2 Kindly

Kindly is a standard for requesting data visualizations in Clojure.

It specifies in what kinds of way Clojure forms and values should be displayed.

(ns kindly
  (:require [scicloj.kindly.v4.api :as kindly]
            [scicloj.kindly.v4.kind :as kind]
            [tablecloth.api :as tc]))

2.1 Why

Different tools have had different ways of writing notes. For example:

Anglican tutorials (source) - written in Gorilla REPL
thi-ng/geom viz examples (source) - written in Org-babel-clojure
Clojure2d docs (source1, source2) - written in Codox and Metadoc
Tablecloth API docs (source) - written in rmarkdown-clojure
R interop ClojisR examples (source) - written in Notespace v2
Bayesian optimization tutorial (source) - written in Nextjournal
scicloj.ml tutorials (source) - written in Notespace v3
Clojure2d color tutorial (source) - written in Clerk
Tablecloth documentation (source) - written in Kindly using Clay
…

2.2 Goal

Have a standard way to request data visualizations
for blog posts, books, slideshows, reports, dashboards, and interactive analyses,
that just will work across different tools,
without even mentioning those tools in the code.
We aim for copy/paste compatibility of visualisation code accross different tools:
- as it is a given for normal Clojure code producing textual output in a text oriented repl,
- visualisation code working in one tool should produce the same or very similar result in all compatible tools.

2.3 Status

supported by Clay
implemented a partially working adapter for Portal (kind-portal)
implemented a partially working adapter for Clerk (kind-clerk)
actively working to support other tools such as Cursive, Calva, and Clojupyter

2.4 Existing book/notebook projects using Kindly

Tablecloth documentation
Fastmath 3 documentation
ClojisR documentation
Wolframite documentation
Clay documentation
Kindly-noted - documenting the ecosystem around Kindly - WIP
Noj documentation - WIP
Clojure Tidy Tuesdays data-science explorations
Clojure Data Tutorials
Clojure Data Scrapbook
LLMs tutorial (in spanish) by Kyle Passarelli
Statistical Computing in Clojure: Functional Approaches to Unsupervised Learning by Jaryt Salvo

2.5 Example

Here is how one may request something of kind/md, which means Markdown:

(kind/md
 "hello *hello* **hello**")

hello hello hello

2.6 The set of kinds

(sort kindly/known-kinds)

(:kind/code
 :kind/cytoscape
 :kind/dataset
 :kind/echarts
 :kind/edn
 :kind/emmy-viewers
 :kind/fn
 :kind/fragment
 :kind/hiccup
 :kind/hidden
 :kind/highcharts
 :kind/html
 :kind/htmlwidgets-ggplotly
 :kind/htmlwidgets-plotly
 :kind/image
 :kind/map
 :kind/md
 :kind/mermaid
 :kind/observable
 :kind/plotly
 :kind/portal
 :kind/pprint
 :kind/println
 :kind/reagent
 :kind/scittle
 :kind/seq
 :kind/set
 :kind/smile-model
 :kind/table
 :kind/test
 :kind/test-last
 :kind/tex
 :kind/var
 :kind/vector
 :kind/vega
 :kind/vega-lite
 :kind/video)

You can find more (details and examples of using these kinds)[/kindly-noted/kinds.html] in the Kindly book.

2.7 How to use Kinds?

2.7.1 Attaching metadata to forms

^:kind/md
["hello *hello* **hello**"]

hello hello hello

^kind/md
["hello *hello* **hello**"]

hello hello hello

2.7.2 Attaching metadata to values

(-> ["hello *hello* **hello**"]
    kind/md)

hello hello hello

(-> ["hello *hello* **hello**"]
    kind/md
    meta
    :kindly/kind)

:kind/md

2.7.3 Attaching metadata to values - cont.

(-> "hello *hello* **hello**"
    kind/md
    meta
    :kindly/kind)

:kind/md

Values that cannot have metadata are wrapped in a vector before attaching metadata.

(-> "hello *hello* **hello**"
    kind/md
    kind/pprint)

["hello *hello* **hello**"]

(-> "hello *hello* **hello**"
    kind/md
    meta)

#:kindly{:kind :kind/md, :options {:wrapped-value true}}

2.7.4 Using values annotated by libraries

(defn my-library-function-for-big-big-text [text]
  (kind/hiccup
   [:big {:style {:background "#ccddcc"}}
    [:big text]]))

(-> "hello"
    my-library-function-for-big-big-text)

hello

(-> "hello"
    my-library-function-for-big-big-text
    (assoc-in [1 :style]
              {:background "#ddccdd"}))

hello

2.7.5 Automatically-inferred kinds

In certain situations, kinds are inferred without annotation. The kindly-advice library provides the default inference behaviour and an option to extend it.

For example, images:

(def clj-image
  (->  "https://upload.wikimedia.org/wikipedia/commons/e/eb/Ash_Tree_-_geograph.org.uk_-_590710.jpg"
       (java.net.URL.)
       (javax.imageio.ImageIO/read)))

Syntax error macroexpanding at (dev.clj:137:8).

Can’t get input stream from URL! Server returned HTTP response code: 403 for URL: https://upload.wikimedia.org/wikipedia/commons/e/eb/Ash_Tree_-geograph.org.uk-_590710.jpg

                                               clojure.core/eval                         core.clj: 3215
                                                             ...                                      
          jdk.internal.reflect.DirectMethodHandleAccessor.invoke  DirectMethodHandleAccessor.java:  103
                                      javax.imageio.ImageIO.read                     ImageIO.java: 1405
                                         java.net.URL.openStream                         URL.java: 1325
sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream      HttpsURLConnectionImpl.java:  223
      sun.net.www.protocol.http.HttpURLConnection.getInputStream           HttpURLConnection.java: 1615
     sun.net.www.protocol.http.HttpURLConnection.getInputStream0           HttpURLConnection.java: 2014
                    java.io.IOException: Server returned HTTP response code: 403 for URL: https://upload.wikimedia.org/wikipedia/commons/e/eb/Ash_Tree_-_geograph.org.uk_-_590710.jpg
             javax.imageio.IIOException: Can't get input stream from URL!
clojure.lang.Compiler$CompilerException: Syntax error macroexpanding at (dev.clj:137:8).
    data: #:clojure.error{:phase :execution,
                      :line 137,
                      :column 8,
                      :source "dev.clj"}

source: notebooks/kindly.clj