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Init a task in a module + avoid circular import?

via Elm - Latest posts by @pdamoc Peter Damoc on Fri, 18 Sep 2020 03:30:39 GMT

You can pass arguments (like the current time if you got it as a flag) to the init from another module.

Can you provide more information about this? init is just a regular function, it is not obvious why it would need a view. In any case, an empty view is usually text "".

Init a task in a module + avoid circular import?

via Elm - Latest posts by @Yannick971 Yannick on Fri, 18 Sep 2020 00:02:39 GMT

Newbie question… There is a value from the model of Main.elm that I would need to access in a module, the module being itself imported in Main…hence the circular import…
is there a way around this, or I just have to rethink my design?
I believe it’s the latter…

At first, I wanted to have this value computed in the module, not in Main, but I needed it to be initialized on the app startup. (This value is computed from the current time, to give you context).
Is there a way to initialize this task in a module, on app startup? I guess so but I couldnt figure it out. Can I just use init without view? Is there something like view.None to tell Elm there is no view here ?

So I ended up doing this in the Main init and it created this circular import bug because I was importing the value from Main into the module…

JSON decode unknown number of fields

via Elm - Latest posts by @iwtilma on Thu, 17 Sep 2020 21:04:39 GMT

Thanks for this solution too. For now I don’t need the order, but I will keep this in mind for future development.

Alexander Artemenko: cl-emb

via Planet Lisp by on Thu, 17 Sep 2020 19:47:58 GMT

This is an interesting templating library. The most interesting features are:

• named template pieces can call each other;
• debug mode allows to inspect generated code;
• different escape methods.

Here is how template functions can be reused:

POFTHEDAY> (cl-emb:register-emb "user-list"
            "
<ul>
  <% @loop users %>
    <li><% @call user %></li>
  <% @endloop %>
</ul>
")

POFTHEDAY> (cl-emb:register-emb "user"
            "<a href=\"/users/<% @var nickname %>\"><% @var name %></a>")

POFTHEDAY> (cl-emb:execute-emb "user-list"
             :env '(:users
                    ((:nickname "bob"
                      :name "Bob Hopkins")
                     (:nickname "alice"
                      :name "Alice Cooker"))))
"
<ul>
  
    <li><a href=\"/users/bob\">Bob Hopkins</a></li>
  
    <li><a href=\"/users/alice\">Alice Cooker</a></li>
  
</ul>
"

Let's see which code was generated for "user-list". To make this work, we'll need to set *debug* variable and recompile the template:

POFTHEDAY> (cl-emb:pprint-emb-function "user-list")

(LAMBDA
    (
     &KEY CL-EMB-INTERN::ENV CL-EMB-INTERN::GENERATOR-MAKER
     CL-EMB-INTERN::NAME)
  (DECLARE (IGNORABLE CL-EMB-INTERN::ENV CL-EMB-INTERN::GENERATOR-MAKER))
  (LET ((CL-EMB-INTERN::TOPENV CL-EMB-INTERN::ENV)
        (CL-EMB-INTERN::TEMPLATE-PATH-DEFAULT
         (IF (TYPEP CL-EMB-INTERN::NAME 'PATHNAME)
             CL-EMB-INTERN::NAME
             *DEFAULT-PATHNAME-DEFAULTS*)))
    (DECLARE
     (IGNORABLE CL-EMB-INTERN::TOPENV CL-EMB-INTERN::TEMPLATE-PATH-DEFAULT))
    (WITH-OUTPUT-TO-STRING (*STANDARD-OUTPUT*)
      (PROGN
       (WRITE-STRING "
<ul>
  ")
       (DOLIST
           (CL-EMB-INTERN::ENV
            (CL-EMB::AUTOFUNCALL (CL-EMB::GETF-EMB "users")))
         (WRITE-STRING "
    <li>")
         (FORMAT T "~A"
                 (LET ((CL-EMB:*ESCAPE-TYPE* CL-EMB:*ESCAPE-TYPE*))
                   (CL-EMB:EXECUTE-EMB "user" :ENV CL-EMB-INTERN::ENV
                                       :GENERATOR-MAKER
                                       CL-EMB-INTERN::GENERATOR-MAKER)))
         (WRITE-STRING "</li>
  "))
       (WRITE-STRING "
</ul>
")))))

As you can see, cl-emb generates a straight forward Lisp code.

Now let's check how fast cl-emb is and compare it to HTML template engines reviewed in previous days:

POFTHEDAY> (cl-emb:register-emb "render"
             "
<title><% @var title %></title>
<ul>
<% @loop items %><li><% @var value %></li><% @endloop %>
</ul>
")

POFTHEDAY> (time
            (loop repeat 1000000
                  do (cl-emb:execute-emb "render"
                       :env '(:title "Foo Bar"
                              :items ((:value "One")
                                      (:value "Two")
                                      (:value "Three"))))))
Evaluation took:
  1.436 seconds of real time
  1.441475 seconds of total run time (1.421158 user, 0.020317 system)
  [ Run times consist of 0.104 seconds GC time, and 1.338 seconds non-GC time. ]
  100.35% CPU
  3,172,183,256 processor cycles
  767,974,304 bytes consed

That is pretty fast. Slightly slower than Spinneret but faster than Zenekindarl.

To learn more about cl-emb's features, read it's docs!

Skinney/murmur3 not downloading

via Elm - Latest posts by @evancz Evan on Thu, 17 Sep 2020 19:00:13 GMT

I believe the root issue is a user name change on GitHub, from Skinney to robinheghan, which ends up changing the hashes for releases.

I sent some chats to @robin.heggelund of possible paths and how I can help if needed, but in the meantime, you can get your CI unstuck by placing the following directory on it:

~/.elm/0.19.1/packages/Skinney/murmur3/2.0.8

You should have this on your local development system.

Zip it up, and add a temporary line before you run any Elm stuff to place this directory on the CI machine.

CI Note: I very highly highly highly encourage people with CI to cache your ~/.elm directory from build to build. This will make you immune to DNS issues, GitHub downtime, or things like this scenario! That directory just contains (1) static files that have been downloaded and (2) the build artifacts they produce deterministically. The one thing that can go wrong is acquiring the files over HTTP!

Hashing Note: The current design for hashing was chosen under the assumption that hashes of GitHub zip files would be based strictly on the content of the files, but it appears that incidental information about how GitHub hosts things also makes its way into these hashes. It is stable in general, but certain things can knock it out of whack. So I’d like to switch how hashes are generated to an approach that takes longer, but cannot be tripped up by these details. This is an infrastructure that’s much larger than it sounds, but it is highest priority for any package work.

Skinney/murmur3 not downloading

via Elm - Latest posts by @hexedhash Giorgio on Thu, 17 Sep 2020 18:16:26 GMT

I am seeing the following stack trace in my ci/cd pipeline when installing elm packages.

2:08:33 PM: Starting downloads...
2:08:33 PM:   ✗ Skinney/murmur3 2.0.8
2:08:33 PM:   ● elm/random 1.0.0
2:08:33 PM:   ● elm/regex 1.0.0
2:08:33 PM:   ● elm/time 1.0.0
2:08:33 PM:   ● elm/html 1.0.0
2:08:33 PM:   ● elm/parser 1.1.0
2:08:33 PM:   ● truqu/elm-base64 2.0.4
2:08:33 PM:   ● elm/browser 1.0.2
2:08:33 PM:   ● elm/virtual-dom 1.0.2
2:08:33 PM:   ● elm/bytes 1.0.8
2:08:33 PM:   ● elm/url 1.0.0
2:08:33 PM:   ● rtfeldman/elm-hex 1.0.0
2:08:33 PM:   ● elm/svg 1.0.1
2:08:33 PM:   ● elm/http 2.0.0
2:08:33 PM:   ● elm/json 1.1.3
2:08:33 PM:   ● elm/core 1.0.5
2:08:33 PM:   ● elm/file 1.0.5
2:08:33 PM:   ● elm-explorations/test 1.2.2
2:08:33 PM:   ● pablohirafuji/elm-syntax-highlight 3.3.0
2:08:33 PM:   ● rtfeldman/elm-css 16.0.1
2:08:33 PM: Verifying dependencies (19/20)
2:08:33 PM: Verifying dependencies (20/20)-- CORRUPT PACKAGE DATA --------------------------------------------------------
2:08:33 PM: I downloaded the source code for Skinney/murmur3 2.0.8 from:
2:08:34 PM: Failed during stage 'building site': Build script returned non-zero exit code: 1
2:08:33 PM:     https://github.com/Skinney/murmur3/zipball/2.0.8/
2:08:33 PM: But it looks like the hash of the archive has changed since publication:
2:08:33 PM:   Expected: 81a0bada79740ae806df04b1bb14a7d64f763ac5
2:08:33 PM:     Actual: 931398ec656078e26b2e29520cd283ffe6e8e441
2:08:33 PM: This usually means that the package author moved the version tag, so report it
2:08:33 PM: to them and see if that is the issue. Folks on Elm slack can probably help as
2:08:33 PM: well.

Is anyone else running into this?

cc @robin.heggelund

JSON decode unknown number of fields

via Elm - Latest posts by @iwtilma on Thu, 17 Sep 2020 17:21:06 GMT

Thank you, stephenreddek, for your clear answer. I try to make it work using Json.Decode.keyValuePairs, but that raises a question: are you sure about the pipeline with Json.Decode.map ((key, value) -> value)? Elm doesn’t accept it:

The argument is:

    Decoder (List ( String, String ))

But (|>) is piping it to a function that expects:

    Decoder ( a, value )

I could keep the list of key-value pairs and map them into values only later using List.map. What do you suggest?

"fold" animation in elm-css

via Elm - Latest posts by @eimfach Robin G. on Thu, 17 Sep 2020 16:54:00 GMT

Why does that seem hacky to you? The dynamic height needs a dynamic solution … If the css transition does require a fixed height, this seems straightforward…

"fold" animation in elm-css

via Elm - Latest posts by @hexedhash Giorgio on Thu, 17 Sep 2020 16:36:45 GMT

cc @Lucas_Payr

… (had to add extra chars to post the comment haha)

JSON decode unknown number of fields

via Elm - Latest posts by @iwtilma on Thu, 17 Sep 2020 16:18:33 GMT

I want to decode a JSON object that looks like this:

{ 
  "boxes" : {
    "1" : { 
      "items" : {
        "1" : "pencil",
        "2" : "ball"
      },
    },
    "2" : { 
      "items" : {
        "1" : "teapot",
        "2" : "spoon",
        "3" : "towel"
      }
    }
  }
}

I have no control over the JSON format. I get it from an external server.
My problem while decoding is that I don’t know how many boxes the JSON contains nor how many items each box contains.
I would like to decode it into a List of boxes that contains a List of items. How should I approach this?

Thanks in advance!

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