3.6 KiB
service-pattern
- tags
- programming
- source
The question about code structure and organization is one of the most prolific one. The problem are always the same.
Here I will talk about one possible solution in this huge design space. First of all, I will focus on a functional programming pattern. But I think the lessons could be extended to any generic programming language.
Before explaining the pattern I would like to take the time to provide a few distinctions between different programming language patterns. Quite often, one fundamental question very important when choosing a pattern for your code is about find the the correct level of the pattern.
There are a tower of patterns and meta-patterns.
For example in imperative programming not using goto statement was
considered as a programming pattern.
Once that idea was accepted there were work done on Object Oriented
Programming.
And OOP was considered as a programming language pattern.
But OOP while already providing quite a constraint on your code
architecture was enough not sufficient.
OOP alone leave a lot of room in the design space.
Thus we've seen numerous "OOP Design Pattern".
That used the underlying OOP paradigm as a base and constructed
abstractions over it.
Even with all those Design Pattern it was up to the programmer to decide which one applies or not. Quite often there is not a single path easy to detect correct design pattern. Mainly the very hard part in programming is choosing the right abstraction.
There are other code structures to choose from. In functional programming there are FRP. Here also there are stories about how design pattern once choosen make a natural evolution toward meta-design-patterns. Mainly design pattern that rely on a lower level design pattern.
If you take the story behind Elm Architecture you can see it. At first there were FRP. Elm removed the behaviour from FRP to only deal with events to simplify the model. But with FRP the author clearly though it was a good-enough design pattern. But the design space was a bit too big. So it was difficult to take the right decision. So a natural meta-pattern appeared. It is Elm Architecture. So while Elm imposed so structure of your program using static types to prevent common coding mistakes and enforce a specific code structure. Elm did not constrain the file organisation, the number of buffers to send/receive events, the way they should talk/listen between each other.
So Elm Architecture is a non enforced meta structure for your code application. Unlike the underlying layer of architecture. But what Elm Architecture provide is a higher level architecture that will help your program to "scale" and whose natural organisation is easy to understand.
So Elm Architecture is more of a proposal that will potentially have drawback. Typically, if you change the organisation of your views, it could cost a lot of change in your code. But most of the time this is acceptable and preferable. Because, the Elm Architecture is simple to understand and quite often this is not such a big deal. Not using the Elm Architecture paradigm put you at risk to end up in a spaghetti code hell. But of course there is a tension between code size/DRYness and easy to understand code organisation/architecture.
If you have a short code base, DRYness could probably be preferable. Because a bit of disorganisation and shortcuts will not be unbearable. But as the size of your code grow, it will become more and more prevalent that a strict code organisation with perhaps more repetitions and a bit more