sorts, maybe uniqifies, and returns a clone object pointer.
-      virtual idx_base_rep * sort_uniq_clone (bool uniq = false) = 0;
-      // Sorts, and returns a sorting permutation (aka Array::sort).
-      virtual idx_base_rep * sort_idx (Array<octave_idx_type>&) = 0;
-
-      // Checks whether the index is colon or a range equivalent to colon.
-      virtual bool is_colon_equiv (octave_idx_type) const { return false; }
-
-      // The original dimensions of object (used when subscribing by matrices).
-      virtual dim_vector orig_dimensions (void) const { return dim_vector (); }
-
-      // i/o
-      virtual std::ostream& print (std::ostream& os) const = 0;
-
-      virtual Array<octave_idx_type> as_array (void);
+    octave_idx_type m_start, m_len, m_step;
+  };
 
-      refcount<octave_idx_type> m_count;
-    };
-
-    // The magic colon index.
-    class OCTAVE_API idx_colon_rep : public idx_base_rep
-    {
-    public:
-
-      idx_colon_rep (void) = default;
-
-      OCTAVE_API idx_colon_rep (char c);
-
-      // No copying!
-
-      idx_colon_rep (const idx_colon_rep& idx) = delete;
-
-      idx_colon_rep& operator = (const idx_colon_rep& idx) = delete;
-
-      octave_idx_type xelem (octave_idx_type i) const { return i; }
-
-      OCTAVE_API octave_idx_type checkelem (octave_idx_type i) const;
+  // The integer scalar index.
+  class OCTAVE_API idx_scalar_rep : public idx_base_rep
+  {
+  public:
 
-      octave_idx_type length (octave_idx_type n) const { return n; }
-
-      octave_idx_type extent (octave_idx_type n) const { return n; }
-
-      idx_class_type idx_class (void) const { return class_colon; }
-
-      idx_base_rep * sort_uniq_clone (bool = false)
-      { m_count++; return this; }
-
-      OCTAVE_NORETURN idx_base_rep * sort_idx (Array<octave_idx_type>&);
+    idx_scalar_rep (void) = delete;
 
-      bool is_colon_equiv (octave_idx_type) const { return true; }
-
-      OCTAVE_API std::ostream& print (std::ostream& os) const;
-    };
+    idx_scalar_rep (octave_idx_type i, direct) : idx_base_rep (), m_data (i) { }
 
-    // To distinguish the "direct" constructors that blindly trust the data.
-    enum direct { DIRECT };
-
-    // The integer range index.
-    class OCTAVE_API idx_range_rep : public idx_base_rep
-    {
-    public:
+    // No copying!
 
-      idx_range_rep (void) = delete;
-
-      idx_range_rep (octave_idx_type start, octave_idx_type len,
-                     octave_idx_type step, direct)
-        : idx_base_rep (), m_start (start), m_len (len), m_step (step) { }
-
-      // Zero-based constructor for index range starting at `start` (inclusive)
-      // and ending at `limit` (exclusive) in steps of `step`.
-      idx_range_rep (octave_idx_type start, octave_idx_type limit,
-                     octave_idx_type step);
-
-      OCTAVE_API idx_range_rep (const range<double>&);
-
-      // No copying!
-
-      idx_range_rep (const idx_range_rep& idx) = delete;
-
-      idx_range_rep& operator = (const idx_range_rep& idx) = delete;
-
-      octave_idx_type xelem (octave_idx_type i) const
-      { return m_start + i * m_step; }
+    idx_scalar_rep (const idx_scalar_rep& idx) = delete;
 
-      octave_idx_type checkelem (octave_idx_type i) const;
-
-      octave_idx_type length (octave_idx_type) const { return m_len; }
-
-      octave_idx_type extent (octave_idx_type n) const
-      {
-        return m_len ? std::max (n, m_start + 1 + (m_step < 0 ? 0 : m_step * (m_len - 1))) : n;
-      }
-
-      idx_class_type idx_class (void) const { return class_range; }
+    idx_scalar_rep& operator = (const idx_scalar_rep& idx) = delete;
 
-      OCTAVE_API idx_base_rep * sort_uniq_clone (bool uniq = false);
-
-      OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
-
-      bool is_colon_equiv (octave_idx_type n) const
-      { return m_start == 0 && m_step == 1 && m_len == n; }
-
-      dim_vector orig_dimensions (void) const
-      { return dim_vector (1, m_len); }
-
-      octave_idx_type get_start (void) const { return m_start; }
+    // Zero-based constructor.
+    OCTAVE_API idx_scalar_rep (octave_idx_type i);
 
-      octave_idx_type get_step (void) const { return m_step; }
-
-      OCTAVE_API std::ostream& print (std::ostream& os) const;
-
-      OCTAVE_API range<double> unconvert (void) const;
-
-      OCTAVE_API Array<octave_idx_type> as_array (void);
-
-    private:
-
-      octave_idx_type m_start, m_len, m_step;
-    };
-
-    // The integer scalar index.
-    class OCTAVE_API idx_scalar_rep : public idx_base_rep
-    {
-    public:
-
-      idx_scalar_rep (void) = delete;
-
-      idx_scalar_rep (octave_idx_type i, direct) : idx_base_rep (), m_data (i) { }
-
-      // No copying!
+    template <typename T>
+    idx_scalar_rep (T x);
 
-      idx_scalar_rep (const idx_scalar_rep& idx) = delete;
-
-      idx_scalar_rep& operator = (const idx_scalar_rep& idx) = delete;
-
-      // Zero-based constructor.
-      OCTAVE_API idx_scalar_rep (octave_idx_type i);
-
-      template <typename T>
-        idx_scalar_rep (T x);
-
-      octave_idx_type xelem (octave_idx_type) const { return m_data; }
+    octave_idx_type xelem (octave_idx_type) const { return m_data; }
 
-      OCTAVE_API octave_idx_type checkelem (octave_idx_type i) const;
-
-      octave_idx_type length (octave_idx_type) const { return 1; }
+    OCTAVE_API octave_idx_type checkelem (octave_idx_type i) const;
 
-      octave_idx_type extent (octave_idx_type n) const
-      { return std::max (n, m_data + 1); }
-
-      idx_class_type idx_class (void) const { return class_scalar; }
-
-      idx_base_rep * sort_uniq_clone (bool = false)
-      { m_count++; return this; }
+    octave_idx_type length (octave_idx_type) const { return 1; }
 
-      OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
-
-      bool is_colon_equiv (octave_idx_type n) const
-      { return n == 1 && m_data == 0; }
-
-      dim_vector orig_dimensions (void) const { return dim_vector (1, 1); }
-
-      octave_idx_type get_data (void) const { return m_data; }
-
-      OCTAVE_API std::ostream& print (std::ostream& os) const;
-
-      OCTAVE_API double unconvert (void) const;
-
-      OCTAVE_API Array<octave_idx_type> as_array (void);
-
-    private:
-
-      octave_idx_type m_data;
-    };
+    octave_idx_type extent (octave_idx_type n) const
+    { return std::max (n, m_data + 1); }
 
-    // The integer vector index.
-    class OCTAVE_API idx_vector_rep : public idx_base_rep
-    {
-    public:
-
-      idx_vector_rep (void)
-        : m_data (nullptr), m_len (0), m_ext (0), m_aowner (nullptr), m_orig_dims () { }
-
-      // Direct constructor.
-      idx_vector_rep (octave_idx_type *data, octave_idx_type len,
-                      octave_idx_type ext, const dim_vector& od, direct)
-        : idx_base_rep (), m_data (data), m_len (len), m_ext (ext),
-          m_aowner (nullptr), m_orig_dims (od)
-      { }
-
-      // Zero-based constructor.
-      OCTAVE_API idx_vector_rep (const Array<octave_idx_type>& inda);
-
-      OCTAVE_API idx_vector_rep (const Array<octave_idx_type>& inda,
-                                 octave_idx_type ext, direct);
-
-      template <typename T>
-        idx_vector_rep (const Array<T>&);
+    idx_class_type idx_class (void) const { return class_scalar; }
 
-      OCTAVE_API idx_vector_rep (bool);
-
-      OCTAVE_API idx_vector_rep (const Array<bool>&, octave_idx_type = -1);
-
-      OCTAVE_API idx_vector_rep (const Sparse<bool>&);
-
-      // No copying!
-
-      idx_vector_rep (const idx_vector_rep& idx) = delete;
+    idx_base_rep * sort_uniq_clone (bool = false)
+    { m_count++; return this; }
 
-      idx_vector_rep& operator = (const idx_vector_rep& idx) = delete;
-
-      ~idx_vector_rep (void);
-
-      octave_idx_type xelem (octave_idx_type i) const { return m_data[i]; }
-
-      OCTAVE_API octave_idx_type checkelem (octave_idx_type i) const;
-
-      octave_idx_type length (octave_idx_type) const { return m_len; }
+    OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
 
-      octave_idx_type extent (octave_idx_type n) const
-      { return std::max (n, m_ext); }
-
-      idx_class_type idx_class (void) const { return class_vector; }
-
-      idx_base_rep * sort_uniq_clone (bool uniq = false);
-
-      OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
-
-      dim_vector orig_dimensions (void) const { return m_orig_dims; }
+    bool is_colon_equiv (octave_idx_type n) const
+    { return n == 1 && m_data == 0; }
 
-      const octave_idx_type * get_data (void) const { return m_data; }
-
-      OCTAVE_API std::ostream& print (std::ostream& os) const;
-
-      OCTAVE_API Array<double> unconvert (void) const;
-
-      OCTAVE_API Array<octave_idx_type> as_array (void);
-
-    private:
-
-      const octave_idx_type *m_data;
-      octave_idx_type m_len;
-      octave_idx_type m_ext;
+    dim_vector orig_dimensions (void) const { return dim_vector (1, 1); }
 
-      // This is a trick to allow user-given zero-based arrays to be used
-      // as indices without copying.  If the following pointer is nonzero,
-      // we do not own the data, but rather have an Array<octave_idx_type>
-      // object that provides us the data.  Note that we need a pointer
-      // because we deferred the Array<T> declaration and we do not want
-      // it yet to be defined.
-
-      Array<octave_idx_type> *m_aowner;
+    octave_idx_type get_data (void) const { return m_data; }
 
-      dim_vector m_orig_dims;
-    };
-
-    // The logical mask index.
-    class OCTAVE_API idx_mask_rep : public idx_base_rep
-    {
-    public:
-
-      idx_mask_rep (void) = delete;
+    OCTAVE_API std::ostream& print (std::ostream& os) const;
 
-      // Direct constructor.
-      idx_mask_rep (bool *data, octave_idx_type len,
-                    octave_idx_type ext, const dim_vector& od, direct)
-        : idx_base_rep (), m_data (data), m_len (len), m_ext (ext),
-          m_lsti (-1), m_lste (-1), m_aowner (nullptr), m_orig_dims (od)
-      { }
-
-      OCTAVE_API idx_mask_rep (bool);
-
-      OCTAVE_API idx_mask_rep (const Array<bool>&, octave_idx_type = -1);
-
-      // No copying!
+    OCTAVE_API double unconvert (void) const;
 
-      idx_mask_rep (const idx_mask_rep& idx) = delete;
-
-      idx_mask_rep& operator = (const idx_mask_rep& idx) = delete;
-
-      OCTAVE_API ~idx_mask_rep (void);
-
-      octave_idx_type xelem (octave_idx_type i) const;
-
-      octave_idx_type checkelem (octave_idx_type i) const;
-
-      octave_idx_type length (octave_idx_type) const { return m_len; }
-
-      octave_idx_type extent (octave_idx_type n) const
-      { return std::max (n, m_ext); }
+    OCTAVE_API Array<octave_idx_type> as_array (void);
 
-      idx_class_type idx_class (void) const { return class_mask; }
-
-      idx_base_rep * sort_uniq_clone (bool = false)
-      { m_count++; return this; }
-
-      OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
-
-      dim_vector orig_dimensions (void) const { return m_orig_dims; }
-
-      bool is_colon_equiv (octave_idx_type n) const
-      { return m_len == n && m_ext == n; }
-
-      const bool * get_data (void) const { return m_data; }
-
-      OCTAVE_API std::ostream& print (std::ostream& os) const;
-
-      OCTAVE_API Array<bool> unconvert (void) const;
-
-      OCTAVE_API Array<octave_idx_type> as_array (void);
-
-    private:
+  private:
 
-      const bool *m_data;
-      octave_idx_type m_len;
-      octave_idx_type m_ext;
-
-      // FIXME: I'm not sure if this is a good design.  Maybe it would be
-      // better to employ some sort of generalized iteration scheme.
-      mutable octave_idx_type m_lsti;
-      mutable octave_idx_type m_lste;
+    octave_idx_type m_data;
+  };
 
-      // This is a trick to allow user-given mask arrays to be used as
-      // indices without copying.  If the following pointer is nonzero, we
-      // do not own the data, but rather have an Array<bool> object that
-      // provides us the data.  Note that we need a pointer because we
-      // deferred the Array<T> declaration and we do not want it yet to be
-      // defined.
-
-      Array<bool> *m_aowner;
-
-      dim_vector m_orig_dims;
-    };
-
-    idx_vector (idx_base_rep *r) : m_rep (r) { }
-
-    // The shared empty vector representation (for fast default
-    // constructor).
-    static OCTAVE_API idx_vector_rep * nil_rep (void);
-
+  // The integer vector index.
+  class OCTAVE_API idx_vector_rep : public idx_base_rep
+  {
   public:
 
-    // Fast empty constructor.
-    idx_vector (void) : m_rep (nil_rep ()) { m_rep->m_count++; }
+    idx_vector_rep (void)
+      : m_data (nullptr), m_len (0), m_ext (0), m_aowner (nullptr), m_orig_dims () { }
+
+    // Direct constructor.
+    idx_vector_rep (octave_idx_type *data, octave_idx_type len,
+                    octave_idx_type ext, const dim_vector& od, direct)
+      : idx_base_rep (), m_data (data), m_len (len), m_ext (ext),
+        m_aowner (nullptr), m_orig_dims (od)
+    { }
+
+    // Zero-based constructor.
+    OCTAVE_API idx_vector_rep (const Array<octave_idx_type>& inda);
+
+    OCTAVE_API idx_vector_rep (const Array<octave_idx_type>& inda,
+                               octave_idx_type ext, direct);
+
+    template <typename T>
+    idx_vector_rep (const Array<T>&);
+
+    OCTAVE_API idx_vector_rep (bool);
+
+    OCTAVE_API idx_vector_rep (const Array<bool>&, octave_idx_type = -1);
+
+    OCTAVE_API idx_vector_rep (const Sparse<bool>&);
+
+    // No copying!
+
+    idx_vector_rep (const idx_vector_rep& idx) = delete;
+
+    idx_vector_rep& operator = (const idx_vector_rep& idx) = delete;
+
+    ~idx_vector_rep (void);
+
+    octave_idx_type xelem (octave_idx_type i) const { return m_data[i]; }
+
+    OCTAVE_API octave_idx_type checkelem (octave_idx_type i) const;
+
+    octave_idx_type length (octave_idx_type) const { return m_len; }
+
+    octave_idx_type extent (octave_idx_type n) const
+    { return std::max (n, m_ext); }
+
+    idx_class_type idx_class (void) const { return class_vector; }
+
+    idx_base_rep * sort_uniq_clone (bool uniq = false);
+
+    OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
+
+    dim_vector orig_dimensions (void) const { return m_orig_dims; }
+
+    const octave_idx_type * get_data (void) const { return m_data; }
+
+    OCTAVE_API std::ostream& print (std::ostream& os) const;
+
+    OCTAVE_API Array<double> unconvert (void) const;
+
+    OCTAVE_API Array<octave_idx_type> as_array (void);
+
+  private:
+
+    const octave_idx_type *m_data;
+    octave_idx_type m_len;
+    octave_idx_type m_ext;
+
+    // This is a trick to allow user-given zero-based arrays to be used
+    // as indices without copying.  If the following pointer is nonzero,
+    // we do not own the data, but rather have an Array<octave_idx_type>
+    // object that provides us the data.  Note that we need a pointer
+    // because we deferred the Array<T> declaration and we do not want
+    // it yet to be defined.
+
+    Array<octave_idx_type> *m_aowner;
+
+    dim_vector m_orig_dims;
+  };
+
+  // The logical mask index.
+  class OCTAVE_API idx_mask_rep : public idx_base_rep
+  {
+  public:
+
+    idx_mask_rep (void) = delete;
 
-    // Zero-based constructors (for use from C++).
-    idx_vector (octave_idx_type i) : m_rep (new idx_scalar_rep (i)) { }
+    // Direct constructor.
+    idx_mask_rep (bool *data, octave_idx_type len,
+                  octave_idx_type ext, const dim_vector& od, direct)
+      : idx_base_rep (), m_data (data), m_len (len), m_ext (ext),
+        m_lsti (-1), m_lste (-1), m_aowner (nullptr), m_orig_dims (od)
+    { }
+
+    OCTAVE_API idx_mask_rep (bool);
+
+    OCTAVE_API idx_mask_rep (const Array<bool>&, octave_idx_type = -1);
+
+    // No copying!
+
+    idx_mask_rep (const idx_mask_rep& idx) = delete;
+
+    idx_mask_rep& operator = (const idx_mask_rep& idx) = delete;
+
+    OCTAVE_API ~idx_mask_rep (void);
+
+    octave_idx_type xelem (octave_idx_type i) const;
+
+    octave_idx_type checkelem (octave_idx_type i) const;
+
+    octave_idx_type length (octave_idx_type) const { return m_len; }
+
+    octave_idx_type extent (octave_idx_type n) const
+    { return std::max (n, m_ext); }
+
+    idx_class_type idx_class (void) const { return class_mask; }
+
+    idx_base_rep * sort_uniq_clone (bool = false)
+    { m_count++; return this; }
+
+    OCTAVE_API idx_base_rep * sort_idx (Array<octave_idx_type>&);
+
+    dim_vector orig_dimensions (void) const { return m_orig_dims; }
+
+    bool is_colon_equiv (octave_idx_type n) const
+    { return m_len == n && m_ext == n; }
+
+    const bool * get_data (void) const { return m_data; }
+
+    OCTAVE_API std::ostream& print (std::ostream& os) const;
+
+    OCTAVE_API Array<bool> unconvert (void) const;
+
+    OCTAVE_API Array<octave_idx_type> as_array (void);
+
+  private:
+
+    const bool *m_data;
+    octave_idx_type m_len;
+    octave_idx_type m_ext;
+
+    // FIXME: I'm not sure if this is a good design.  Maybe it would be
+    // better to employ some sort of generalized iteration scheme.
+    mutable octave_idx_type m_lsti;
+    mutable octave_idx_type m_lste;
+
+    // This is a trick to allow user-given mask arrays to be used as
+    // indices without copying.  If the following pointer is nonzero, we
+    // do not own the data, but rather have an Array<bool> object that
+    // provides us the data.  Note that we need a pointer because we
+    // deferred the Array<T> declaration and we do not want it yet to be
+    // defined.
+
+    Array<bool> *m_aowner;
+
+    dim_vector m_orig_dims;
+  };
+
+  idx_vector (idx_base_rep *r) : m_rep (r) { }
+
+  // The shared empty vector representation (for fast default
+  // constructor).
+  static OCTAVE_API idx_vector_rep * nil_rep (void);
+
+public:
+
+  // Fast empty constructor.
+  idx_vector (void) : m_rep (nil_rep ()) { m_rep->m_count++; }
+
+  // Zero-based constructors (for use from C++).
+  idx_vector (octave_idx_type i) : m_rep (new idx_scalar_rep (i)) { }
 
 #if OCTAVE_SIZEOF_INT != OCTAVE_SIZEOF_IDX_TYPE
-    idx_vector (int i)
-      : m_rep (new idx_scalar_rep (static_cast<octave_idx_type> (i))) { }
+  idx_vector (int i)
+    : m_rep (new idx_scalar_rep (static_cast<octave_idx_type> (i))) { }
 #endif
 
 #if (OCTAVE_SIZEOF_F77_INT_TYPE != OCTAVE_SIZEOF_IDX_TYPE \
      && OCTAVE_SIZEOF_F77_INT_TYPE != OCTAVE_SIZEOF_INT)
-    idx_vector (octave_f77_int_type i)
-      : m_rep (new idx_scalar_rep (static_cast<octave_idx_type> (i))) { }
+  idx_vector (octave_f77_int_type i)
+    : m_rep (new idx_scalar_rep (static_cast<octave_idx_type> (i))) { }
 #endif
 
-    idx_vector (octave_idx_type start, octave_idx_type limit,
-                octave_idx_type step = 1)
-      : m_rep (new idx_range_rep (start, limit, step)) { }
+  idx_vector (octave_idx_type start, octave_idx_type limit,
+              octave_idx_type step = 1)
+    : m_rep (new idx_range_rep (start, limit, step)) { }
 
-    static idx_vector
-    make_range (octave_idx_type start, octave_idx_type step,
-                octave_idx_type len)
-    {
-      return idx_vector (new idx_range_rep (start, len, step, DIRECT));
-    }
+  static idx_vector
+  make_range (octave_idx_type start, octave_idx_type step,
+              octave_idx_type len)
+  {
+    return idx_vector (new idx_range_rep (start, len, step, DIRECT));
+  }
 
-    idx_vector (const Array<octave_idx_type>& inda)
-      : m_rep (new idx_vector_rep (inda)) { }
+  idx_vector (const Array<octave_idx_type>& inda)
+    : m_rep (new idx_vector_rep (inda)) { }
 
-    // Directly pass extent, no checking.
-    idx_vector (const Array<octave_idx_type>& inda, octave_idx_type ext)
-      : m_rep (new idx_vector_rep (inda, ext, DIRECT)) { }
+  // Directly pass extent, no checking.
+  idx_vector (const Array<octave_idx_type>& inda, octave_idx_type ext)
+    : m_rep (new idx_vector_rep (inda, ext, DIRECT)) { }
 
-    // Colon is best constructed by simply copying (or referencing) this member.
-    static const idx_vector colon;
+  // Colon is best constructed by simply copying (or referencing) this member.
+  static const idx_vector colon;
 
-    // or passing ':' here
-    idx_vector (char c) : m_rep (new idx_colon_rep (c)) { }
+  // or passing ':' here
+  idx_vector (char c) : m_rep (new idx_colon_rep (c)) { }
 
-    // Conversion constructors (used by interpreter).
+  // Conversion constructors (used by interpreter).
 
-    template <typename T>
-    idx_vector (octave_int<T> x) : m_rep (new idx_scalar_rep (x)) { }
+  template <typename T>
+  idx_vector (octave_int<T> x) : m_rep (new idx_scalar_rep (x)) { }
 
-    idx_vector (double x) : m_rep (new idx_scalar_rep (x)) { }
+  idx_vector (double x) : m_rep (new idx_scalar_rep (x)) { }
 
-    idx_vector (float x) : m_rep (new idx_scalar_rep (x)) { }
+  idx_vector (float x) : m_rep (new idx_scalar_rep (x)) { }
 
-    // A scalar bool does not necessarily map to scalar index.
-    idx_vector (bool x) : m_rep (new idx_mask_rep (x)) { }
+  // A scalar bool does not necessarily map to scalar index.
+  idx_vector (bool x) : m_rep (new idx_mask_rep (x)) { }
 
-    template <typename T>
-    idx_vector (const Array<octave_int<T>>& nda)
-      : m_rep (new idx_vector_rep (nda)) { }
+  template <typename T>
+  idx_vector (const Array<octave_int<T>>& nda)
+    : m_rep (new idx_vector_rep (nda)) { }
 
-    idx_vector (const Array<double>& nda) : m_rep (new idx_vector_rep (nda)) { }
+  idx_vector (const Array<double>& nda) : m_rep (new idx_vector_rep (nda)) { }
 
-    idx_vector (const Array<float>& nda) : m_rep (new idx_vector_rep (nda)) { }
+  idx_vector (const Array<float>& nda) : m_rep (new idx_vector_rep (nda)) { }
 
-    OCTAVE_API idx_vector (const Array<bool>& nda);
+  OCTAVE_API idx_vector (const Array<bool>& nda);
 
-    idx_vector (const range<double>& r) : m_rep (new idx_range_rep (r)) { }
+  idx_vector (const range<double>& r) : m_rep (new idx_range_rep (r)) { }
 
-    idx_vector (const Sparse<bool>& nda) : m_rep (new idx_vector_rep (nda)) { }
+  idx_vector (const Sparse<bool>& nda) : m_rep (new idx_vector_rep (nda)) { }
 
-    idx_vector (const idx_vector& a) : m_rep (a.m_rep) { m_rep->m_count++; }
+  idx_vector (const idx_vector& a) : m_rep (a.m_rep) { m_rep->m_count++; }
 
-    ~idx_vector (void)
-    {
-      if (--m_rep->m_count == 0 && m_rep != nil_rep ())
-        delete m_rep;
-    }
+  ~idx_vector (void)
+  {
+    if (--m_rep->m_count == 0 && m_rep != nil_rep ())
+      delete m_rep;
+  }
 
-    idx_vector& operator = (const idx_vector& a)
-    {
-      if (this != &a)
-        {
-          if (--m_rep->m_count == 0 && m_rep != nil_rep ())
-            delete m_rep;
+  idx_vector& operator = (const idx_vector& a)
+  {
+    if (this != &a)
+      {
+        if (--m_rep->m_count == 0 && m_rep != nil_rep ())
+          delete m_rep;
 
-          m_rep = a.m_rep;
-          m_rep->m_count++;
-        }
-      return *this;
-    }
+        m_rep = a.m_rep;
+        m_rep->m_count++;
+      }
+    return *this;
+  }
 
-    idx_class_type idx_class (void) const { return m_rep->idx_class (); }
+  idx_class_type idx_class (void) const { return m_rep->idx_class (); }
 
-    octave_idx_type length (octave_idx_type n = 0) const
-    { return m_rep->length (n); }
+  octave_idx_type length (octave_idx_type n = 0) const
+  { return m_rep->length (n); }
 
-    octave_idx_type extent (octave_idx_type n) const
-    { return m_rep->extent (n); }
+  octave_idx_type extent (octave_idx_type n) const
+  { return m_rep->extent (n); }
 
-    octave_idx_type xelem (octave_idx_type n) const
-    { return m_rep->xelem (n); }
+  octave_idx_type xelem (octave_idx_type n) const
+  { return m_rep->xelem (n); }
 
-    octave_idx_type checkelem (octave_idx_type n) const
-    { return m_rep->xelem (n); }
+  octave_idx_type checkelem (octave_idx_type n) const
+  { return m_rep->xelem (n); }
 
-    octave_idx_type operator () (octave_idx_type n) const
-    { return m_rep->xelem (n); }
+  octave_idx_type operator () (octave_idx_type n) const
+  { return m_rep->xelem (n); }
 
-    // FIXME: idx_vector objects are either created successfully or an
-    // error is thrown, so this method no longer makes sense.
-    operator bool (void) const { return true; }
+  // FIXME: idx_vector objects are either created successfully or an
+  // error is thrown, so this method no longer makes sense.
+  operator bool (void) const { return true; }
 
-    bool is_colon (void) const
-    { return m_rep->idx_class () == class_colon; }
+  bool is_colon (void) const
+  { return m_rep->idx_class () == class_colon; }
 
-    bool is_scalar (void) const
-    { return m_rep->idx_class () == class_scalar; }
+  bool is_scalar (void) const
+  { return m_rep->idx_class () == class_scalar; }
 
-    bool is_range (void) const
-    { return m_rep->idx_class () == class_range; }
+  bool is_range (void) const
+  { return m_rep->idx_class () == class_range; }
 
-    bool is_colon_equiv (octave_idx_type n) const
-    { return m_rep->is_colon_equiv (n); }
+  bool is_colon_equiv (octave_idx_type n) const
+  { return m_rep->is_colon_equiv (n); }
 
-    idx_vector sorted (bool uniq = false) const
-    { return idx_vector (m_rep->sort_uniq_clone (uniq)); }
+  idx_vector sorted (bool uniq = false) const
+  { return idx_vector (m_rep->sort_uniq_clone (uniq)); }
 
-    idx_vector sorted (Array<octave_idx_type>& sidx) const
-    { return idx_vector (m_rep->sort_idx (sidx)); }
+  idx_vector sorted (Array<octave_idx_type>& sidx) const
+  { return idx_vector (m_rep->sort_idx (sidx)); }
 
-    dim_vector orig_dimensions (void) const { return m_rep->orig_dimensions (); }
+  dim_vector orig_dimensions (void) const { return m_rep->orig_dimensions (); }
 
-    octave_idx_type orig_rows (void) const
-    { return orig_dimensions () (0); }
+  octave_idx_type orig_rows (void) const
+  { return orig_dimensions () (0); }
 
-    octave_idx_type orig_columns (void) const
-    { return orig_dimensions () (1); }
+  octave_idx_type orig_columns (void) const
+  { return orig_dimensions () (1); }
 
-    int orig_empty (void) const
-    { return (! is_colon () && orig_dimensions ().any_zero ()); }
+  int orig_empty (void) const
+  { return (! is_colon () && orig_dimensions ().any_zero ()); }
 
-    // i/o
+  // i/o
 
-    std::ostream& print (std::ostream& os) const { return m_rep->print (os); }
+  std::ostream& print (std::ostream& os) const { return m_rep->print (os); }
 
-    friend std::ostream& operator << (std::ostream& os, const idx_vector& a)
-    { return a.print (os); }
+  friend std::ostream& operator << (std::ostream& os, const idx_vector& a)
+  { return a.print (os); }
 
-    // Slice with specializations.  No checking of bounds!
-    //
-    // This is equivalent to the following loop (but much faster):
-    //
-    // for (octave_idx_type i = 0; i < idx->length (n); i++)
-    //   dest[i] = src[idx(i)];
-    // return i;
-    //
-    template <typename T>
-    octave_idx_type
-    index (const T *src, octave_idx_type n, T *dest) const
-    {
-      octave_idx_type len = m_rep->length (n);
+  // Slice with specializations.  No checking of bounds!
+  //
+  // This is equivalent to the following loop (but much faster):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   dest[i] = src[idx(i)];
+  // return i;
+  //
+  template <typename T>
+  octave_idx_type
+  index (const T *src, octave_idx_type n, T *dest) const
+  {
+    octave_idx_type len = m_rep->length (n);
 
-      switch (m_rep->idx_class ())
-        {
-        case class_colon:
-          std::copy_n (src, len, dest);
-          break;
+    switch (m_rep->idx_class ())
+      {
+      case class_colon:
+        std::copy_n (src, len, dest);
+        break;
 
-        case class_range:
-          {
-            idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
-            octave_idx_type start = r->get_start ();
-            octave_idx_type step = r->get_step ();
-            const T *ssrc = src + start;
-            if (step == 1)
-              std::copy_n (ssrc, len, dest);
-            else if (step == -1)
-              std::reverse_copy (ssrc - len + 1, ssrc + 1, dest);
-            else if (step == 0)
-              std::fill_n (dest, len, *ssrc);
-            else
-              {
-                for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
-                  dest[i] = ssrc[j];
-              }
-          }
-          break;
+      case class_range:
+        {
+          idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
+          octave_idx_type start = r->get_start ();
+          octave_idx_type step = r->get_step ();
+          const T *ssrc = src + start;
+          if (step == 1)
+            std::copy_n (ssrc, len, dest);
+          else if (step == -1)
+            std::reverse_copy (ssrc - len + 1, ssrc + 1, dest);
+          else if (step == 0)
+            std::fill_n (dest, len, *ssrc);
+          else
+            {
+              for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
+                dest[i] = ssrc[j];
+            }
+        }
+        break;
 
-        case class_scalar:
-          {
-            idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
-            dest[0] = src[r->get_data ()];
-          }
-          break;
+      case class_scalar:
+        {
+          idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
+          dest[0] = src[r->get_data ()];
+        }
+        break;
 
-        case class_vector:
-          {
-            idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
-            const octave_idx_type *data = r->get_data ();
-            for (octave_idx_type i = 0; i < len; i++)
-              dest[i] = src[data[i]];
-          }
-          break;
+      case class_vector:
+        {
+          idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
+          const octave_idx_type *data = r->get_data ();
+          for (octave_idx_type i = 0; i < len; i++)
+            dest[i] = src[data[i]];
+        }
+        break;
 
-        case class_mask:
-          {
-            idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
-            const bool *data = r->get_data ();
-            octave_idx_type ext = r->extent (0);
-            for (octave_idx_type i = 0; i < ext; i++)
-              if (data[i]) *dest++ = src[i];
-          }
-          break;
+      case class_mask:
+        {
+          idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
+          const bool *data = r->get_data ();
+          octave_idx_type ext = r->extent (0);
+          for (octave_idx_type i = 0; i < ext; i++)
+            if (data[i]) *dest++ = src[i];
+        }
+        break;
 
-        default:
-          assert (false);
-          break;
-        }
+      default:
+        assert (false);
+        break;
+      }
 
-      return len;
-    }
+    return len;
+  }
 
-    // Slice assignment with specializations.  No checking of bounds!
-    //
-    // This is equivalent to the following loop (but much faster):
-    //
-    // for (octave_idx_type i = 0; i < idx->length (n); i++)
-    //   dest[idx(i)] = src[i];
-    // return i;
-    //
-    template <typename T>
-    octave_idx_type
-    assign (const T *src, octave_idx_type n, T *dest) const
-    {
-      octave_idx_type len = m_rep->length (n);
+  // Slice assignment with specializations.  No checking of bounds!
+  //
+  // This is equivalent to the following loop (but much faster):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   dest[idx(i)] = src[i];
+  // return i;
+  //
+  template <typename T>
+  octave_idx_type
+  assign (const T *src, octave_idx_type n, T *dest) const
+  {
+    octave_idx_type len = m_rep->length (n);
 
-      switch (m_rep->idx_class ())
-        {
-        case class_colon:
-          std::copy_n (src, len, dest);
-          break;
+    switch (m_rep->idx_class ())
+      {
+      case class_colon:
+        std::copy_n (src, len, dest);
+        break;
 
-        case class_range:
-          {
-            idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
-            octave_idx_type start = r->get_start ();
-            octave_idx_type step = r->get_step ();
-            T *sdest = dest + start;
-            if (step == 1)
-              std::copy_n (src, len, sdest);
-            else if (step == -1)
-              std::reverse_copy (src, src + len, sdest - len + 1);
-            else
-              {
-                for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
-                  sdest[j] = src[i];
-              }
-          }
-          break;
+      case class_range:
+        {
+          idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
+          octave_idx_type start = r->get_start ();
+          octave_idx_type step = r->get_step ();
+          T *sdest = dest + start;
+          if (step == 1)
+            std::copy_n (src, len, sdest);
+          else if (step == -1)
+            std::reverse_copy (src, src + len, sdest - len + 1);
+          else
+            {
+              for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
+                sdest[j] = src[i];
+            }
+        }
+        break;
 
-        case class_scalar:
-          {
-            idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
-            dest[r->get_data ()] = src[0];
-          }
-          break;
+      case class_scalar:
+        {
+          idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
+          dest[r->get_data ()] = src[0];
+        }
+        break;
 
-        case class_vector:
-          {
-            idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
-            const octave_idx_type *data = r->get_data ();
-            for (octave_idx_type i = 0; i < len; i++)
-              dest[data[i]] = src[i];
-          }
-          break;
+      case class_vector:
+        {
+          idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
+          const octave_idx_type *data = r->get_data ();
+          for (octave_idx_type i = 0; i < len; i++)
+            dest[data[i]] = src[i];
+        }
+        break;
 
-        case class_mask:
-          {
-            idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
-            const bool *data = r->get_data ();
-            octave_idx_type ext = r->extent (0);
-            for (octave_idx_type i = 0; i < ext; i++)
-              if (data[i]) dest[i] = *src++;
-          }
-          break;
+      case class_mask:
+        {
+          idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
+          const bool *data = r->get_data ();
+          octave_idx_type ext = r->extent (0);
+          for (octave_idx_type i = 0; i < ext; i++)
+            if (data[i]) dest[i] = *src++;
+        }
+        break;
 
-        default:
-          assert (false);
-          break;
-        }
+      default:
+        assert (false);
+        break;
+      }
 
-      return len;
-    }
+    return len;
+  }
 
-    // Slice fill with specializations.  No checking of bounds!
-    //
-    // This is equivalent to the following loop (but much faster):
-    //
-    // for (octave_idx_type i = 0; i < idx->length (n); i++)
-    //   dest[idx(i)] = val;
-    // return i;
-    //
-    template <typename T>
-    octave_idx_type
-    fill (const T& val, octave_idx_type n, T *dest) const
-    {
-      octave_idx_type len = m_rep->length (n);
+  // Slice fill with specializations.  No checking of bounds!
+  //
+  // This is equivalent to the following loop (but much faster):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   dest[idx(i)] = val;
+  // return i;
+  //
+  template <typename T>
+  octave_idx_type
+  fill (const T& val, octave_idx_type n, T *dest) const
+  {
+    octave_idx_type len = m_rep->length (n);
 
-      switch (m_rep->idx_class ())
-        {
-        case class_colon:
-          std::fill_n (dest, len, val);
-          break;
+    switch (m_rep->idx_class ())
+      {
+      case class_colon:
+        std::fill_n (dest, len, val);
+        break;
 
-        case class_range:
-          {
-            idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
-            octave_idx_type start = r->get_start ();
-            octave_idx_type step = r->get_step ();
-            T *sdest = dest + start;
-            if (step == 1)
-              std::fill_n (sdest, len, val);
-            else if (step == -1)
-              std::fill (sdest - len + 1, sdest + 1, val);
-            else
-              {
-                for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
-                  sdest[j] = val;
-              }
-          }
-          break;
+      case class_range:
+        {
+          idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
+          octave_idx_type start = r->get_start ();
+          octave_idx_type step = r->get_step ();
+          T *sdest = dest + start;
+          if (step == 1)
+            std::fill_n (sdest, len, val);
+          else if (step == -1)
+            std::fill (sdest - len + 1, sdest + 1, val);
+          else
+            {
+              for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
+                sdest[j] = val;
+            }
+        }
+        break;
 
-        case class_scalar:
-          {
-            idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
-            dest[r->get_data ()] = val;
-          }
-          break;
+      case class_scalar:
+        {
+          idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
+          dest[r->get_data ()] = val;
+        }
+        break;
 
-        case class_vector:
-          {
-            idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
-            const octave_idx_type *data = r->get_data ();
-            for (octave_idx_type i = 0; i < len; i++)
-              dest[data[i]] = val;
-          }
-          break;
+      case class_vector:
+        {
+          idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
+          const octave_idx_type *data = r->get_data ();
+          for (octave_idx_type i = 0; i < len; i++)
+            dest[data[i]] = val;
+        }
+        break;
 
-        case class_mask:
-          {
-            idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
-            const bool *data = r->get_data ();
-            octave_idx_type ext = r->extent (0);
-            for (octave_idx_type i = 0; i < ext; i++)
-              if (data[i]) dest[i] = val;
-          }
-          break;
+      case class_mask:
+        {
+          idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
+          const bool *data = r->get_data ();
+          octave_idx_type ext = r->extent (0);
+          for (octave_idx_type i = 0; i < ext; i++)
+            if (data[i]) dest[i] = val;
+        }
+        break;
 
-        default:
-          assert (false);
-          break;
-        }
+      default:
+        assert (false);
+        break;
+      }
 
-      return len;
-    }
+    return len;
+  }
 
-    // Generic non-breakable indexed loop.  The loop body should be
-    // encapsulated in a single functor body.  This is equivalent to the
-    // following loop (but faster, at least for simple inlined bodies):
-    //
-    // for (octave_idx_type i = 0; i < idx->length (n); i++) body (idx(i));
+  // Generic non-breakable indexed loop.  The loop body should be
+  // encapsulated in a single functor body.  This is equivalent to the
+  // following loop (but faster, at least for simple inlined bodies):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++) body (idx(i));
 
-    template <typename Functor>
-    void
-    loop (octave_idx_type n, Functor body) const
-    {
-      octave_idx_type len = m_rep->length (n);
+  template <typename Functor>
+  void
+  loop (octave_idx_type n, Functor body) const
+  {
+    octave_idx_type len = m_rep->length (n);
 
-      switch (m_rep->idx_class ())
+    switch (m_rep->idx_class ())
+      {
+      case class_colon:
+        for (octave_idx_type i = 0; i < len; i++) body (i);
+        break;
+
+      case class_range:
         {
-        case class_colon:
-          for (octave_idx_type i = 0; i < len; i++) body (i);
-          break;
-
-        case class_range:
-          {
-            idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
-            octave_idx_type start = r->get_start ();
-            octave_idx_type step = r->get_step ();
-            octave_idx_type i, j;
-            if (step == 1)
-              for (i = start, j = start + len; i < j; i++) body (i);
-            else if (step == -1)
-              for (i = start, j = start - len; i > j; i--) body (i);
-            else
-              for (i = 0, j = start; i < len; i++, j += step) body (j);
-          }
-          break;
+          idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
+          octave_idx_type start = r->get_start ();
+          octave_idx_type step = r->get_step ();
+          octave_idx_type i, j;
+          if (step == 1)
+            for (i = start, j = start + len; i < j; i++) body (i);
+          else if (step == -1)
+            for (i = start, j = start - len; i > j; i--) body (i);
+          else
+            for (i = 0, j = start; i < len; i++, j += step) body (j);
+        }
+        break;
 
-        case class_scalar:
-          {
-            idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
-            body (r->get_data ());
-          }
-          break;
+      case class_scalar:
+        {
+          idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
+          body (r->get_data ());
+        }
+        break;
 
-        case class_vector:
-          {
-            idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
-            const octave_idx_type *data = r->get_data ();
-            for (octave_idx_type i = 0; i < len; i++) body (data[i]);
-          }
-          break;
+      case class_vector:
+        {
+          idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
+          const octave_idx_type *data = r->get_data ();
+          for (octave_idx_type i = 0; i < len; i++) body (data[i]);
+        }
+        break;
 
-        case class_mask:
-          {
-            idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
-            const bool *data = r->get_data ();
-            octave_idx_type ext = r->extent (0);
-            for (octave_idx_type i = 0; i < ext; i++)
-              if (data[i]) body (i);
-          }
-          break;
+      case class_mask:
+        {
+          idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
+          const bool *data = r->get_data ();
+          octave_idx_type ext = r->extent (0);
+          for (octave_idx_type i = 0; i < ext; i++)
+            if (data[i]) body (i);
+        }
+        break;
 
-        default:
-          assert (false);
-          break;
-        }
+      default:
+        assert (false);
+        break;
+      }
 
-    }
+  }
 
-    // Generic breakable indexed loop.  The loop body should be
-    // encapsulated in a single functor body.  This is equivalent to the
-    // following loop (but faster, at least for simple inlined bodies):
-    //
-    // for (octave_idx_type i = 0; i < idx->length (n); i++)
-    //   if (body (idx(i))) break;
-    // return i;
-    //
+  // Generic breakable indexed loop.  The loop body should be
+  // encapsulated in a single functor body.  This is equivalent to the
+  // following loop (but faster, at least for simple inlined bodies):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   if (body (idx(i))) break;
+  // return i;
+  //
 
-    template <typename Functor>
-    octave_idx_type
-    bloop (octave_idx_type n, Functor body) const
-    {
-      octave_idx_type len = m_rep->length (n), ret;
+  template <typename Functor>
+  octave_idx_type
+  bloop (octave_idx_type n, Functor body) const
+  {
+    octave_idx_type len = m_rep->length (n), ret;
 
-      switch (m_rep->idx_class ())
+    switch (m_rep->idx_class ())
+      {
+      case class_colon:
         {
-        case class_colon:
-          {
-            octave_idx_type i;
-            for (i = 0; i < len && body (i); i++) ;
-            ret = i;
-          }
-          break;
+          octave_idx_type i;
+          for (i = 0; i < len && body (i); i++) ;
+          ret = i;
+        }
+        break;
 
-        case class_range:
-          {
-            idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
-            octave_idx_type start = r->get_start ();
-            octave_idx_type step = r->get_step ();
-            octave_idx_type i, j;
-            if (step == 1)
-              for (i = start, j = start + len; i < j && body (i); i++) ;
-            else if (step == -1)
-              for (i = start, j = start - len; i > j && body (i); i--) ;
-            else
-              for (i = 0, j = start; i < len && body (j); i++, j += step) ;
-            ret = i;
-          }
-          break;
+      case class_range:
+        {
+          idx_range_rep *r = dynamic_cast<idx_range_rep *> (m_rep);
+          octave_idx_type start = r->get_start ();
+          octave_idx_type step = r->get_step ();
+          octave_idx_type i, j;
+          if (step == 1)
+            for (i = start, j = start + len; i < j && body (i); i++) ;
+          else if (step == -1)
+            for (i = start, j = start - len; i > j && body (i); i--) ;
+          else
+            for (i = 0, j = start; i < len && body (j); i++, j += step) ;
+          ret = i;
+        }
+        break;
 
-        case class_scalar:
-          {
-            idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
-            ret = (body (r->get_data ()) ? 1 : 0);
-          }
-          break;
+      case class_scalar:
+        {
+          idx_scalar_rep *r = dynamic_cast<idx_scalar_rep *> (m_rep);
+          ret = (body (r->get_data ()) ? 1 : 0);
+        }
+        break;
 
-        case class_vector:
-          {
-            idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
-            const octave_idx_type *data = r->get_data ();
-            octave_idx_type i;
-            for (i = 0; i < len && body (data[i]); i++) ;
-            ret = i;
-          }
-          break;
+      case class_vector:
+        {
+          idx_vector_rep *r = dynamic_cast<idx_vector_rep *> (m_rep);
+          const octave_idx_type *data = r->get_data ();
+          octave_idx_type i;
+          for (i = 0; i < len && body (data[i]); i++) ;
+          ret = i;
+        }
+        break;
 
-        case class_mask:
-          {
-            idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
-            const bool *data = r->get_data ();
-            octave_idx_type ext = r->extent (0);
-            octave_idx_type j = 0;
-            for (octave_idx_type i = 0; i < ext; i++)
-              {
-                if (data[i])
-                  {
-                    if (body (i))
-                      break;
-                    else
-                      j++;
-                  }
-              }
+      case class_mask:
+        {
+          idx_mask_rep *r = dynamic_cast<idx_mask_rep *> (m_rep);
+          const bool *data = r->get_data ();
+          octave_idx_type ext = r->extent (0);
+          octave_idx_type j = 0;
+          for (octave_idx_type i = 0; i < ext; i++)
+            {
+              if (data[i])
+                {
+                  if (body (i))
+                    break;
+                  else
+                    j++;
+                }
+            }
 
-            ret = j;
-          }
-          break;
-
-        default:
-          assert (false);
-          break;
+          ret = j;
         }
+        break;
 
-      return ret;
-    }
+      default:
+        assert (false);
+        break;
+      }
+
+    return ret;
+  }
 
-    // Rationale:
-    // This method is the key to "smart indexing".  When indexing cartesian
-    // arrays, sometimes consecutive index vectors can be reduced into a
-    // single index.  If rows (A) = k and i.maybe_reduce (j) gives k, then
-    // A(i,j)(:) is equal to A(k)(:).
+  // Rationale:
+  // This method is the key to "smart indexing".  When indexing cartesian
+  // arrays, sometimes consecutive index vectors can be reduced into a
+  // single index.  If rows (A) = k and i.maybe_reduce (j) gives k, then
+  // A(i,j)(:) is equal to A(k)(:).
 
-    // If the next index can be reduced, returns true and updates this.
-    OCTAVE_API bool
-    maybe_reduce (octave_idx_type n, const idx_vector& j, octave_idx_type nj);
-
-    OCTAVE_API bool
-    is_cont_range (octave_idx_type n, octave_idx_type& l,
-                   octave_idx_type& u) const;
+  // If the next index can be reduced, returns true and updates this.
+  OCTAVE_API bool
+  maybe_reduce (octave_idx_type n, const idx_vector& j, octave_idx_type nj);
 
-    // Returns the increment for ranges and colon, 0 for scalars and empty
-    // vectors, 1st difference otherwise.
-    OCTAVE_API octave_idx_type increment (void) const;
+  OCTAVE_API bool
+  is_cont_range (octave_idx_type n, octave_idx_type& l,
+                 octave_idx_type& u) const;
 
-    OCTAVE_API idx_vector
-    complement (octave_idx_type n) const;
-
-    OCTAVE_API bool is_permutation (octave_idx_type n) const;
+  // Returns the increment for ranges and colon, 0 for scalars and empty
+  // vectors, 1st difference otherwise.
+  OCTAVE_API octave_idx_type increment (void) const;
 
-    // Returns the inverse permutation.  If this is not a permutation on 1:n, the
-    // result is undefined (but no error unless extent () != n).
-    OCTAVE_API idx_vector inverse_permutation (octave_idx_type n) const;
+  OCTAVE_API idx_vector
+  complement (octave_idx_type n) const;
+
+  OCTAVE_API bool is_permutation (octave_idx_type n) const;
 
-    // Copies all the indices to a given array.  Not allowed for colons.
-    OCTAVE_API void copy_data (octave_idx_type *data) const;
+  // Returns the inverse permutation.  If this is not a permutation on 1:n, the
+  // result is undefined (but no error unless extent () != n).
+  OCTAVE_API idx_vector inverse_permutation (octave_idx_type n) const;
 
-    // If the index is a mask, convert it to index vector.
-    OCTAVE_API idx_vector unmask (void) const;
+  // Copies all the indices to a given array.  Not allowed for colons.
+  OCTAVE_API void copy_data (octave_idx_type *data) const;
 
-    // Unconverts the index to a scalar, Range, double array or a mask.
-    OCTAVE_API void
-    unconvert (idx_class_type& iclass, double& scalar, range<double>& range,
-               Array<double>& array, Array<bool>& mask) const;
+  // If the index is a mask, convert it to index vector.
+  OCTAVE_API idx_vector unmask (void) const;
 
-    OCTAVE_API Array<octave_idx_type> as_array (void) const;
+  // Unconverts the index to a scalar, Range, double array or a mask.
+  OCTAVE_API void
+  unconvert (idx_class_type& iclass, double& scalar, range<double>& range,
+             Array<double>& array, Array<bool>& mask) const;
 
-    // Raw pointer to index array.  This is non-const because it may be
-    // necessary to mutate the index.
-    const OCTAVE_API octave_idx_type * raw (void);
-
-    OCTAVE_API bool isvector (void) const;
+  OCTAVE_API Array<octave_idx_type> as_array (void) const;
 
-    // FIXME: these are here for compatibility.  They should be removed
-    // when no longer in use.
+  // Raw pointer to index array.  This is non-const because it may be
+  // necessary to mutate the index.
+  const OCTAVE_API octave_idx_type * raw (void);
 
-    octave_idx_type elem (octave_idx_type n) const
-    { return (*this) (n); }
+  OCTAVE_API bool isvector (void) const;
+
+  // FIXME: these are here for compatibility.  They should be removed
+  // when no longer in use.
 
-    bool is_colon_equiv (octave_idx_type n, int) const
-    { return is_colon_equiv (n); }
+  octave_idx_type elem (octave_idx_type n) const
+  { return (*this) (n); }
 
-    OCTAVE_API octave_idx_type
-    freeze (octave_idx_type z_len, const char *tag, bool resize_ok = false);
+  bool is_colon_equiv (octave_idx_type n, int) const
+  { return is_colon_equiv (n); }
 
-    void sort (bool uniq = false)
-    { *this = sorted (uniq); }
+  OCTAVE_API octave_idx_type
+  freeze (octave_idx_type z_len, const char *tag, bool resize_ok = false);
 
-    OCTAVE_API octave_idx_type ones_count (void) const;
+  void sort (bool uniq = false)
+  { *this = sorted (uniq); }
 
-    octave_idx_type max (void) const { return extent (1) - 1; }
+  OCTAVE_API octave_idx_type ones_count (void) const;
 
-  private:
+  octave_idx_type max (void) const { return extent (1) - 1; }
+
+private:
 
-    idx_base_rep *m_rep;
+  idx_base_rep *m_rep;
 
-  };
+};
 
 OCTAVE_END_NAMESPACE(octave)