Add support for receive function

[wende]

How to process messages is still up to a debate:

Temporary solution:

Example:

case receive of
  Msg a -> 1

->

receive do
  {:msg, a} -> 1

But since it's impure, unidiomatic, and totally forbids a case of after block it should be discussed and redeveloped after

[OvermindDL1]

You could always support an after block by mandating it as part of the msg type like:

type Msg
  = Msg String
  | After Int
case receive of
  Msg a -> 1
  After 10 ->

Via the specially named message After or so?

And it is not technically impure, purity in Erlang is per process, and given the same inputs to the same process at the same time in its life cycle it will always generate the same work. ^.^

[wende]

Wow. This is a very smart and hacky idea. But I definitely like that!

[OvermindDL1]

Wow. This is a very smart and hacky idea. But I definitely like that!

The Elm syntax does not leave a lot of options open... ^.^;

[wende]

Because of the decisions on how to handle side effects and inherent impurity of receive construct, it won't ever be introduced to Elmchemy, and be possible to use only through special Elmchemy constructs for process message boxes

[OvermindDL1]

Maybe instead you could emulate it like a 'subscription', when a message is received that matches a pattern then send it on? Unsure of how to 'start' a receive though, hmm... Would be much easier if an Elm 'program' was exactly a GenServer on the Elixir side...

[wende]

After most of Elmchemy's features stabilize and prove themselves in a longer run I will start thinking about redoing Elm runtime in BEAM, so that there are effect modules, and generally pattern for generating side-effects. I just feel like receive is a very controversial feature to put into the project, and I believe it's sacrificing what's the best in Elm
I'm sure we'll find another way to achieve that