I began to translate your tutorial in Russian language.
Which version It is better suited for translate en or en-v01?

"WRITE SOMETHING ABOUT THE UNIT TYPE OR LINK" appears at the bottom of section 2.2 http://www.elm-tutorial.org/signals/keeping_state.html#.

Now Elm doesn't have signals http://elm-lang.org/blog/farewell-to-frp Also this is migration guide https://github.com/elm-lang/elm-platform/blob/master/upgrade-docs/0.17.md

I find a handful of uses of the term action, sometime capitalized. It should be called msg instead.

The below line in View.elm causes compilation error (cycle dependency), so I think it should be removed 😃

File: elm-tutorial/jp/04-starting/07-multiple-modules.md

src / View.elm

import View exposing (view)

I don't agree that using a List over Maybe is a good idea. A better approach is to use Maybe.map, like:

Like so:

import Html exposing (..)

findItem id items =
    List.filter (\item -> item.id == id) items
        |> List.head

main =
  Maybe.map .id (findItem 2 [{id = 1}, {id = 2}])
    |> toString
    |> text

Please allow me to format all code examples with https://github.com/avh4/elm-format.
Consistent styling may help beginners to learn Elm coding style as they go through this wonderful tutorial. @sporto What do you think?

Feel free to close this issue if you think code styling is fine as it is.

Not sure if you want to explicitly tell people to put the RemoteData reference in, on book page Views under Fetching chapter, or whether by this point you want to start to expect people to work it out.

duplicate line in page Main in chapter Routing

import Models exposing (Model, initialModel)
import Models exposing (Model, initialModel)

Pull request #122 0.18 collapsed Html.App into Html so Html.App.map became Html.map.

This change is reflected in the code repo but not two places in the tutorial text for View.elm

page : Model -> Html Msg
page model =
    case model.route of
        PlayersRoute ->
            Html.App.map PlayersMsg (Players.List.view model.players)

        PlayerRoute id ->
            playerEditPage model id

        NotFoundRoute ->
            notFoundView

When I try and download the PDF or EPUB documents, I get the following error:

500
Server Error
Cannot find module 'html'
GitBook.com Status • Documentation • Contact Support

Hi! I'm currently going through this tutorial! Thanks it's amazing! :)
I would have a suggestion to update the players command section to use the Json.Decode.Pipeline library instead of Decode.map3. (http://package.elm-lang.org/packages/NoRedInk/elm-decode-pipeline/latest)

I also found the import Json.Decode as Decode a bit confusing in the type declarations afterwards e.g. Decode.Decoder (List Player)

I find it more straightfowared to do something like import Json.Decode exposing (Decoder) and then Decoder (List Player)

I could submit a PR for these changes if you agree!

Again thanks for the awesome tutorial!

First of all, I'd just like to say that elm-tutorial is an absolutely amazing resource for learning Elm. Haven't found any other tutorials that come close to it!

On section 3.8 Composing, I think a little more should be added about Signal.forwardTo (there's currently only one sentence). Seems there have been a few of people confused about forwardTo so I think it should be expanded on. Max Goldstein says "You're not alone. Signal.forwardTo is, in my opinion, the hardest function to understand in the entire standard library".

https://groups.google.com/d/msg/elm-discuss/qCs0_7ZsIsE/0h8gR8vKDAAJ

https://www.reddit.com/r/elm/comments/3ntbiq/how_does_signalforwardto_work/

on the page - Multiple modules

lines like
import Messages exposing (Msg)

need to be updated to
import Msgs exposing (Msg)

for those of cutting and pasting from the page to be able to build

http://www.elm-tutorial.org/020_signals/keeping_state.html

You're tutorial is awesome. Straight to the point, clear and accessible.

Thanks a lot for making it!

In the Type variables section of the Union Types page, you say:

In here we are saying the the a stand-in should be of type String.

shouldn't this be:

In here we are saying the a stand-in should be of type Int.

Or, change the signature of respond to:

respond: Answer String -> String

I was following along on the Mailbox example and understand much of what is explained, except when you describe the final code sample.

You did not get into much detail about the usage of mb. Specifically, I am confused on accessing mb.address and mb.signal. I am trying to break the mind frame of OOD, but this looks vaguely similar.

Could you elaborate on the main and view section? It combines many different concepts into one quiet quickly.

Thanks for the tutorial. Very helpful so far.

You may want to confirm this with another source (I'm new to typed languages), but I think e.g. Array in e.g. indexOf : String -> Array String -> Int is called a type constructor, might be worth adding to the book?

Ref: https://wiki.haskell.org/Constructor

Please review https://github.com/AwesomeFunGame/web-apps-with-elm/blob/AwesomeFunGame-Signals-Intro-patch-1/signals/introduction.md for proposed changes.

It would be great and handy for elm-tutorial to be able to clone elm-tutorial and run locally for offline reading. Is this possible?

Seciotn 11.5 - Can't compile when :
| DeletePlayer PlayerId
| DeletePlayerDone PlayerId (Result Http.Error ())
is not accounted for in the Players Update.

I just commented them out to get it to work, but maybe introduce them later when they are needed.

The tutorial is great and simple until it gets to Tasks and Effects, then it is way too complicated. I had to spend sometime in other resources to get more up to speed on it. But now I understand them enough to get through the tutorial.

I still don't have a handle on it without StartApp, loving those diagrams that show the flow though.
I'm going to go back and look at that scenario and see if I can figure it out.

If you could flesh out the beginner sections and maybe rearrange some of the explanations (since some of them happen after the first time we see it, by then I either got stuck or understood it already), it would be great!

Thanks for the tutorial!

Thanks for the amazing tutorial.

I've never used Yarn/WebPack before, hence I guess it's a Yarn issue. The generated package.json does not contain a scripts key-value, hence the sentence should say something like "replace or add to the top-level JSON Object".

I have notice that some code blocks doesn't have the syntax highlighting feature, is this intentional or do you think it should be resolve?

Example: 05-union-types.md

I can help you with that if you want me to.

Hello and thank you so much for the tutorial!

Can you update the code to use Hop version 4 (I see the current version is 4.0.3)?

I am trying to use it through the tutorial and since it requires to pass Config to navigateTo, I had moved the routerConfig into separate file along with type Route and PathMatchers declarations, so I would not have circular imports.

Thank you.

In the View section,

the function page causes a type mismatch

page : Model -> Html Msg
page model =
    case model.route of
        Models.PlayersRoute ->
            Players.List.view model.players

        Models.PlayerRoute id ->
            playerEditPage model id

        Models.NotFoundRoute ->
            notFoundView

where model.players is webData (List Player)

but Players.List.view expects List Player as its argument.

As the title says there's no explanation for what module Hello exposing (..) does in the hello world tutorial. That line is also missing from the hello world example page.

Two reader have reported that the fetching resources section doesn't work using 4.0.3. Investigate.

I'm not sure if I'm missing something obvious, but the section on Union types starts mentioning Yes and No, and keeps dragging it through all examples without ever explaining what this could be.

Having never written anything in Elm myself and this being my first time going though the tutorial, I cannot imagine what would type Yes and No be.

I understand the basic idea about union types, but the concrete example looks like it could use some improving.

It seems like it would be quicker to get the ancillary JSON API server up and running by just running json-server -w db.json -p 4000 as opposed to creating an api.js file to set it up.

Can you increase the font size in the .pdf version? Now it's too small, uncomfortable to read.

Would be nice if this book specified a license, for example, one of the Creative Commons licenses.

In https://www.elm-tutorial.org/en/08-edit/04-commands.html there is a typo.

"In src/Players/Commands.elm add:" should be "In src/Commands.elm add:"

Possibly rename 1.3 from "More on functions" to "Functions and Types", I feel it would be more descriptive of the actual contents it currently has.

The "Main view" navigation item is duplicated. I believe the first instance should be "Main update".

Hi folks, i don't know whether it's the right place, but i'll take the chance because you talk about the Elm Architecture.
So, it's all in the title. To illustrate my case, i'll use a case study.
Imagine you've got a child module whose UI is a text input, enriched with various things. As I enter text its model is updated. This child's model is held into the parent model.
you might tell me that from the parent's perspective, you just have to listen to the child's model and get anything you need out. Ok, but now, let's say you want a "enter" key stroke to notify that this word must be "sent" to its parent ... ok, you might suggest adding a bool knowing when i can use the proper input from the parent's perspective...
But now, the concept of Message (passing) is being replaced by data + bools ... not good at all.
So, here is the question : how to pass message from Child module to Parent module?
does the Elm architecture fit that way of building softwares ?

Thanks for your answer

Hi, thanks for the Tutorial, very useful.
For calibrating this "issue": I'm new to Elm with a strong Haskell background.

One thing I found disturbing is that Cmd felt magical. Elm seems very explicit about imports and Cmd is in scope without import. I suggest to add a short paragraph about what Cmd is and how it comes into scope in 02-elm-arch/02-structure.html -- right when Cmd is used. Presently, Cmd.none is given out w/o much explanation (or I missed a section). Maybe the application flow diagram could be usefully brought at this point. Another way to address this is to stress what consumes the Cmd when commenting the type of update : Msg -> Model -> ( Model, Cmd Msg ) .

I'm new to Elm, but I think that type variables are denoted by any lowercase identifier in the function signature. If this is the case, I think it should be mentioned in that section. If it's not true, then what is the syntax for specifying a type variable?

http://www.elm-tutorial.org/020_signals/keeping_state.html

With Elm 0.17.1 on Windows 10 using Brackets the hello world program in the tutorial compiles with the warning:

`missing type annotation
Top-level value 'main' does not have a type annotation.
I inferred the type annotation so you can copy it into your code:

main: Html.Html a

Successfully generated index.html`

It's just a warning though. The message "Hello" can be seen in the browser.

http://www.elm-tutorial.org/010_foundations/the_unit_type.html

Consider a type alias with a type variable

type alias is never explained.
Great tutorial thou :)

The rest of the chapter headings are clickable to jump straight to them. Additionally, "Improvements" does not have an arrow on the right side of the screen to jump to the next section. I suspect the "Tips and Tricks" needs an intro page of its own. I'll poke at this later if you'll accept a PR.

The Foundations: Functions section makes a lot of references to types and assumptions about the reader's knowledge of types. A short section before this point would be appropriate to introduce types and the types available within elm.

On the first step of the first page in which I'm supposed to type stuff in from,
https://www.elm-tutorial.org/en/01-foundations/01-hello.html
the first thing I type fails:

elm package install elm-lang/html

This gives me this error message:

Could not find command `package`. Maybe there is a typo?

Default commands include:

  make      Compile an Elm file or project into JS or HTML
  package   Manage packages from <http://package.elm-lang.org>
  reactor   Develop with compile-on-refresh and time-travel debugging
  repl      A REPL for running individual expressions

When you try to run the command `package` we actually search for an
  executable named elm-package. Are you able to run elm-package?
  Is it on your PATH?

There is no explanation for what to do when I get such an error. Should I continue learning?

in this topic I can't understand the following:

these functions:

updatePlayer : Player -> List Player -> List Player
updatePlayer updatedPlayer =
    let
        select existingPlayer =
            if existingPlayer.id == updatedPlayer.id then
                updatedPlayer
            else
                existingPlayer
    in
        List.map select

and

changeLevelCommands : PlayerId -> Int -> List Player -> List (Cmd Msg)
changeLevelCommands playerId howMuch =
    let
        cmdForPlayer existingPlayer =
            if existingPlayer.id == playerId then
                save { existingPlayer | level = existingPlayer.level + howMuch }
            else
                Cmd.none
    in
        List.map cmdForPlayer

we've got annotations for them

updatePlayer : Player -> List Player -> List Player
changeLevelCommands : PlayerId -> Int -> List Player -> List (Cmd Msg)

but they receives

updatePlayer updatedPlayer = ...
changeLevelCommands playerId howMuch = ...

Where List Player comes from?

The link on www.elm-tutorial.org "Read it online here" goes to the page you're on, not to a place with the tutorial contents.

In the "List over Maybe" section you make a good point about mapping being preferred to pattern matching, but, in addition to mapping over a list, you can map a maybe.

http://package.elm-lang.org/packages/elm-lang/core/4.0.1/Maybe#map

Hi,
Thanks for the great tutorial, can't find webpack.cofig file?

Thanks

After spending last night reading through the tutorial and playing with the online editor, I finally took the plunge and installed elm-platform and started playing around. I was pretty stumped when my Hello.elm crashed with a missing package error.

The Hello world example mentions the Html module being a part of core, which doesn't seem to be the case. Rather it is a separate package that needs to be installed using elm-package.

(The assets repo has an elm-package.json with a few deps listed, including elm-html.)

Did I make a mistake or is indeed the mishap in the tutorial? I'll be happy to send a patch to the Hello world -and other parts- as I garner valuable experience going through while actually doing the exercises, as long as it's not just another PEBKAC.

In the effects tutorial, You have forgotten to tell to install the effects package