Docs about Elm Runtime

lydell · January 5, 2023, 11:09am

I find it very hard to follow many times

You’ll find the code in the various elm/* packages. For example:

elm/browser/blob/master/src/Elm/Kernel/Browser.js

/*

import Basics exposing (never)
import Browser exposing (Internal, External)
import Browser.Dom as Dom exposing (NotFound)
import Elm.Kernel.Debug exposing (crash)
import Elm.Kernel.Debugger exposing (element, document)
import Elm.Kernel.Json exposing (runHelp)
import Elm.Kernel.List exposing (Nil)
import Elm.Kernel.Platform exposing (initialize)
import Elm.Kernel.Scheduler exposing (binding, fail, rawSpawn, succeed, spawn)
import Elm.Kernel.Utils exposing (Tuple0, Tuple2)
import Elm.Kernel.VirtualDom exposing (appendChild, applyPatches, diff, doc, node, passiveSupported, render, divertHrefToApp)
import Json.Decode as Json exposing (map)
import Maybe exposing (Just, Nothing)
import Result exposing (isOk)
import Task exposing (perform)
import Url exposing (fromString)

*/

This file has been truncated. show original

github.com

elm/virtual-dom/blob/master/src/Elm/Kernel/VirtualDom.js

/*

import Basics exposing (identity)
import Elm.Kernel.Debug exposing (crash)
import Elm.Kernel.Json exposing (equality, runHelp, unwrap, wrap)
import Elm.Kernel.List exposing (Cons, Nil)
import Elm.Kernel.Utils exposing (Tuple2)
import Elm.Kernel.Platform exposing (export)
import Json.Decode as Json exposing (map, map2, succeed)
import Result exposing (isOk)
import VirtualDom exposing (toHandlerInt)

*/



// HELPERS


var _VirtualDom_divertHrefToApp;

This file has been truncated. show original

What I like to do, is opening some compiled Elm app JS in VSCode (or your editor/IDE of choice) and read through the code there. “Go to definition” and “parameter name inlay hints” help tremendously. At the same time, I keep the source code on GitHub open for cross reference, because sometimes things are called just a or b in the compiled code but maybe __callback in the source code.

You might also be interested in this repo:

It’s an attempt at documenting some things about the runtime and experimenting with a different implementation.

Topic		Replies	Views
How events works inside the virtual dom Learn	4	970	November 29, 2021
Use cases for effect manager Request Feedback	14	2333	March 15, 2020
Please help — how to start writing an Effect Manager module? Learn	2	1571	June 20, 2018
Are those downsides still valid today? Learn	12	2742	February 23, 2021
How do you handle runtime exceptions caused by extensions? Learn	20	2346	July 29, 2020

Docs about Elm Runtime

Related topics