Create new `:event` type and related handlers/emitters as built-in functions?

[drkameleon]

See also:

https://discord.com/channels/765519132186640445/829324913097048065/1084769083771330632

[RickBarretto]

About this new type, how does should it work?

[drkameleon]

Well, the truth is this is something that remains to be studied.

A few thoughts...

• we could have 2 different functions, one for handling events (on) and one for emitting/triggering events (emit).
• there could be system-defined events (e.g. Nim clearly supports adding a hook for Ctrl+C events -> https://nim-lang.github.io/Nim/system.html#setControlCHook%2Cproc%29), which we could properly handle if necessary
• the user may also create different event on his own
• all of this would have to comply to a new :event type
• each event could also carry some data (perhaps any valid Arturo value encapsulated)

A rough example of what I'm talking about:

on 'ctrlC [e][
    print ["Received control-c event:" e]
]

or...

setNum: function [x,val][
     previousVal: var'x
     let x val
     emit.with:#[
           previous: previousVal
           current: var'x
     ] 'numberChanged 
]

on 'numberChanged [e][
     print "Number changed!"
     print ["previous value:" e\data\previousVal "current value:" e\data\currentVal]
]

a: 2
setNum 'a 3 
print a ; a has become 3, and the event has been triggered in the background

That's a very rough sketch, but this is pretty much what I've had in mind 😉

---

The whole idea is very, very similar to that of functions; and that's a reason why I haven't implemented it yet. Now, that being said, the Ctrl-C idea for example is something that could be used with events (but obviously not with functions, as they are in Arturo), given that the "emitter" is the system itself.

[RickBarretto]

Thanks for the explanation, I liked this idea!

[drkameleon]

Thanks for the explanation, I liked this idea!

Let's see... This needs some careful thought before!

For now, I would prefer it if we focused on existing issues & testing rather than adding something totally new, since - as it happens - with new features come new bugs. But it's definitely in my to-do list!

[RickBarretto]

For now, I would prefer it if we focused on existing issues & testing rather than adding something totally new, 

I totally agree with it! 😅

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale[bot]]

Closing issue as stale.