add array element proxy support

diff --git a/janssonxx.h b/janssonxx.h
index 935ac9e..193a354 100644 (file)
--- a/janssonxx.h
+++ b/janssonxx.h
@@ -21,6 +21,7 @@ namespace jansson {
 
        class Iterator;
        class Value;
+       class _ArrayProxy;
 
        // base class for JSON value interface
        template <typename _Base>
@@ -35,6 +36,9 @@ namespace jansson {
                // create reference to value
                _ValueBase(json_t* json) : _Base(json) {}
 
+               // assignment operator
+               _ValueBase& operator=(const Value& value) { _Base::operator=(value); return *this; }
+
                // check value type
                bool is_undefined() const { return _Base::as_json() == 0; }
                bool is_object() const { return json_is_object(_Base::as_json()); }
@@ -62,14 +66,14 @@ namespace jansson {
                inline const Value operator[](unsigned long index) const;
 
                // get value at array index (non-const version)
-               inline Value at(unsigned int index);
+               inline _ValueBase<_ArrayProxy> at(unsigned int index);
 
-               inline Value operator[](signed int index);
-               inline Value operator[](unsigned int index);
-               inline Value operator[](signed short index);
-               inline Value operator[](unsigned short index);
-               inline Value operator[](signed long index);
-               inline Value operator[](unsigned long index);
+               inline _ValueBase<_ArrayProxy> operator[](signed int index);
+               inline _ValueBase<_ArrayProxy> operator[](unsigned int index);
+               inline _ValueBase<_ArrayProxy> operator[](signed short index);
+               inline _ValueBase<_ArrayProxy> operator[](unsigned short index);
+               inline _ValueBase<_ArrayProxy> operator[](signed long index);
+               inline _ValueBase<_ArrayProxy> operator[](unsigned long index);
 
                // get object property
                inline const Value get(const char* key) const;
@@ -149,6 +153,29 @@ namespace jansson {
                json_t* _value;
        };
 
+       // proxies an array element
+       class _ArrayProxy {
+       public:
+               // construct new Value with an undefined value
+               _ArrayProxy() : _array(0), _index(0) {}
+
+               // constructor
+               _ArrayProxy(json_t* array, unsigned int index) : _array(array), _index(index) {}
+
+               // assign to the proxied element
+               inline _ArrayProxy& operator=(const Value& value);
+
+               // get the proxied element
+               json_t* as_json() const { return json_array_get(_array, _index); }
+
+       private:
+               // array object we wrap
+               json_t* _array;
+
+               // index of property
+               unsigned int _index;
+       };
+
        // represents any JSON value
        class Value : public _ValueBase<_Value> {
        public:

diff --git a/janssonxx.tcc b/janssonxx.tcc
index 2b5c8aa..c4b1efa 100644 (file)
--- a/janssonxx.tcc
+++ b/janssonxx.tcc
@@ -28,22 +28,22 @@ const jansson::Value jansson::_ValueBase<_Base>::operator[](unsigned long index)
 
 // get value at array index (non-const version)
 template <typename _Base>
-jansson::Value jansson::_ValueBase<_Base>::at(unsigned int index) {
-       return jansson::Value(json_array_get(_Base::as_json(), index));
+jansson::_ValueBase<jansson::_ArrayProxy> jansson::_ValueBase<_Base>::at(unsigned int index) {
+       return _ArrayProxy(_Base::as_json(), index);
 }
 
 template <typename _Base>
-jansson::Value jansson::_ValueBase<_Base>::operator[](signed int index) { return at(index); }
+jansson::_ValueBase<jansson::_ArrayProxy> jansson::_ValueBase<_Base>::operator[](signed int index) { return at(index); }
 template <typename _Base>
-jansson::Value jansson::_ValueBase<_Base>::operator[](unsigned int index) { return at(index); }
+jansson::_ValueBase<jansson::_ArrayProxy> jansson::_ValueBase<_Base>::operator[](unsigned int index) { return at(index); }
 template <typename _Base>
-jansson::Value jansson::_ValueBase<_Base>::operator[](signed short index) { return at(index); }
+jansson::_ValueBase<jansson::_ArrayProxy> jansson::_ValueBase<_Base>::operator[](signed short index) { return at(index); }
 template <typename _Base>
-jansson::Value jansson::_ValueBase<_Base>::operator[](unsigned short index) { return at(index); }
+jansson::_ValueBase<jansson::_ArrayProxy> jansson::_ValueBase<_Base>::operator[](unsigned short index) { return at(index); }
 template <typename _Base>
-jansson::Value jansson::_ValueBase<_Base>::operator[](signed long index) { return at(index); }
+jansson::_ValueBase<jansson::_ArrayProxy> jansson::_ValueBase<_Base>::operator[](signed long index) { return at(index); }
 template <typename _Base>
-jansson::Value jansson::_ValueBase<_Base>::operator[](unsigned long index) { return at(index); }
+jansson::_ValueBase<jansson::_ArrayProxy> jansson::_ValueBase<_Base>::operator[](unsigned long index) { return at(index); }
 
 // get object property
 template <typename _Base>
@@ -131,3 +131,9 @@ template <typename _Base>
        json_array_insert(_Base::as_json(), index, value._Base::as_json());
        return *this;
 }
+
+// assign value to proxied array element
+jansson::_ArrayProxy& jansson::_ArrayProxy::operator=(const Value& value) {
+       json_array_set(_array, _index, value.as_json());
+       return *this;
+}

diff --git a/test.cc b/test.cc
index fb66f63..bff3cef 100644 (file)
--- a/test.cc
+++ b/test.cc
@@ -149,7 +149,13 @@ int main() {
        e14.set_key("foo", jansson::Value::object());
        ASSERT_TRUE(e14["foo"].is_object(), "e14.foo is not an object after assignment");
        //e14["foo"]["bar"] = jansson::Value::from(42);
-       //ASSERT_EQ(e14["foo"]["bar"].as_integer(), 42, "e14.foo.bar has incorrecy value after assignment");
-
+       //ASSERT_EQ(e14["foo"]["bar"].as_integer(), 42, "e14.foo.bar has incorrect value after assignment");
+
+       jansson::Value e15(jansson::Value::array());
+       ASSERT_TRUE(e15.is_array(), "e15 is not an array after construction");
+       e15.set_at(0, jansson::Value::from(42));
+       ASSERT_EQ(e15[0].as_integer(), 42, "e15[0] has incorrect value after assignment");
+       e15[0] = jansson::Value::from("foo");
+       ASSERT_EQ(e15[0].as_string(), "foo", "e15[0] has incorrecy value after assignment");
        return 0;
 }