Re: Re: Nested immutable value objects

A model for cars will be definitively different depending of what is
managed. For instance, a tyre manufacturer may want to monitor the use of
instances of cars and tyres in order to improve its models.
Remy.

On 19 March 2013 15:27, sudarshan89 <[email protected]> wrote:

> **
>
>
> So does the Car class something like a copy constructor , where we give
> all the old values of the car , along with a new value for Fuel .. while
> constructing this new Car ?
>
> If we run with this Example of Car with 4 tires and Fuel ... Can you show
> me how you're Car, Fuel and Tyre classes would look ?
>
> --- In [email protected], Giacomo Tesio <giacomo@...>
> wrote:
> >
> > In C# I used delegate functions.
> >
> > Something like car.WithFluel(fluel => fluel.Increase(100)), with
> > Car.WithFluel() returning a new Car, and Fluel.Increase returning a new
> > Fluel. Car.WithFluel is responsible to mix the variation in the values.
> >
> > This works well as far as you don't have many levels of nested value
> > objects: on the real world examples that I've met till now, I've needed
> at
> > most 3 levels, and no one encountered problems while reading the code.
> Just
> > remember to document all exceptions that each method does not handle (see
> >
> http://epic.tesio.it/2013/03/04/exceptions-are-terms-ot-the-ubiquitous-language.html
> > ).
> >
> >
> > Giacomo
> >
> > On Tue, Mar 19, 2013 at 7:19 AM, sudarshan89 <sudarshan89@...> wrote:
> >
> > > **
> > >
> > >
> > > am trying to wrap my head around modelling with immutable objects,
> while
> > > doing so I am trying to understand how one would "update" a nested
> > > immutable object.
> > >
> > > I will just present my case with a help of an example, A car is filling
> > > fuel, this could be realized in code by creating a new car instance
> with a
> > > added fuel (keeping the immutable objects in mind, i do not just want
> to
> > > increment a counter) .
> > >
> > > So each time fuel is added I get a new car which has all the
> properties of
> > > the old car but the fuel tank has more fuel.
> > >
> > > This sounds conceptually good however we I try to code it down. My car
> > > would have a engine, tires and other immutable components, when a new
> car
> > > is created the entire graph needs to re created and then put into this
> new
> > > car, this would mean that i would need some kind of a copy constructor
> > > within my car class.
> > >
> > > I was curious to know how such a case can be handled cleanly ...
> > >
> > > Thanks
> > >
> > >
> > >
> >
>
>  
>