3 ms·

While it is right, that the red/blue distinction is annoying at times it is the consequence out of the event-loop based approach created in 1995. Any other solu

While it is right, that the red/blue distinction is annoying at times it is the consequence out of the event-loop based approach created in 1995. Any other solution would have broken that more. It is assumed that the code we have is single threaded. That not being the case anymore leads to tons of concurrency issues. Right now I know that all my code, till the next await, will run (mostly) uninterrupted by external influence. No locking needed, nothing will change behind my back etc. In a greenfield environment things certainly would look different, but unfortunately we are tied to past decisions till browser vendors decide to create an alternate universe (well, webassembly ...) and that has enough spread to rely on. But for that one would need agreement what that better future would be.

anonymoushn 5y ago
This isn't true. If you had stackful coroutines or something equivalent, you would be able to do all the things this thing does and you wouldn't have to pepper your callers and callers' callers with "await" whenever you add an operation that may take some time to a function for the first time. We had this in Python and still have it in Lua, C, Zig, and so on, but the world has mostly gone the other way.
- samatman 5y ago
  I happen to be working on an application which is largely written in Lua and uses the same event loop (libuv) as Node. I can confirm that with careful engineering, application code doesn't have to suffer from the color problem. Fundamentally the trick is to yield after creating a callback, and resume into that callback when the thread has more data to process. A `foo:bar():baz():bux()` chain can pause execution in any of those methods and the user doesn't have to know which (some knowledge of whether this will happen /at all/ is required, only because you need a coroutine since Lua can't yield the main thread). This isn't built-in, need to start with something like BEAM for that, but it's a nice sweet spot.
- poink 5y ago
  I think the issue they were getting at is code like this: function doSomething(doSomethingElse) { internalState.setUp(); doSomethingElse(); internalState.tearDown(); } Right now, you can safely assume this whole thing will execute to completion without anything else happening in the interim, so a lot of existing JS makes that assumption. If `doSomethingElse` can yield while other code executes the assumption becomes invalid.

anonymoushn 5y ago

This isn't true. If you had stackful coroutines or something equivalent, you would be able to do all the things this thing does and you wouldn't have to pepper your callers and callers' callers with "await" whenever you add an operation that may take some time to a function for the first time. We had this in Python and still have it in Lua, C, Zig, and so on, but the world has mostly gone the other way.

samatman 5y ago
I happen to be working on an application which is largely written in Lua and uses the same event loop (libuv) as Node. I can confirm that with careful engineering, application code doesn't have to suffer from the color problem. Fundamentally the trick is to yield after creating a callback, and resume into that callback when the thread has more data to process. A `foo:bar():baz():bux()` chain can pause execution in any of those methods and the user doesn't have to know which (some knowledge of whether this will happen /at all/ is required, only because you need a coroutine since Lua can't yield the main thread). This isn't built-in, need to start with something like BEAM for that, but it's a nice sweet spot.
poink 5y ago
I think the issue they were getting at is code like this: function doSomething(doSomethingElse) { internalState.setUp(); doSomethingElse(); internalState.tearDown(); } Right now, you can safely assume this whole thing will execute to completion without anything else happening in the interim, so a lot of existing JS makes that assumption. If `doSomethingElse` can yield while other code executes the assumption becomes invalid.