CRTP

Author: tbaederr

clang/lib/Frontend/TextDiagnostic.cpp

@@ -47,40 +47,39 @@ static constexpr raw_ostream::Colors CommentColor = raw_ostream::YELLOW;
 static constexpr raw_ostream::Colors LiteralColor = raw_ostream::GREEN;
 static constexpr raw_ostream::Colors KeywordColor = raw_ostream::BLUE;
 
-class ColumnsOrBytes {
+template <typename Sub> class ColumnsOrBytes {
 public:
   int V = 0;
   ColumnsOrBytes(int V) : V(V) {}
   bool isValid() const { return V != -1; }
+  Sub next() const { return Sub(V + 1); }
+  Sub prev() const { return Sub(V - 1); }
 
-  bool operator>(ColumnsOrBytes O) { return V > O.V; }
-  bool operator<(ColumnsOrBytes O) { return V < O.V; }
-  bool operator<=(ColumnsOrBytes B) { return V <= B.V; }
-  bool operator!=(ColumnsOrBytes C) { return C.V != V; }
+  bool operator>(ColumnsOrBytes O) const { return V > O.V; }
+  bool operator<(ColumnsOrBytes O) const { return V < O.V; }
+  bool operator<=(ColumnsOrBytes B) const { return V <= B.V; }
+  bool operator!=(ColumnsOrBytes C) const { return C.V != V; }
 
-  ColumnsOrBytes &operator+=(ColumnsOrBytes B) {
+  Sub operator+(Sub B) const { return Sub(V + B.V); }
+  Sub &operator+=(Sub B) {
     V += B.V;
-    return *this;
+    return *(Sub *)this;
   }
-  ColumnsOrBytes &operator-=(ColumnsOrBytes B) {
+  Sub operator-(Sub B) const { return Sub{V - B.V}; }
+  Sub &operator-=(Sub B) {
     V -= B.V;
-    return *this;
+    return *(Sub *)this;
   }
 };
-class Bytes final : public ColumnsOrBytes {
+
+class Bytes final : public ColumnsOrBytes<Bytes> {
 public:
   Bytes(int V) : ColumnsOrBytes(V) {}
-  Bytes next() const { return Bytes(V + 1); }
-  Bytes prev() const { return Bytes(V - 1); }
-  Bytes operator+(Bytes B) { return Bytes{V + B.V}; }
 };
-class Columns final : public ColumnsOrBytes {
+
+class Columns final : public ColumnsOrBytes<Columns> {
 public:
   Columns(int V) : ColumnsOrBytes(V) {}
-  Columns next() const { return Columns(V + 1); }
-  Columns prev() const { return Columns(V - 1); }
-  Columns operator-(Columns B) { return Columns{V - B.V}; }
-  Columns operator+(Columns B) { return Columns{V + B.V}; }
 };
 
 /// Add highlights to differences in template strings.