Reporting a minor pain point I had when working with Sealed Types recently

[David Alayachew]

Definitely agreed, ty for the response.

On Tue, Nov 7, 2023 at 10:33 AM Brian Goetz <brian.goetz at oracle.com> wrote:

> Local sealed classes live on that list of features that are reasonable to
> do, but always seem to have less leverage than other features we could work
> on.  We've gone through a few rounds of removing unnecessarily nesting
> restrictions (e.g., local records, allowing statics in inner classes), but
> there is always more to do.  Local sealed classes is one of these.  (Local
> methods is another.)
>
> As you've observed, the workaround is obvious; move it to an outer level
> of nesting, or into a local class.
>
> On 11/7/2023 10:10 AM, David Alayachew wrote:
>
> Hello Amber Dev Team,
>
> I have been making extremely frequent use of sealed types and records to
> model Abstract Data Types, but the lack of local sealed types is becoming
> more and more of an annoyance to me.
>
> Annoyance is the correct word -- the cost I pay is in wasting time
> refactoring things. On rare occasions, I will refactor incorrectly and have
> to spend about 15-30 minutes reteaching myself what each one meant. This is
> certainly not an expensive cost. But this past week, I hit this problem
> multiple times back to back, such that the sum total was a few hours of
> refactoring across a full week of work. Because of that, this email felt
> warranted.
>
> To very quickly explain my situation, I have a bunch of projects I'm
> working on, each of which does a lot of work deserializing semi-structured
> outside data. So, an ideal use case for ADT's. I keep running into the same
> bar over and over again -- a project has many different types of data it
> needs to deserialize (>20 different data types), and several of those data
> types are quite similar to each other, such that the names end up being
> similar. When I go to refactor a class - either splitting it up or
> combining multiple classes into a single one, I usually end up either
> mixing up sealed types (using the incorrect one) or combining parent
> classes that both have private sealed types with the same name.
>
> This week was notable because almost all of my projects that I am working
> on ran into this same problem at around the same time.
>
> It's not a very big issue, but out of the 60+ hours I worked this week,
> I'd say about 3-4 of those hours were spent debugging and wasting time on
> fixing refactoring bugs. Admittedly, that's probably the worst-case
> scenario one can get for this problem, which shows that the scale of damage
> isn't very large. Also, I am pretty sure I know the reasons why it hasn't
> been done yet, and I don't contest them. However, I do want to share my
> experience in case that information influences any decision-making on the
> matter.
>
> Thank you for your time!
> David Alayachew
>
>
>
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