From f3643eec57a114ff444237027b2f61034a961ea8 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Fri, 19 Feb 2016 22:15:01 +0100
Subject: [PATCH] Add typedefs for the return type of all block methods.

---
 Eigen/src/plugins/BlockMethods.h | 145 ++++++++++++++++---------------
 1 file changed, 75 insertions(+), 70 deletions(-)

diff --git a/Eigen/src/plugins/BlockMethods.h b/Eigen/src/plugins/BlockMethods.h
index 9b7fdc4aa..632094e15 100644
--- a/Eigen/src/plugins/BlockMethods.h
+++ b/Eigen/src/plugins/BlockMethods.h
@@ -8,7 +8,6 @@
 // Public License v. 2.0. If a copy of the MPL was not distributed
 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-
 #ifndef EIGEN_PARSED_BY_DOXYGEN
 
 /** \internal expression type of a column */
@@ -29,6 +28,12 @@ template<int N> struct ConstNColsBlockXpr { typedef const Block<const Derived, i
 /** \internal expression type of a block of whole rows */
 template<int N> struct NRowsBlockXpr { typedef Block<Derived, N, internal::traits<Derived>::ColsAtCompileTime, IsRowMajor> Type; };
 template<int N> struct ConstNRowsBlockXpr { typedef const Block<const Derived, N, internal::traits<Derived>::ColsAtCompileTime, IsRowMajor> Type; };
+/** \internal expression of a block */
+typedef Block<Derived> BlockXpr;
+typedef const Block<const Derived> ConstBlockXpr;
+/** \internal expression of a block of fixed sizes */
+template<int Rows, int Cols> struct FixedBlockXpr { typedef Block<Derived,Rows,Cols> Type; };
+template<int Rows, int Cols> struct ConstFixedBlockXpr { typedef Block<const Derived,Rows,Cols> Type; };
 
 typedef VectorBlock<Derived> SegmentReturnType;
 typedef const VectorBlock<const Derived> ConstSegmentReturnType;
@@ -54,16 +59,16 @@ template<int Size> struct ConstFixedSegmentReturnType { typedef const VectorBloc
   * \sa class Block, block(Index,Index)
   */
 EIGEN_DEVICE_FUNC
-inline Block<Derived> block(Index startRow, Index startCol, Index blockRows, Index blockCols)
+inline BlockXpr block(Index startRow, Index startCol, Index blockRows, Index blockCols)
 {
-  return Block<Derived>(derived(), startRow, startCol, blockRows, blockCols);
+  return BlockXpr(derived(), startRow, startCol, blockRows, blockCols);
 }
 
 /** This is the const version of block(Index,Index,Index,Index). */
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived> block(Index startRow, Index startCol, Index blockRows, Index blockCols) const
+inline const ConstBlockXpr block(Index startRow, Index startCol, Index blockRows, Index blockCols) const
 {
-  return Block<const Derived>(derived(), startRow, startCol, blockRows, blockCols);
+  return ConstBlockXpr(derived(), startRow, startCol, blockRows, blockCols);
 }
 
 
@@ -80,16 +85,16 @@ inline const Block<const Derived> block(Index startRow, Index startCol, Index bl
   * \sa class Block, block(Index,Index,Index,Index)
   */
 EIGEN_DEVICE_FUNC
-inline Block<Derived> topRightCorner(Index cRows, Index cCols)
+inline BlockXpr topRightCorner(Index cRows, Index cCols)
 {
-  return Block<Derived>(derived(), 0, cols() - cCols, cRows, cCols);
+  return BlockXpr(derived(), 0, cols() - cCols, cRows, cCols);
 }
 
 /** This is the const version of topRightCorner(Index, Index).*/
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived> topRightCorner(Index cRows, Index cCols) const
+inline const ConstBlockXpr topRightCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived>(derived(), 0, cols() - cCols, cRows, cCols);
+  return ConstBlockXpr(derived(), 0, cols() - cCols, cRows, cCols);
 }
 
 /** \returns an expression of a fixed-size top-right corner of *this.
@@ -104,17 +109,17 @@ inline const Block<const Derived> topRightCorner(Index cRows, Index cCols) const
   */
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline Block<Derived, CRows, CCols> topRightCorner()
+inline typename FixedBlockXpr<CRows,CCols>::Type topRightCorner()
 {
-  return Block<Derived, CRows, CCols>(derived(), 0, cols() - CCols);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), 0, cols() - CCols);
 }
 
 /** This is the const version of topRightCorner<int, int>().*/
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived, CRows, CCols> topRightCorner() const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topRightCorner() const
 {
-  return Block<const Derived, CRows, CCols>(derived(), 0, cols() - CCols);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), 0, cols() - CCols);
 }
 
 /** \returns an expression of a top-right corner of *this.
@@ -135,16 +140,16 @@ inline const Block<const Derived, CRows, CCols> topRightCorner() const
   * \sa class Block
   */
 template<int CRows, int CCols>
-inline Block<Derived, CRows, CCols> topRightCorner(Index cRows, Index cCols)
+inline typename FixedBlockXpr<CRows,CCols>::Type topRightCorner(Index cRows, Index cCols)
 {
-  return Block<Derived, CRows, CCols>(derived(), 0, cols() - cCols, cRows, cCols);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), 0, cols() - cCols, cRows, cCols);
 }
 
 /** This is the const version of topRightCorner<int, int>(Index, Index).*/
 template<int CRows, int CCols>
-inline const Block<const Derived, CRows, CCols> topRightCorner(Index cRows, Index cCols) const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topRightCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived, CRows, CCols>(derived(), 0, cols() - cCols, cRows, cCols);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), 0, cols() - cCols, cRows, cCols);
 }
 
 
@@ -160,16 +165,16 @@ inline const Block<const Derived, CRows, CCols> topRightCorner(Index cRows, Inde
   * \sa class Block, block(Index,Index,Index,Index)
   */
 EIGEN_DEVICE_FUNC
-inline Block<Derived> topLeftCorner(Index cRows, Index cCols)
+inline BlockXpr topLeftCorner(Index cRows, Index cCols)
 {
-  return Block<Derived>(derived(), 0, 0, cRows, cCols);
+  return BlockXpr(derived(), 0, 0, cRows, cCols);
 }
 
 /** This is the const version of topLeftCorner(Index, Index).*/
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived> topLeftCorner(Index cRows, Index cCols) const
+inline const ConstBlockXpr topLeftCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived>(derived(), 0, 0, cRows, cCols);
+  return ConstBlockXpr(derived(), 0, 0, cRows, cCols);
 }
 
 /** \returns an expression of a fixed-size top-left corner of *this.
@@ -183,17 +188,17 @@ inline const Block<const Derived> topLeftCorner(Index cRows, Index cCols) const
   */
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline Block<Derived, CRows, CCols> topLeftCorner()
+inline typename FixedBlockXpr<CRows,CCols>::Type topLeftCorner()
 {
-  return Block<Derived, CRows, CCols>(derived(), 0, 0);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), 0, 0);
 }
 
 /** This is the const version of topLeftCorner<int, int>().*/
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived, CRows, CCols> topLeftCorner() const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topLeftCorner() const
 {
-  return Block<const Derived, CRows, CCols>(derived(), 0, 0);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), 0, 0);
 }
 
 /** \returns an expression of a top-left corner of *this.
@@ -214,16 +219,16 @@ inline const Block<const Derived, CRows, CCols> topLeftCorner() const
   * \sa class Block
   */
 template<int CRows, int CCols>
-inline Block<Derived, CRows, CCols> topLeftCorner(Index cRows, Index cCols)
+inline typename FixedBlockXpr<CRows,CCols>::Type topLeftCorner(Index cRows, Index cCols)
 {
-  return Block<Derived, CRows, CCols>(derived(), 0, 0, cRows, cCols);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), 0, 0, cRows, cCols);
 }
 
 /** This is the const version of topLeftCorner<int, int>(Index, Index).*/
 template<int CRows, int CCols>
-inline const Block<const Derived, CRows, CCols> topLeftCorner(Index cRows, Index cCols) const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topLeftCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived, CRows, CCols>(derived(), 0, 0, cRows, cCols);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), 0, 0, cRows, cCols);
 }
 
 
@@ -239,16 +244,16 @@ inline const Block<const Derived, CRows, CCols> topLeftCorner(Index cRows, Index
   * \sa class Block, block(Index,Index,Index,Index)
   */
 EIGEN_DEVICE_FUNC
-inline Block<Derived> bottomRightCorner(Index cRows, Index cCols)
+inline BlockXpr bottomRightCorner(Index cRows, Index cCols)
 {
-  return Block<Derived>(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
+  return BlockXpr(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
 }
 
 /** This is the const version of bottomRightCorner(Index, Index).*/
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived> bottomRightCorner(Index cRows, Index cCols) const
+inline const ConstBlockXpr bottomRightCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived>(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
+  return ConstBlockXpr(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
 }
 
 /** \returns an expression of a fixed-size bottom-right corner of *this.
@@ -262,17 +267,17 @@ inline const Block<const Derived> bottomRightCorner(Index cRows, Index cCols) co
   */
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline Block<Derived, CRows, CCols> bottomRightCorner()
+inline typename FixedBlockXpr<CRows,CCols>::Type bottomRightCorner()
 {
-  return Block<Derived, CRows, CCols>(derived(), rows() - CRows, cols() - CCols);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), rows() - CRows, cols() - CCols);
 }
 
 /** This is the const version of bottomRightCorner<int, int>().*/
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived, CRows, CCols> bottomRightCorner() const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomRightCorner() const
 {
-  return Block<const Derived, CRows, CCols>(derived(), rows() - CRows, cols() - CCols);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), rows() - CRows, cols() - CCols);
 }
 
 /** \returns an expression of a bottom-right corner of *this.
@@ -293,16 +298,16 @@ inline const Block<const Derived, CRows, CCols> bottomRightCorner() const
   * \sa class Block
   */
 template<int CRows, int CCols>
-inline Block<Derived, CRows, CCols> bottomRightCorner(Index cRows, Index cCols)
+inline typename FixedBlockXpr<CRows,CCols>::Type bottomRightCorner(Index cRows, Index cCols)
 {
-  return Block<Derived, CRows, CCols>(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
 }
 
 /** This is the const version of bottomRightCorner<int, int>(Index, Index).*/
 template<int CRows, int CCols>
-inline const Block<const Derived, CRows, CCols> bottomRightCorner(Index cRows, Index cCols) const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomRightCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived, CRows, CCols>(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
 }
 
 
@@ -318,16 +323,16 @@ inline const Block<const Derived, CRows, CCols> bottomRightCorner(Index cRows, I
   * \sa class Block, block(Index,Index,Index,Index)
   */
 EIGEN_DEVICE_FUNC
-inline Block<Derived> bottomLeftCorner(Index cRows, Index cCols)
+inline BlockXpr bottomLeftCorner(Index cRows, Index cCols)
 {
-  return Block<Derived>(derived(), rows() - cRows, 0, cRows, cCols);
+  return BlockXpr(derived(), rows() - cRows, 0, cRows, cCols);
 }
 
 /** This is the const version of bottomLeftCorner(Index, Index).*/
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived> bottomLeftCorner(Index cRows, Index cCols) const
+inline const ConstBlockXpr bottomLeftCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived>(derived(), rows() - cRows, 0, cRows, cCols);
+  return ConstBlockXpr(derived(), rows() - cRows, 0, cRows, cCols);
 }
 
 /** \returns an expression of a fixed-size bottom-left corner of *this.
@@ -341,17 +346,17 @@ inline const Block<const Derived> bottomLeftCorner(Index cRows, Index cCols) con
   */
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline Block<Derived, CRows, CCols> bottomLeftCorner()
+inline typename FixedBlockXpr<CRows,CCols>::Type bottomLeftCorner()
 {
-  return Block<Derived, CRows, CCols>(derived(), rows() - CRows, 0);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), rows() - CRows, 0);
 }
 
 /** This is the const version of bottomLeftCorner<int, int>().*/
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived, CRows, CCols> bottomLeftCorner() const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomLeftCorner() const
 {
-  return Block<const Derived, CRows, CCols>(derived(), rows() - CRows, 0);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), rows() - CRows, 0);
 }
 
 /** \returns an expression of a bottom-left corner of *this.
@@ -372,16 +377,16 @@ inline const Block<const Derived, CRows, CCols> bottomLeftCorner() const
   * \sa class Block
   */
 template<int CRows, int CCols>
-inline Block<Derived, CRows, CCols> bottomLeftCorner(Index cRows, Index cCols)
+inline typename FixedBlockXpr<CRows,CCols>::Type bottomLeftCorner(Index cRows, Index cCols)
 {
-  return Block<Derived, CRows, CCols>(derived(), rows() - cRows, 0, cRows, cCols);
+  return typename FixedBlockXpr<CRows,CCols>::Type(derived(), rows() - cRows, 0, cRows, cCols);
 }
 
 /** This is the const version of bottomLeftCorner<int, int>(Index, Index).*/
 template<int CRows, int CCols>
-inline const Block<const Derived, CRows, CCols> bottomLeftCorner(Index cRows, Index cCols) const
+inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomLeftCorner(Index cRows, Index cCols) const
 {
-  return Block<const Derived, CRows, CCols>(derived(), rows() - cRows, 0, cRows, cCols);
+  return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), rows() - cRows, 0, cRows, cCols);
 }
 
 
@@ -704,7 +709,7 @@ inline typename ConstNColsBlockXpr<N>::Type middleCols(Index startCol, Index n =
 
 /** \returns a fixed-size expression of a block in *this.
   *
-  * The template parameters \a BlockRows and \a BlockCols are the number of
+  * The template parameters \a NRows and \a NCols are the number of
   * rows and columns in the block.
   *
   * \param startRow the first row in the block
@@ -718,25 +723,25 @@ inline typename ConstNColsBlockXpr<N>::Type middleCols(Index startCol, Index n =
   *
   * \sa class Block, block(Index,Index,Index,Index)
   */
-template<int BlockRows, int BlockCols>
+template<int NRows, int NCols>
 EIGEN_DEVICE_FUNC
-inline Block<Derived, BlockRows, BlockCols> block(Index startRow, Index startCol)
+inline typename FixedBlockXpr<NRows,NCols>::Type block(Index startRow, Index startCol)
 {
-  return Block<Derived, BlockRows, BlockCols>(derived(), startRow, startCol);
+  return typename FixedBlockXpr<NRows,NCols>::Type(derived(), startRow, startCol);
 }
 
 /** This is the const version of block<>(Index, Index). */
-template<int BlockRows, int BlockCols>
+template<int NRows, int NCols>
 EIGEN_DEVICE_FUNC
-inline const Block<const Derived, BlockRows, BlockCols> block(Index startRow, Index startCol) const
+inline const typename ConstFixedBlockXpr<NRows,NCols>::Type block(Index startRow, Index startCol) const
 {
-  return Block<const Derived, BlockRows, BlockCols>(derived(), startRow, startCol);
+  return typename ConstFixedBlockXpr<NRows,NCols>::Type(derived(), startRow, startCol);
 }
 
 /** \returns an expression of a block in *this.
   *
-  * \tparam BlockRows number of rows in block as specified at compile-time
-  * \tparam BlockCols number of columns in block as specified at compile-time
+  * \tparam NRows number of rows in block as specified at compile-time
+  * \tparam NCols number of columns in block as specified at compile-time
   * \param  startRow  the first row in the block
   * \param  startCol  the first column in the block
   * \param  blockRows number of rows in block as specified at run-time
@@ -744,27 +749,27 @@ inline const Block<const Derived, BlockRows, BlockCols> block(Index startRow, In
   *
   * This function is mainly useful for blocks where the number of rows is specified at compile-time
   * and the number of columns is specified at run-time, or vice versa. The compile-time and run-time
-  * information should not contradict. In other words, \a blockRows should equal \a BlockRows unless
-  * \a BlockRows is \a Dynamic, and the same for the number of columns.
+  * information should not contradict. In other words, \a blockRows should equal \a NRows unless
+  * \a NRows is \a Dynamic, and the same for the number of columns.
   *
   * Example: \include MatrixBase_template_int_int_block_int_int_int_int.cpp
   * Output: \verbinclude MatrixBase_template_int_int_block_int_int_int_int.cpp
   *
   * \sa class Block, block(Index,Index,Index,Index)
   */
-template<int BlockRows, int BlockCols>
-inline Block<Derived, BlockRows, BlockCols> block(Index startRow, Index startCol, 
+template<int NRows, int NCols>
+inline typename FixedBlockXpr<NRows,NCols>::Type block(Index startRow, Index startCol,
                                                   Index blockRows, Index blockCols)
 {
-  return Block<Derived, BlockRows, BlockCols>(derived(), startRow, startCol, blockRows, blockCols);
+  return typename FixedBlockXpr<NRows,NCols>::Type(derived(), startRow, startCol, blockRows, blockCols);
 }
 
 /** This is the const version of block<>(Index, Index, Index, Index). */
-template<int BlockRows, int BlockCols>
-inline const Block<const Derived, BlockRows, BlockCols> block(Index startRow, Index startCol,
+template<int NRows, int NCols>
+inline const typename ConstFixedBlockXpr<NRows,NCols>::Type block(Index startRow, Index startCol,
                                                               Index blockRows, Index blockCols) const
 {
-  return Block<const Derived, BlockRows, BlockCols>(derived(), startRow, startCol, blockRows, blockCols);
+  return typename ConstFixedBlockXpr<NRows,NCols>::Type(derived(), startRow, startCol, blockRows, blockCols);
 }
 
 /** \returns an expression of the \a i-th column of *this. Note that the numbering starts at 0.