Disambiguate GenericValue's [0] and ["string"]

example/tutorial/tutorial.cpp

@@ -72,12 +72,8 @@ int main(int, char*[]) {
         for (SizeType i = 0; i < a.Size(); i++) // rapidjson uses SizeType instead of size_t.
             printf("a[%d] = %d\n", i, a[i].GetInt());
         
-        // Note:
-        //int x = a[0].GetInt();                    // Error: operator[ is ambiguous, as 0 also mean a null pointer of const char* type.
-        int y = a[SizeType(0)].GetInt();            // Cast to SizeType will work.
-        int z = a[0u].GetInt();                     // This works too.
+        int y = a[0].GetInt();
         (void)y;
-        (void)z;
 
         // Iterating array with iterators
         printf("a = ");

include/rapidjson/document.h

@@ -795,6 +795,15 @@ public:
     //! Check whether the object is empty.
     bool ObjectEmpty() const { RAPIDJSON_ASSERT(IsObject()); return data_.o.size == 0; }
 
+    template <typename T>
+    GenericValue& operator[](T t) {
+	    return DoIndex(t, internal::IsPointer<T>());
+    }
+
+    template <typename T>
+    const GenericValue& operator[](T t) const { return const_cast<GenericValue&>(*this)[t]; }
+
+private:
     //! Get the value associated with the name.
     /*!
         \note In version 0.1x, if the member is not found, this function returns a null value. This makes issue 7.
@@ -803,12 +812,22 @@ public:
         A better approach is to use FindMember().
         \note Linear time complexity.
     */
-    GenericValue& operator[](const Ch* name) {
+
+    GenericValue& DoIndex(const Ch* name, internal::TrueType) {
         GenericValue n(StringRef(name));
         return (*this)[n];
     }
-    const GenericValue& operator[](const Ch* name) const { return const_cast<GenericValue&>(*this)[name]; }
 
+    //! Get an element from array by index.
+    /*! \param index Zero-based index of element.
+    */
+    GenericValue& DoIndex(SizeType index, internal::FalseType) {
+        RAPIDJSON_ASSERT(IsArray());
+        RAPIDJSON_ASSERT(index < data_.a.size);
+        return data_.a.elements[index];
+    }
+
+public:
     // This version is faster because it does not need a StrLen(). 
     // It can also handle string with null character.
     template <typename SourceAllocator>
@@ -1131,23 +1150,6 @@ public:
         data_.a.size = 0;
     }
 
-    //! Get an element from array by index.
-    /*! \param index Zero-based index of element.
-\code
-Value a(kArrayType);
-a.PushBack(123);
-int x = a[0].GetInt();              // Error: operator[ is ambiguous, as 0 also mean a null pointer of const char* type.
-int y = a[SizeType(0)].GetInt();    // Cast to SizeType will work.
-int z = a[0u].GetInt();             // This works too.
-\endcode
-    */
-    GenericValue& operator[](SizeType index) {
-        RAPIDJSON_ASSERT(IsArray());
-        RAPIDJSON_ASSERT(index < data_.a.size);
-        return data_.a.elements[index];
-    }
-    const GenericValue& operator[](SizeType index) const { return const_cast<GenericValue&>(*this)[index]; }
-
     //! Element iterator
     /*! \pre IsArray() == true */
     ValueIterator Begin() { RAPIDJSON_ASSERT(IsArray()); return data_.a.elements; }

test/unittest/documenttest.cpp

@@ -218,7 +218,7 @@ TEST(Document, UTF16_Document) {
     json.Parse<kParseValidateEncodingFlag>(L"[{\"created_at\":\"Wed Oct 30 17:13:20 +0000 2012\"}]");
 
     ASSERT_TRUE(json.IsArray());
-    GenericValue< UTF16<> >& v = json[0u];
+    GenericValue< UTF16<> >& v = json[0];
     ASSERT_TRUE(v.IsObject());
 
     GenericValue< UTF16<> >& s = v[L"created_at"];

test/unittest/valuetest.cpp

@@ -672,17 +672,17 @@ TEST(Value, Array) {
     EXPECT_FALSE(y.Empty());
     EXPECT_EQ(5u, y.Size());
     EXPECT_TRUE(x[SizeType(0)].IsNull());
-    EXPECT_TRUE(x[1u].IsTrue());
-    EXPECT_TRUE(x[2u].IsFalse());
-    EXPECT_TRUE(x[3u].IsInt());
-    EXPECT_EQ(123, x[3u].GetInt());
+    EXPECT_TRUE(x[1].IsTrue());
+    EXPECT_TRUE(x[2].IsFalse());
+    EXPECT_TRUE(x[3].IsInt());
+    EXPECT_EQ(123, x[3].GetInt());
     EXPECT_TRUE(y[SizeType(0)].IsNull());
-    EXPECT_TRUE(y[1u].IsTrue());
-    EXPECT_TRUE(y[2u].IsFalse());
-    EXPECT_TRUE(y[3u].IsInt());
-    EXPECT_EQ(123, y[3u].GetInt());
-    EXPECT_TRUE(y[4u].IsString());
-    EXPECT_STREQ("foo", y[4u].GetString());
+    EXPECT_TRUE(y[1].IsTrue());
+    EXPECT_TRUE(y[2].IsFalse());
+    EXPECT_TRUE(y[3].IsInt());
+    EXPECT_EQ(123, y[3].GetInt());
+    EXPECT_TRUE(y[4].IsString());
+    EXPECT_STREQ("foo", y[4].GetString());
 
 #if RAPIDJSON_HAS_CXX11_RVALUE_REFS
     // PushBack(GenericValue&&, Allocator&);
@@ -691,11 +691,11 @@ TEST(Value, Array) {
         y.PushBack(Value(true), allocator);
         y.PushBack(std::move(Value(kArrayType).PushBack(Value(1), allocator).PushBack("foo", allocator)), allocator);
         EXPECT_EQ(2u, y.Size());
-        EXPECT_TRUE(y[0u].IsTrue());
-        EXPECT_TRUE(y[1u].IsArray());
-        EXPECT_EQ(2u, y[1u].Size());
-        EXPECT_TRUE(y[1u][0u].IsInt());
-        EXPECT_TRUE(y[1u][1u].IsString());
+        EXPECT_TRUE(y[0].IsTrue());
+        EXPECT_TRUE(y[1].IsArray());
+        EXPECT_EQ(2u, y[1].Size());
+        EXPECT_TRUE(y[1][0].IsInt());
+        EXPECT_TRUE(y[1][1].IsString());
     }
 #endif
 
@@ -741,9 +741,9 @@ TEST(Value, Array) {
     x.PopBack();
     EXPECT_EQ(4u, x.Size());
     EXPECT_TRUE(y[SizeType(0)].IsNull());
-    EXPECT_TRUE(y[1u].IsTrue());
-    EXPECT_TRUE(y[2u].IsFalse());
-    EXPECT_TRUE(y[3u].IsInt());
+    EXPECT_TRUE(y[1].IsTrue());
+    EXPECT_TRUE(y[2].IsFalse());
+    EXPECT_TRUE(y[3].IsInt());
 
     // Clear()
     x.Clear();
@@ -764,23 +764,23 @@ TEST(Value, Array) {
     EXPECT_EQ(x.Begin(), itr);
     EXPECT_EQ(9u, x.Size());
     for (int i = 0; i < 9; i++)
-        EXPECT_EQ(i + 1, x[i][0u].GetInt());
+        EXPECT_EQ(i + 1, x[i][0].GetInt());
 
     // Ease the last
     itr = x.Erase(x.End() - 1);
     EXPECT_EQ(x.End(), itr);
     EXPECT_EQ(8u, x.Size());
     for (int i = 0; i < 8; i++)
-        EXPECT_EQ(i + 1, x[i][0u].GetInt());
+        EXPECT_EQ(i + 1, x[i][0].GetInt());
 
     // Erase the middle
     itr = x.Erase(x.Begin() + 4);
     EXPECT_EQ(x.Begin() + 4, itr);
     EXPECT_EQ(7u, x.Size());
     for (int i = 0; i < 4; i++)
-        EXPECT_EQ(i + 1, x[i][0u].GetInt());
+        EXPECT_EQ(i + 1, x[i][0].GetInt());
     for (int i = 4; i < 7; i++)
-        EXPECT_EQ(i + 2, x[i][0u].GetInt());
+        EXPECT_EQ(i + 2, x[i][0].GetInt());
 
     // Erase(ValueIterator, ValueIterator)
     // Exhaustive test with all 0 <= first < n, first <= last <= n cases
@@ -800,9 +800,9 @@ TEST(Value, Array) {
             size_t removeCount = last - first;
             EXPECT_EQ(n - removeCount, x.Size());
             for (unsigned i = 0; i < first; i++)
-                EXPECT_EQ(i, x[i][0u].GetUint());
+                EXPECT_EQ(i, x[i][0].GetUint());
             for (unsigned i = first; i < n - removeCount; i++)
-                EXPECT_EQ(i + removeCount, x[i][0u].GetUint());
+                EXPECT_EQ(i + removeCount, x[i][0].GetUint());
         }
     }
 
@@ -1012,7 +1012,7 @@ TEST(Value, Object) {
     for (; itr != x.MemberEnd(); ++itr) {
         int i = (itr - x.MemberBegin()) + 1;
         EXPECT_STREQ(itr->name.GetString(), keys[i]);
-        EXPECT_EQ(i, itr->value[0u].GetInt());
+        EXPECT_EQ(i, itr->value[0].GetInt());
     }
 
     // Erase the last
@@ -1023,7 +1023,7 @@ TEST(Value, Object) {
     for (; itr != x.MemberEnd(); ++itr) {
         int i = (itr - x.MemberBegin()) + 1;
         EXPECT_STREQ(itr->name.GetString(), keys[i]);
-        EXPECT_EQ(i, itr->value[0u].GetInt());
+        EXPECT_EQ(i, itr->value[0].GetInt());
     }
 
     // Erase the middle
@@ -1035,7 +1035,7 @@ TEST(Value, Object) {
         int i = (itr - x.MemberBegin());
         i += (i<4) ? 1 : 2;
         EXPECT_STREQ(itr->name.GetString(), keys[i]);
-        EXPECT_EQ(i, itr->value[0u].GetInt());
+        EXPECT_EQ(i, itr->value[0].GetInt());
     }
 
     // EraseMember(ConstMemberIterator, ConstMemberIterator)
@@ -1056,9 +1056,9 @@ TEST(Value, Object) {
             size_t removeCount = last - first;
             EXPECT_EQ(n - removeCount, x.MemberCount());
             for (unsigned i = 0; i < first; i++)
-                EXPECT_EQ(i, x[keys[i]][0u].GetUint());
+                EXPECT_EQ(i, x[keys[i]][0].GetUint());
             for (unsigned i = first; i < n - removeCount; i++)
-                EXPECT_EQ(i + removeCount, x[keys[i+removeCount]][0u].GetUint());
+                EXPECT_EQ(i + removeCount, x[keys[i+removeCount]][0].GetUint());
         }
     }