json confusion

[jjude]

I am writing an api sever in Nim. The output is of the form: 
    
    
    {
            code:"tk.01",
            message: "Token in data field",
            data:"12345"
    }
    
    
    
    Run

data field could be a string, single object (say a blog post), or an array 
(sequence) of objects (list of posts). I was successful in emitting the string 
without any trouble. But I want to make a generic object that I can use to hold 
these values around the application.
    
    
    type retVal = object
            code: string
            message: string
            data: ?
    
    
    Run

I don't know what datatype data should be.

Also I am trying to create a proc that can output a json to the outside world 
(not just withing Nim application). Everything I tried with json module outputs 
as string rather than json (like the above) for objects.

The following code prints json correctly, but I'm lost how to pass json in and 
out of procs.
    
    
    import marshal
    
    type
      Person = object
        age: int
        name: string
    
    var p = Person(age: 38, name: "Torbjørn")
    
    echo($$p)
    
    
    Run

Thanks