elm

问题 As this answer shows it's possible in Elm 0.18 to run elm reactor with a custom HTML file if this snippet is included in the HTML file: <script src="/_compile/src/Main.elm"></script> <script> runElmProgram(); </script> In 0.19, however, it doesn't seem like the _compile directory exists or is served anymore. Is there another way to accomplish the same, preferably with elm reactor so as to be able to leverage existing IDE support etc., but I'm interested in any kind of "dev server" solution.

问题 I'm starting with Elm and when you want to set style you can simply embed it on your component: Html.Attribute.style List (String, String) But I can't find a way to get the style instead of set. What I need, actually, is the line-height (CSS attribute) of a specifc Html msg . I read a little about using a custom decoder (with Json.Decode.at ) but I still didn't get it. 回答1: Mateus, I'm just starting w/ elm so take this for what it's worth. When you receive an event you can interrogate the

问题 I'm wondering where I can find information about the " a " used in the Length example. It seems to be a type of some kind? 回答1: [1,2,3] is a List Int , functions that could only work with a Lists of Ints would have to have List Int in their type signature. ["a", "b"] is a List String , functions that could only work with a Lists of Strings would have to have List String in their type signature. A function that works with a list of any type (for example List.length ) can have a generic type

问题 I'm currently a student of FP. As I look around different syntax offer by different functional languages, I've come across a pattern in Elm sample code. I am curious about it. Here is the sample code myList = [{foo = "bar1"},{foo = "bar2"}] foos = myList |> List.map .foo In the last line here, List.map is being passed .foo . I believe this style is called point-free but what about the specific pattern of passing in an attribute to the List.map function? Is this a more common thing? Is it

问题 I'd like to separate the View and Update parts of a program into separate source files, but then, how do I share the Message and Subscriptions declarations ? 回答1: Think twice before splitting your modules, premature code splitting might be harmful to your project. Here is an example of the project structure I use in my Elm apps. Messages Html.App.map allows us to tag a message for child component, so we could pass it to Components.Counter.Update.update function, when keyboard subscription

问题 Is it possible to update a field in an Elm record via a function (or some other way) without explicitly specifying the precise field name? Example: > fields = { a = 1, b = 2, c = 3 } > updateField fields newVal fieldToUpdate = { fields | fieldToUpdate <- newVal } > updateField fields 5 .a -- does not work UPDATE: To add some context, I'm trying to DRY up the following code: UpdatePhraseInput contents -> let currentInputFields = model.inputFields in { model | inputFields <- {

问题 I am new to Elm and have been looking at the following example (note this is under the newer 0.17 architecture, where Action is now Command): http://elm-lang.org/examples/random There is a follow up challenge to add a second die to the example, so that a single click of the button rolls a new value for each die. My idea is to change the model to hold two separate values, one for each die, ala type alias Model = { dieFace1 : Int , dieFace2 : Int } This works fine until I get to the update

问题 I'm having trouble wrapping my head around decoding a bit complex JSON response in ELM. The JSON response structure(I have no control over it) doesn't match my application's data tree/model. What will the decoder code look like for this JSON ? I'm using NoRedInk's Json.Decode.Pipeline - http://package.elm-lang.org/packages/NoRedInk/elm-decode-pipeline/3.0.0/Json-Decode-Pipeline My project's Github repo - https://github.com/areai51/my-india-elm The JSON response - https://data.gov.in/node

问题 I am running an elm frontend via elm-reactor on localhost:8000 . It is supposed to load json files from a falcon backend running via gunicorn on localhost:8010 . This fails. The frontend is able to load static dummy files served by elm-reactor ( :8000 ) but when I try to replace the dummies by the actual backend ( :8010 ) it fails due to a missing header: Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:8010/api/sheets. (Reason:

问题 I am trying to parse a JSON file and show it to the user, here a simplified version { "posts": [{ // some properties comments: { // some more properties } } This is my code, I know it's a lot I'm not really sure what to remove to isolate the problem, every time I try I get a different error that seems to lead me nowhere. type Action = NoOp | GetPosts | ShowPosts (Maybe { posts : List Post.Model }) init = ( { posts = Nothing }, Effects.none ) update action model = case action of NoOp -> (