Re: Nested immutable value objects

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 <[email protected]> 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
>
>  
>