LineAndColumn: move to it's own header and add operator[+-]=?

LineAndColumn is now a template so that WindowCoords and BufferCoords
cannot be added together.

src/buffer.cc

@@ -3,6 +3,7 @@
 #include "buffer_manager.hh"
 #include "window.hh"
 #include "assert.hh"
+#include "utils.hh"
 
 #include <algorithm>
 

src/buffer.hh

@@ -6,7 +6,7 @@
 #include <list>
 #include <memory>
 
-#include "utils.hh"
+#include "line_and_column.hh"
 
 namespace Kakoune
 {
@@ -19,7 +19,7 @@ typedef int      BufferSize;
 typedef char     BufferChar;
 typedef std::basic_string<BufferChar> BufferString;
 
-struct BufferCoord : LineAndColumn
+struct BufferCoord : LineAndColumn<BufferCoord>
 {
     BufferCoord(int line = 0, int column = 0)
         : LineAndColumn(line, column) {}

src/display_buffer.cc

@@ -7,9 +7,4 @@ DisplayBuffer::DisplayBuffer()
 {
 }
 
-LineAndColumn DisplayBuffer::dimensions() const
-{
-    return LineAndColumn();
-}
-
 }

src/display_buffer.hh

@@ -4,8 +4,6 @@
 #include <string>
 #include <vector>
 
-#include "buffer.hh"
-
 namespace Kakoune
 {
 
@@ -36,8 +34,6 @@ public:
 
     DisplayBuffer();
 
-    LineAndColumn dimensions() const;
-
     void clear() { m_atoms.clear(); }
     void append(const DisplayAtom& atom) { m_atoms.push_back(atom); }
 

src/line_and_column.hh

@@ -0,0 +1,43 @@
+#ifndef line_and_column_hh_INCLUDED
+#define line_and_column_hh_INCLUDED
+
+namespace Kakoune
+{
+
+template<typename EffectiveType>
+struct LineAndColumn
+{
+    int line;
+    int column;
+
+    LineAndColumn(int line = 0, int column = 0)
+        : line(line), column(column) {}
+
+    EffectiveType operator+(const EffectiveType& other) const
+    {
+        return EffectiveType(line + other.line, column + other.column);
+    }
+
+    EffectiveType& operator+=(const EffectiveType& other)
+    {
+        line   += other.line;
+        column += other.column;
+        return *this;
+    }
+
+    EffectiveType operator-(const EffectiveType& other) const
+    {
+        return EffectiveType(line + other.line, column + other.column);
+    }
+
+    EffectiveType& operator-=(const EffectiveType& other)
+    {
+        line   += other.line;
+        column += other.column;
+        return *this;
+    }
+};
+
+}
+
+#endif // line_and_column_hh_INCLUDED

src/utils.hh

@@ -8,15 +8,6 @@
 namespace Kakoune
 {
 
-struct LineAndColumn
-{
-    int line;
-    int column;
-
-    LineAndColumn(int line = 0, int column = 0)
-        : line(line), column(column) {}
-};
-
 template<typename Container>
 struct ReversedContainer
 {

src/window.hh

@@ -3,7 +3,7 @@
 
 #include <functional>
 
-#include "utils.hh"
+#include "line_and_column.hh"
 
 #include "buffer.hh"
 #include "display_buffer.hh"
@@ -11,7 +11,7 @@
 namespace Kakoune
 {
 
-struct WindowCoord : LineAndColumn
+struct WindowCoord : LineAndColumn<WindowCoord>
 {
     WindowCoord(int line = 0, int column = 0)
         : LineAndColumn(line, column) {}