by amanelis on 6/26/12, 8:24 AM with 26 comments
by dasil003 on 6/26/12, 9:50 AM
All code has a cost, primitives have a lower base cost because they are universal in the language and thus every programmer will automatically know how to use them. Before introducing a custom object with yet another API to be learned, you need justification.
> Implement Money class if you need to deal with money, it’s much better than using floats all over the place. Don’t use Hash for configuration objects, use a custom Configuration class instead.
Let's pretend he said integer since floats for money is outright broken. Yes, Money is a clearcut case where having a money-specific API is both intuitive and immediately useful.
Configuration on the other hand is debatable. If you're just doing things a hash does then it's fine. If you find yourself with lots of helper methods or repeating the same transformations over and over then that's when you have a code smell that may warrant lifting configuration to its own level.
But the critical thing is to remember that there's a non-trivial cost to creating domain-specific objects.
by cageface on 6/26/12, 10:05 AM
Personally I'm on the fence but when you look at how much boilerplate this Virtus example needs to get rid of the code "smell" you have to wonder if maybe he has a point.
by praptak on 6/26/12, 9:32 AM
"The simple structure and natural applicability of lists are reflected in functions that are amazingly nonidiosyncratic. In Pascal the plethora of declarable data structures induces a specialization within functions that inhibits and penalizes casual cooperation. It is better to have 100 functions operate on one data structure than to have 10 functions operate on 10 data structures."
by danieldk on 6/26/12, 9:49 AM
So, IMO it depends on the language features available and the scenario whether it is a code smell. For instance, Haskell allows you to introduce a new type whose data representation is the same as the original type using newtype [1]. In contrast to a type alias, newtype makes a different type, but it still allows you to define functions on that type in terms of the original type (using the type's constructor). If you want to hide the underlying representation, you simply do not export the constructors from the enclosing module.
tl;dr: in Haskell you do get a better abstraction without the overhead. I am pretty sure many other language can do as well (private inheritance in C++?).
[1] http://www.haskell.org/onlinereport/decls.html#datatype-rena...
by lucaspiller on 6/26/12, 9:33 AM
If you return a Hash of attributes everyone knows how a Hash works, but if you return a custom Attributes object people have to learn how it works, there could be bugs, etc.
by awongh on 6/28/12, 8:24 AM
by localhost3000 on 6/26/12, 11:22 AM