Yes, they return Unit, but the Compose annotation ...

# compose

[streetsofboston]

Yes, they return Unit, but the Compose annotation is hooked up to a compiler plugin and this causes some magic in generating a model/hierarchy of the views (that is what I understood from my unit-testing question here: https://kotlinlang.slack.com/archives/CJLTWPH7S/p1557666472013700?thread_ts=1557666472.013700&cid=CJLTWPH7S )

[miha-x64]

soooooo crappy creepy

[mbonnin]

"Any sufficiently advanced technology is indistinguishable from magic"

[miha-x64]

Any codegen and reflection is indistinguishable from legacy-code.

[mbonnin]

I believe that codegen and more intelligent compilers can actually make programming less repetitive. Reflection is mostly bad as it breaks compile time type safety.

[miha-x64]

Programming can be less repetitive without reflection/codegen. But this requires more intelligent programmers...

[mbonnin]

It's just a matter of what tools programmers learn. If you learn @JsonClass(generateAdapter = true), you will never need to know how to write a custom json serializer. Maybe it's a bad thing, maybe not. But then who knows how to write assembly these days...

[miha-x64]

https://www.joelonsoftware.com/2002/11/11/the-law-of-leaky-abstractions/

[streetsofboston]

But I thank all gods in heaven for abstractions and i’m willing to call a plumber or deal with the occasional leaks myself on occasion …. 🙂
I can’t imagine drawing all pixels myself, making sure that ordering UDP packages are in order and reliable (most of the time), dealing with garbage collection, etc. I think a lot of abstractions are good trade-offs (and some are not)

[napperley]

Is the use of annotations in Compose a good trade off considering there is a lot of magic involved with them (also increases build time)? Were other methods explored which don't require the use of annotations/meta-programming?

[miha-x64]

Of course it is a bad trade-off. Of course there are other methods.

[Ryan Mentley]

The annotation is just a signal to the compiler. Compose isn't an annotation processor, so you won't have the drawbacks you're used to with annotation processors.

[mbonnin]

@Ryan Mentley I'm curious why it doesn't use a keyword (like suspend for coroutines) by the way. That would hint at compiler support more. Or maybe plugins cannot add keywords ?

[Ryan Mentley]

@mbonnin You're exactly correct - plugins cannot add keywords. There's some discussion toward the end of this thread between Leland and Roman: https://kotlinlang.slack.com/archives/CJLTWPH7S/p1558440714121300