Use a QValueEnd type with jus the bool result to hide QValueStatus

undesirable methods like value() that allowed to concatenate QValues in,
say, a JSON stream

tests/QBind/QCbor_impl.h

@@ -465,7 +465,7 @@ private:
 
 template<>
 struct QTransmogrifier<QCborValue> {
-    static QValueStatus zap(QValue&& v, QCborValue&& j) {
+    static QValueEnd zap(QValue&& v, QCborValue&& j) {
         if (v->mode()==Write) {
             if (j.isMap      ()) return v.bind(j.toMap      ());
             if (j.isArray    ()) return v.bind(j.toArray    ());
@@ -480,7 +480,7 @@ struct QTransmogrifier<QCborValue> {
         }
         else { Q_ASSERT_X(false, Q_FUNC_INFO, "Unsupported v->mode()"); return v.any(); }
     }
-    static QValueStatus zap(QValue&& v, QCborValue& j) {
+    static QValueEnd zap(QValue&& v, QCborValue& j) {
         if (v->mode()==Write) {
             return zap(std::move(v),std::move(j));
         }
@@ -507,7 +507,7 @@ struct QTransmogrifier<QCborValue> {
 
 template<>
 struct QTransmogrifier<QCborArray> {
-    static QValueStatus zap(QValue&& v, QCborArray&& j) {
+    static QValueEnd zap(QValue&& v, QCborArray&& j) {
         if (v->mode()==Write) {
             quint32 size=quint32(j.size());
             auto s(v.sequence(&size));
@@ -518,7 +518,7 @@ struct QTransmogrifier<QCborArray> {
         }
         else { Q_ASSERT_X(false, Q_FUNC_INFO, "Unsupported v->mode()"); return v.any(); }
     }
-    static QValueStatus zap(QValue&& v, QCborArray& j) {
+    static QValueEnd zap(QValue&& v, QCborArray& j) {
         if (v->mode()==Write) {
             return zap(std::move(v),std::move(j));
         }
@@ -538,7 +538,7 @@ struct QTransmogrifier<QCborArray> {
 
 template<>
 struct QTransmogrifier<QCborMap> {
-    static QValueStatus zap(QValue&& v, QCborMap&& j) {
+    static QValueEnd zap(QValue&& v, QCborMap&& j) {
         if (v->mode()==Write) {
             quint32 size=quint32(j.size());
             auto r(v.record(&size));
@@ -553,7 +553,7 @@ struct QTransmogrifier<QCborMap> {
         }
         else { Q_ASSERT_X(false, Q_FUNC_INFO, "Unsupported v->mode()"); return v.any(); }
     }
-    static QValueStatus zap(QValue&& v, QCborMap& j) {
+    static QValueEnd zap(QValue&& v, QCborMap& j) {
         if (v->mode()==Write) {
             return zap(std::move(v),std::move(j));
         }

tests/QBind/QData_impl.h

@@ -65,7 +65,7 @@ public:
     QValue    value   (                  ) { return QValueStatus(this).value(); }
     QSequence sequence(quint32* s=nullptr) { return QValueStatus(this).value().sequence(s); }
 
-    template<typename T> QValueStatus zap(T&& t) { return QValueStatus(this).value().bind(std::forward<T>(t)); }
+    template<typename T> QValueEnd zap(T&& t) { return QValueStatus(this).value().bind(std::forward<T>(t)); }
 protected:
     friend class QValueStatus;
     bool trySequence(quint32* s=nullptr) { if (s) *io <<       *s; return true; }

tests/QBind/QJson_impl.h

@@ -240,7 +240,7 @@ public:
     }
 
     struct Step  { int index; const char* end; QMap<QIdentifier,QJsonValue/*TODO QVariant for meta() support*/> cachedItems; Step(int i=-1, const char* e=nullptr) : index(i), end(e) {} };
-    struct Error { QIdentifierLiteral error; int line; int column; int index; QValueStatus zap(QValue&& value) { QByteArray u(error.utf8()); u.append(' ').append(QByteArray::number(line)).append(':').append(QByteArray::number(column)); return value.bind(QUtf8Data(u)); } };
+    struct Error { QIdentifierLiteral error; int line; int column; int index; QValueEnd zap(QValue&& value) { QByteArray u(error.utf8()); u.append(' ').append(QByteArray::number(line)).append(':').append(QByteArray::number(column)); return value.bind(QUtf8Data(u)); } };
     QVector<Error> errors;
 
     // Shortcuts
@@ -523,7 +523,7 @@ private:
 
 template<>
 struct QTransmogrifier<QJsonValue> {
-    static QValueStatus zap(QValue&& v, QJsonValue&& j) {
+    static QValueEnd zap(QValue&& v, QJsonValue&& j) {
         if (v->mode()==Write) {
             if (j.isObject()) return v.bind(j.toObject());
             if (j.isArray ()) return v.bind(j.toArray ());
@@ -536,7 +536,7 @@ struct QTransmogrifier<QJsonValue> {
         }
         else { Q_ASSERT_X(false, Q_FUNC_INFO, "Unsupported v->mode()"); return v.any(); }
     }
-    static QValueStatus zap(QValue&& v, QJsonValue& j) {
+    static QValueEnd zap(QValue&& v, QJsonValue& j) {
         if (v->mode()==Write) {
             return zap(std::move(v),std::move(j));
         }
@@ -561,7 +561,7 @@ struct QTransmogrifier<QJsonValue> {
 
 template<>
 struct QTransmogrifier<QJsonArray> {
-    static QValueStatus zap(QValue&& v, QJsonArray&& j) {
+    static QValueEnd zap(QValue&& v, QJsonArray&& j) {
         if (v->mode()==Write) {
             quint32 size=quint32(j.size());
             auto s(v.sequence(&size));
@@ -572,7 +572,7 @@ struct QTransmogrifier<QJsonArray> {
         }
         else { Q_ASSERT_X(false, Q_FUNC_INFO, "Unsupported v->mode()"); return v.any(); }
     }
-    static QValueStatus zap(QValue&& v, QJsonArray& j) {
+    static QValueEnd zap(QValue&& v, QJsonArray& j) {
         if (v->mode()==Write) {
             return zap(std::move(v),std::move(j));
         }
@@ -592,7 +592,7 @@ struct QTransmogrifier<QJsonArray> {
 
 template<>
 struct QTransmogrifier<QJsonObject> {
-    static QValueStatus zap(QValue&& v, QJsonObject&& j) {
+    static QValueEnd zap(QValue&& v, QJsonObject&& j) {
         if (v->mode()==Write) {
             quint32 size=quint32(j.size());
             auto s(v.record(&size));
@@ -604,7 +604,7 @@ struct QTransmogrifier<QJsonObject> {
         }
         else { Q_ASSERT_X(false, Q_FUNC_INFO, "Unsupported v->mode()"); return v.any(); }
     }
-    static QValueStatus zap(QValue&& v, QJsonObject& j) {
+    static QValueEnd zap(QValue&& v, QJsonObject& j) {
         if (v->mode()==Write) {
             return zap(std::move(v),std::move(j));
         }

tests/QBind/README.md

@@ -99,7 +99,7 @@ struct Person
 {
     QString firstName, lastName; double height; int age; QVector<QString> phones; QString comments; QList<Person> children;
 
-    QValueStatus zap(QValue&& value) { // works with value->mode()==Read as well as Write
+    QValueEnd zap(QValue&& value) { // works with value->mode()==Read as well as Write
         return value
             .record("Person") // aggregates a usually small number of named items in any order (Person is an optional meta-name for the record that may be ignored)
                 .sequence("names") // aggregates any number of items in a fixed order, just to illustrate a basic mapping between struct Person and a more general data schema
@@ -247,8 +247,8 @@ Each specialization must implement at least the bind() method for lvalue referen
 references to support temporaries, and for const lvalue reference to efficiently support copyable types.
 ```cpp
 template<> struct QTransmogrifier<QColor> {
-    static QValueStatus zap(QValue&& v, QColor&& c) { QColor copy(c); return bind(std::move(v),copy); } // supports writing temporaries and const QColor&
-    static QValueStatus zap(QValue&& v, QColor&  c) {
+    static QValueEnd zap(QValue&& v, QColor&& c) { QColor copy(c); return bind(std::move(v),copy); } // supports writing temporaries and const QColor&
+    static QValueEnd zap(QValue&& v, QColor&  c) {
         if (!c.isValid()) {
             return v.null();
         }

tests/QBind/main.cpp

@@ -84,7 +84,7 @@ struct Person
 {
     int id; QString firstName, lastName; double height; int age; QVector<Phone> phones; QString comments; QList<Person> children;
 
-    QValueStatus zap(QValue&& value) { // works with value->mode()==Read as well as Write
+    QValueEnd zap(QValue&& value) { // works with value->mode()==Read as well as Write
         return value
             .record("Person")
                 .sequence("names")
@@ -137,7 +137,7 @@ struct PersonsView
 {
     QList<Person>& persons;
 
-    QValueStatus zap(QValue&& value) {
+    QValueEnd zap(QValue&& value) {
         return value
             .meta(qmChildren,"children")
             .meta(qmColumns ,"names,height,age,phones,comments") // to optimize multi-dimensional data formats
@@ -151,7 +151,7 @@ struct PersonsTable {
     QList<Person>& persons;
     PersonsTable(QList<Person>& ps) : persons(ps) {}
 
-    QValueStatus zap(QValue&& v) {
+    QValueEnd zap(QValue&& v) {
         if (v->mode()==Read) {
             ids.clear();
             orphans.clear();
@@ -254,11 +254,11 @@ private:
 //! QTransmogrifier<QColor> with special support for QDataStream compatibility using meta()
 template<>
 struct QTransmogrifier<QColor> {
-    static QValueStatus zap(QValue&& v, QColor&& c) {
+    static QValueEnd zap(QValue&& v, QColor&& c) {
         QColor copy(c);
         return zap(std::move(v),copy);
     }
-    static QValueStatus zap(QValue&& v, QColor& c) {
+    static QValueEnd zap(QValue&& v, QColor& c) {
         if (!c.isValid()) {
             return v.null();
         }