Aleš Najmann littleli

Introductory resources

High level overview https://yogthos.github.io/ClojureDistilled.html
Interactive exercises http://clojurescriptkoans.com/
More interactive exercises https://www.4clojure.com/
Community-powered Clojure courses https://clojurecademy.com/
Getting started guide https://grison.me/2020/04/04/starting-with-clojure/
Interactive book https://www.maria.cloud/
Interactive workbook http://viewer.gorilla-repl.org/view.html?source=github&user=lspector&repo=clojinc&path=worksheet.clj
Clojure by example https://github.com/inclojure-org/clojure-by-example

Spike

I looked into the state of GraalVM and Clojure and wrote some small work-related scripts.

GraalVM Build Tools

Downloaded GraalVM and set $GRAALVM_HOME
Found two main libraries for building GraalVM CLIs - https://github.com/luchiniatwork/cambada#packaging-as-a-native-image and https://github.com/taylorwood/clj.native-image (or https://github.com/taylorwood/lein-native-image for the lein equivalent). I chose clj.native-image as it seemed more focused on doing one thing well.
First tried its template example which was easy to follow.
Then added a graalvm build to one of our small cli tools
Found it to be pretty straightforward except for a stdout flushing issue that was trivial to fix

The Pledge

One thing that always made me a little sad about transducers was how map lost its ability to iterate multiple collections in parallel. This is actually my favorite feature of map. For example:

(map + (range 5) (range 5 10))
=> (5 7 9 11 13)

One somewhat practical use of this is if you want to compare two sequences, pairwise, using a comparator. Though I wish that every? took multiple collections, this is an adequate substitute:

	(ns fun.clojure.paillier
	(:import [java.math BigInteger]
	[java.security SecureRandom]
	[java.nio.charset StandardCharsets]))

	(defn- random-number! [end]
	(let [start (BigInteger/valueOf 2)
	interval (.subtract end start)
	i (BigInteger. (.bitCount interval) (SecureRandom.))]
	(.add start i)))

	package sandbox;

	import java.util.Arrays;
	import java.util.Random;

	public class SoABenchmark {

	public static Random rand = new Random(9001);
	public static int NUM_LABELS = 10;
	public static Struct[] aos;

	clj::littleli.clj-dremel=>
	; Syntax error compiling deftype* at (src/littleli/clj_dremel.clj:50:1).
	; Unable to resolve symbol: IDeref in this context
	[{:file "Compiler.java" :line 7115 :method "analyzeSeq" :flags [:tooling :java]}
	{:file "Compiler.java" :line 6789 :method "analyze" :flags [:tooling :java]}
	{:file "Compiler.java" :line 6745 :method "analyze" :flags [:dup :tooling :java]}
	{:file "Compiler.java" :line 6118 :method "parse" :flags [:tooling :java]}
	...]

	(ns strdist
	(:require [clojure.core.match :refer [match]]
	[clojure.string :as str]))

	(defn -distance
	[s1 s2]
	(match [s1 s2]
	[nil _] (.length s2)
	[_ nil] (.length s1)
	[([l & ls] :seq) ([r & rs] :seq)] (min (+ (if (= l r) 0 1) (-distance ls rs))

	class Clojure < Formula
	desc "The Clojure Programming Language"
	homepage "https://clojure.org"
	url "https://download.clojure.org/install/clojure-tools-1.10.1.510.tar.gz"
	sha256 "c6e003f612bdd7f9a9baa6d86deafb2d51b411310077c83c9ed13bc649c13b18"
	revision 1

	bottle :unneeded

	depends_on "rlwrap"

	# Check your changes compared to master with clj-kondo:
	git diff `git merge-base origin/master HEAD` --name-only \|grep -e '.clj$' \| (cd `git root`; xargs clj-kondo --lint)

	==== Testing JVM version
	==== Testing JVM version

	lein test clj-kondo.analysis-test

	lein test clj-kondo.compojure-test

	lein test clj-kondo.core-test

	lein test :only clj-kondo.core-test/run!-test