Ah, yes. Thank you!

Hi, is there any way to keep metadata after using clojure.walk/post-walk? I've tried the code below, but it returns nil

(meta (walk/postwalk
       (fn [v]
         (if (meta v)
           (with-meta v
             (meta v))
           v))
       (with-meta '(1 2 3)
         {:ar 2})))

I'm trying to build a native image to take a screenshot in clojure. The code is not that hard, but compiling to native images seems to fail. Or rather, I can build an image, but when running it, I get this exception:

Exception in thread "main" java.lang.IllegalArgumentException: AWT is currently not supported on Substrate VM
        at java.awt.Toolkit.getDefaultToolkit(Toolkit.java:37)
        at hosa$_main.invokeStatic(hosa.clj:14)
        at hosa$_main.doInvoke(hosa.clj:8)
        at clojure.lang.RestFn.invoke(RestFn.java:397)
        at clojure.lang.AFn.applyToHelper(AFn.java:152)
        at clojure.lang.RestFn.applyTo(RestFn.java:132)
        at hosa.main(Unknown Source)

This is my deps.edn:

{:paths ["src/main/clojure"]
 :aliases {:native-image
           {:main-opts ["-m clj.native-image hosa"
                        "--initialize-at-build-time"
                        "--initialize-at-run-time=java.awt.*"
                        ;; optional native image name override
                        "-H:Name=hosa"]
            :jvm-opts ["-Dclojure.compiler.direct-linking=true"]
            :extra-deps
            {clj.native-image
             {:git/url ""
              :sha "7708e7fd4572459c81f6a6b8e44c96f41cdd92d4"}}}}
 }

in my code, I added type hints (without them, I couldn't build the native image):

(ns hosa
  (:gen-class)
  (:import [java.awt GraphicsDevice GraphicsEnvironment Rectangle Robot Toolkit]
           .File
           java.awt.image.BufferedImage
           javax.imageio.ImageIO))

(defn -main [& _]
  (let [^Rectangle screen-rectangle (Rectangle. (.getScreenSize
                                                 ^Toolkit (Toolkit/getDefaultToolkit)))
        ^BufferedImage capture (.createScreenCapture ^Robot (Robot.) screen-rectangle)]
    (ImageIO/write ^BufferedImage capture "bmp" ^File (File. "printscreen.bmp"))
    ))

So, the question actually would be: how to add AWT to the substrate VM? (I get the same result with the --no-server option)

@kurt.sys the exception starts with AWT is currently not supported on Substrate VM so I would say you just can't

yeah... There's currently no workaround?

(I'm trying JavaFX, but that also doesn't seem to be supported - well, probably not a clj question anymore)

I have found this: https://github.com/gluonhq/substrate Seems to support JavaFX on Graal.

Hi How can I, with clojure.data.zip.xml/xml1-> navigate to text of first children inside tag? Imagine case where I have something like:

<names>
  <name>
    otwieracz
    <comment>
      ...
    </comment>
  </name>
  ...
</names>

I'd like to access otwieracz, so something more or less reassembling: (xml1-> xml :names :name first text)

but this does not work

can I create a multidimensional array of doubles with double-array? There's only the two following signatures:

[size-or-seq]
 [size init-val-or-seq]

Should next.jdbc be considered the successor to clojure.java.jdbc or will both be maintained indefinitely? Say if I were adding one of these to babashka, is next.jdbc preferred?

Yes

next.jdbc is the active code base

(read-string "#:db{:ident :class-desc/10-major-varies-by-season}") the above throws an error. Why is this valid :a/b-10 and this invalid :a/10-b?

It’s a long story, but the symbols can’t start with numbers

Keywords are “like symbols” in this respect

https://github.com/edn-format/edn#symbols

But there are some long standing now grandfathered in bugs that does allow it in keywords

But you’re seeing one of the cases where it will be marked invalid

its edn data that I am trying to read, its invalid for that too ?

Yes, code derived from there

hey, just discovered ^:const like

(def ^:const pi 3.14)

probably almost never

you should use it for true compile-time constants that should be compiled into code that uses it

this just came up on reddit - https://www.reddit.com/r/Clojure/comments/g48c53/why_is_there_no_constants_in_clojure_like_final/fnwfvh1/

Hello, getting the below error..

Applying task run to [-m tap-mssql.core --config /builds/config/config.json --discover]  Applying task javac to nil  Running javac with [@/tmp/.leiningen-cmdline13379584158302418975.tmp]  Applying task compile to nil  All namespaces already AOT compiled.

Any help would be highly appreciated

does clojure have a go-to markdown parsing library? I'm looking to parse markdown into hiccup if I can but HTML if not.

there's https://github.com/yogthos/markdown-clj . some rough edges like it parses a line at a time so the markdown must be a bit tidier than the spec allows

thanks, I'll check it out

I looked into this at length a while back. I would recommend https://github.com/atlassian/commonmark-java

are there some examples of using that from clojure?

(I've never really used the java interop that much before)

you can try convert markdown -> HTML -> hiccup

I saw some libraries to convert HTML into hiccup

And you can use hiccup for template rendering in clojure

thanks

@nihilazo Translating a bit of what is on their docs

Parser parser = Parser.builder().build();
HtmlRenderer renderer = HtmlRenderer.builder()
        .attributeProviderFactory(new AttributeProviderFactory() {
            public AttributeProvider create(AttributeProviderContext context) {
                return new ImageAttributeProvider();
            }
        })
        .build();

Node document = parser.parse("![text](/url.png)");
renderer.render(document);
// "<p><img src=\"/url.png\" alt=\"text\" class=\"border\" /></p>\n"

would be

(let [parser (-> (Parser/builder) (.build))
      renderer (-> (HtmlRenderer/builder)
                   (.attributeProviderFactory 
                     (reify AttributeProviderFactory
                         (create [this context]
                            (ImageAttributeProvider.))))
                   (.build))
      document (.parse parser "![text](/url.png)")]
  (.render renderer document))
    

thanks!

and since this is somewhat fun

class IndentedCodeBlockNodeRenderer implements NodeRenderer {

    private final HtmlWriter html;

    IndentedCodeBlockNodeRenderer(HtmlNodeRendererContext context) {
        this.html = context.getWriter();
    }

    @Override
    public Set<Class<? extends Node>> getNodeTypes() {
        // Return the node types we want to use this renderer for.
        return Collections.<Class<? extends Node>>singleton(IndentedCodeBlock.class);
    }

    @Override
    public void render(Node node) {
        // We only handle one type as per getNodeTypes, so we can just cast it here.
        IndentedCodeBlock codeBlock = (IndentedCodeBlock) node;
        html.line();
        html.tag("pre");
        html.text(codeBlock.getLiteral());
        html.tag("/pre");
        html.line();
    }
}

(defn indented-code-block-node-renderer [context]
  (let [html (.getWriter context)]
    (reify NodeRenderer
      (getNodeTypes [_]
        [IndentedCodeBlock])
      (render [_ node]
        (doto html
           (.line)
           (.tag "pre")
           (.text (.getLiteral node))
           (.tag "/pre")
           (.line))))))

thanks again

Isn't CommonMark PegDown based? It can get stuck on some edge cases. I researched about the same a few months back and found FlexMark-java better.

https://github.com/vsch/flexmark-java

I barely started to wrap flexmark: https://github.com/hindol/flexmark-clj Don't use this library, but maybe you can see how to do interop.

personal opinion don't ever look for clojure wrappers

look for good java libraries or native clojure things

and then evaluate if the clojure wrappings of those java things are worth it

if it just changes (.doThing (ThingDoer.) to (do-thing! (thing-doer))

you haven't gained much

but you have gained a vector for dependency rot

💯

learning the basic Java interop pays off dividends

just to reemphasize the point being made: there is a variety in Clojure libraries that wrap the underlying Java things. Some add a lot of leverage, some don't

Yeah, that's not a wrapper per se. I was trying to structurally parse a Markdown and the only library I found did Markdown -> HTML -> Hiccup. So, I wrote my own that will go from Markdown to Flexmark's tree of nodes to Clojure data structures.

I am confused by code in ring-codec at https://github.com/ring-clojure/ring-codec/blob/master/src/ring/util/codec.clj#L60

Why is url-encode doing all that by hand… but form-encode is using java’s URLEncoder

(form-encode* [unencoded encoding]
    (URLEncoder/encode unencoded encoding))

but URL encode is doing its own substitutions (which are using regexes and thus probably not very fast)

I had to look into something similar a couple of weeks ago - URLEncoder is not quite the same as URIEncode from Javascript, and not 100% the same as usual form/multipart encoding. I wouldn't worry about regex performance, usually that's not the bottleneck in request processing, especially if you're doing database calls etc

Is there a way to (set! *warn-on-reflection* true) for all namespaces in src and test directories? I use :global-vars {*warn-on-reflection* true} in defproject but that shows me warnings for deps also, e.g. a lot of CIDER warnings at startup.

Hi guys, I was compiling my project but got an error which I never have previously seen: Error building classpath. Could not transfer artifact com.taoensso:encore:jar:2.117.0 from/to clojars (): Range Not Satisfiable (416) Please help me resolve this if you have faced this before 🙏

Today in typos: If you call

(let [state (atom {})]
  (count @atom))

java.lang.ClassCastException: class clojure.core$atom cannot be cast to class java.util.concurrent.Future (clojure.core$atom is in unnamed module of loader 'app'; java.util.concurrent.Future is in module java.base of loader 'bootstrap')
 at clojure.core$deref_future.invokeStatic (core.clj:2298)
    clojure.core$deref.invokeStatic (core.clj:2320)
    clojure.core$deref.invoke (core.clj:2306)