How to implement to!T(JSONValue)?

[crimaniak via Digitalmars-d-learn]

Hi!
 I need to read bad-formed json files in type-tolerant mode, and 
my idea is to make JSONValue-specific 'to' method which will 
convert it to target type if applicable, else throw exception. 
Like this:

import std.json;

unittest
{
    JSONValue s="123";
    JSONValue i=123;
    JSONValue f=123.0f;
    JSONValue a=[1,2,3];

    float result;

    result = s.to!float;
    assert(result == 123.);

    result = i.to!float;
    assert(result == 123.);

    result = f.to!float;
    assert(result == 123.);

    result = a.to!float; /// <-- exception
}

Naive approach doesn't works:

T to(T)(JSONValue value)
{
        final switch(value.type)
        {
                case JSON_TYPE.ARRAY:
                        return value.array.to!T;
                case JSON_TYPE.FALSE:
                        return false.to!T;
                case JSON_TYPE.TRUE:
                        return true.to!T;
                case JSON_TYPE.FLOAT:
                        return value.floating.to!T;
                case JSON_TYPE.INTEGER:
                        return value.integer.to!T;
                case JSON_TYPE.NULL:
                        return null.to!T;
                case JSON_TYPE.OBJECT:
                        return value.object.to!T;
                case JSON_TYPE.STRING:
                        return value.string.to!T;
                case JSON_TYPE.UINTEGER:
                        return value.uinteger.to!T;
        }
}

So my questions: is this possible to avoid explicit writing all 
specializations for every combination of JSON_TYPE/T required? 
How to resolve this task in right way?