Why do all examples clone() and move all values into callbacks?

[tobia]

I noticed that all examples clone() and move all values into the callbacks, including the ui context and all controls. In the case of inptus.rs, the mutable application state is wrapped in a Rc (over the RefCell) to be able to clone() and move several references into the callbacks.

I tried removing all of this overhead, just passing around simple read-only references, and everything seems to work the same (on Linux.)

What is the reason for adding those operations to the examples? Could you add a paragraph of documentation to the README explaining this choice?

In case it is needed to avoid problems and/or cross-platform compatibility, could you make it so that forgetting to do it would cause a compilation error? It seems an easy thing to forget, especially since everything seems to be working the same.

[NoraCodes]

Hi, thanks for pointing this out. It's a symptom of old bad api design and it should go away, since the api is now fixed.

[tobia]

Ok thank you.

While we are on the topic of clone(), I see that the layout methods such as append() still take a direct moved value child: T, so in these calls one is still supposed to clone() the children to be added?

[tobia]

There's still much I don't understand. I successfully removed all clone() and move from the callbacks in inputs.rs, except for the one in on_tick(), which gives a lifetime error if I try to get rid of move.

Then I tried removing the Rc wrapper, leaving only the RefCell, and I get a result I don't understand. The code compiles and runs without errors, but the various callbacks seem to access different copies of the state object! I don't understand where those copies come from!