elm practice

ELM Effect Manager Practice

Repository to help you understand the Effect Manager.

elm-reactor

# http://127.0.0.1:8000/src/CommandExample.elm
# http://127.0.0.1:8000/src/SubscriptionExample.elm

The explanation was detailed in the comments of the code below.

• Command Example: MyCounter.elm
• Subscription Example: MyKeyboard.elm (Completion)

What is an Effect Manager?

ELM, like Haskel, is a pure language. So if you want to create a library with side effects, it should not be a normal way. The module declaration should effect module be unusual in this way. This is called EFFECT Manager in the ELM community.

 effect module MyRandom where { command = MyCmd , subscription = MySub }
  exposing (
    ...

The problem is that how to make an Effect Manager is not explained anywhere. Even if you ask Elmlang Slack, most people know how to make an effect manager, and there are no good tutorials. In the official document, we can see and follow the Effect Managers in the libraries that are already made.

So I fixed Random.elm of the standard library and changed to a simple form that I could see and understand at a glance. Since I have been explained in detail as much as possible, I hope other developers can see and understand.

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