[swift-evolution] continuations - "extensions on steroids" idea

[Mike Kluev]

On 8 November 2017 at 10:54, Benjamin G <benjamin.garrigues at gmail.com>
wrote:

> All your use cases make perfect sense, however i see one potential issue
> with this "pattern" :
>
> I've seen a LOT of iOS developers (some juniors, some not) ending up with
> monstruous UIViewControllers, and it has happened almost since the very
> beginning of iOS development. Because of their lack of understanding of the
> MVC pattern, they completely under estimate either the model or the view
> layer and put too many things in their VC.
>
> Now this pattern would give them the illusion that they're working in a
> sane architecture and that they've decomposed the problem correctly, but in
> fact were not. The fact that extension wouldn't let you add variable makes
> it harder to conceal the problem, but with "continuations" i can see no
> limit.
>
> What do you think ?
>
>
good tools won't fix bad developers (c)

you know that you can already sort of "store variables" in extensions,
right? obj-c associated object is one way (1). and if we are talking about
the use case of extending "your own types only" -- i am -- your own classes
are under your full control, so nobody stops you from having, say, an
"extensionVars" dictionary in your root class(es) and a handy set of
generic api's to get/set those in a convenient manner without too much
effort (2). is it ideal? no. performance suffers. usability suffers. non
trivial to have weak/unowned variables with (2). not a "first class
citizen" solution. the sheer number of hits of "how to i store variables in
extensions in swift" (more than a million now) hints you that the language
can step in to help, at least in the critical use case of "own types".

Mike
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