Embed Directive in Clojure

Here’s the translation of the Go code to Clojure, formatted in Markdown suitable for Hugo:

Our first program will print the classic “hello world” message. Here’s the full source code.

(ns hello-world
  (:gen-class))

(defn -main [& args]
  (println "hello world"))

In Clojure, we define a namespace and a main function. The :gen-class directive is used to generate a Java class, which is necessary for creating an executable JAR file.

To run the program, save it in a file named hello_world.clj and use the Clojure command-line tool:

$ clj hello_world.clj
hello world

Sometimes we’ll want to build our programs into standalone JAR files. We can do this using the Clojure build tool, Leiningen.

First, create a project.clj file:

(defproject hello-world "0.1.0-SNAPSHOT"
  :description "Hello World example"
  :dependencies [[org.clojure/clojure "1.10.1"]]
  :main hello-world)

Then, use Leiningen to build the JAR:

$ lein uberjar
$ ls target
hello-world-0.1.0-SNAPSHOT-standalone.jar

We can then execute the built JAR file directly:

$ java -jar target/hello-world-0.1.0-SNAPSHOT-standalone.jar
hello world

Now that we can run and build basic Clojure programs, let’s learn more about the language.

Note: Clojure doesn’t have a direct equivalent to the embed directive used in the original example. Clojure typically handles resource embedding through the classpath and resource loading mechanisms. If you need to embed files in your Clojure application, you would typically include them in your project’s resources directory and access them at runtime using functions like clojure.java.io/resource.

For example, to read a file from the resources:

(ns hello-world
  (:require [clojure.java.io :as io]))

(defn read-resource [path]
  (slurp (io/resource path)))

(defn -main [& args]
  (println (read-resource "folder/single_file.txt")))

This approach allows you to include files in your JAR and access them at runtime, which is conceptually similar to the embed directive in the original example.