Concept for a JDoc implementation that is fluent and well-typed.

JDoc

// ----------
// Definition
// ----------

class JDoc {
    
    //--- Types ---
    class ArrayBuilder<TOuter> {
        
        //--- Methods ---
        ArrayBuilder<TOuter> Null();
        ArrayBuilder<TOuter> Value(bool value);
        ArrayBuilder<TOuter> Value(string value);
        ArrayBuilder<TOuter> Value(int value);
        ArrayBuilder<TOuter> Value(double value);
        ArrayBuilder<ArrayBuilder<TOuter>> Array();
        ObjectBuilder<ArrayBuilder<TOuter>> Object();
        TOuter End();
    }
    
    class ObjectBuilder<TOuter> {

        //--- Methods ---
        ObjectKeyBuilder<TOuter> Key(string);
        TOuter End();
    }
    
    class ObjectKeyBuilder<TOuter> {
        
        //--- Methods ---
        ObjectBuilder<TOuter> Null();
        ObjectBuilder<TOuter> Value(bool value);
        ObjectBuilder<TOuter> Value(string value);
        ObjectBuilder<TOuter> Value(int value);
        ObjectBuilder<TOuter> Value(double value);
        ArrayBuilder<Object<TOuter>> Array();
        ObjectBuilder<ObjectBuilder<TOuter>> Object();
    }
    
    //--- Class Methods ---
    static JDoc Null();
    static JDoc Value(bool value);
    static JDoc Value(string value);
    static JDoc Value(int value);
    static JDoc Value(double value);
    static ArrayBuilder<JDoc> Array();
    static ObjectBuilder<JDoc> Object();
    
    //--- Methods ---
    // TBD
}


// --------
// Examples
// --------


// { "a": 123, "b": true, "c": [123.456, "hi"], "d": { "e": null }}
JDoc.Object()
    .Key("a").Value(123)
    .Key("b").Value(true)
    .Key("c").Array()
        .Value(123.456)
        .Value("hi")
    .End()
    .Key("d").Object()
        .Key("e").Null()
    .End()
.End();

// { }
JDco.Object().End();

// [123, "hi"]
JDoc.Array().Value(123).Value("hi").End();

// [ ]
JDoc.Array().End();

// 123
JDoc.Value(123);

// null
JDoc.Null();