Christoph Frick - ofnir.net - Open Source Consultant, Software Developer and System Administrator (Posts about REPL)

WREPL now uses Clojure CLI

Christoph Frick - ofnir.net — Thu, 16 Jan 2025 23:00:00 GMT

WREPL no longer is a standalone program, but since version 0.2 now is integrated into the Clojure CLI. This makes it easier to use on a regular Clojurist machine. See the example-Folder on how to migrate.

Back when WREPL started there were no official way to quickly spin up a Clojure REPL any more. Spec was released, but was not part of the core. So before that you could just run a Clojure REPL with the JAR file in your ~/.m2/repository/org/clojure/ directory. But with the additional dependencies into the Spec libraries, this was no longer so easy.

So WREPL was again a single JAR to run your (standalone) REPL and also allowed configuration of all the "letters" of REPL and some additional stuff (e.g. loading dependencies, run some file on startup, ...). Nowadays, the Clojure CLI is installed on basically every Clojure developer machine and brings back the entry point to quickly spin up a REPL. It brings the facilities to run your own code and pull the dependencies for it.

Yet the part to configure a REPL to your liking is still a usable feature. Integrating "REPL-ish" tools with each other is not convenient. So WREPL remains useful still to e.g. use a different prompt to denote some other state than the current namespace or configure a pretty-printer to your liking in your rebel-readline REPL.

How to start a Clojure REPL since the Specs Alpha change

Christoph Frick - ofnir.net — Tue, 01 Aug 2017 22:00:00 GMT

With the recent change in Clojure to use dedicated artifacts for Spec in an alpha sub-namespace, it is no longer easy to start a simple REPL just with the regular jar (e.g. java -jar $CLOJURE_JAR clojure.main). So how to start it now?

As of before you are better off to do a lein new somewhere, change the org.clojure/clojure dependency to the version you like and do a lein deps :tree to fetch all that is needed and display what things org.clojure/core now depends on. E.g.

[org.clojure/clojure "1.9.0-alpha17"]
   [org.clojure/core.specs.alpha "0.1.10" :exclusions [[org.clojure/clojure] [org.clojure/spec.alpha]]]
   [org.clojure/spec.alpha "0.1.123" :exclusions [[org.clojure/clojure]]]

All your artifacts end up in ~/.m2/repository. So next you have to build up your classpath to call the REPL. You can either run a lein with-profile uberjar cp in that dummy project to get the class path Leiningen is using (which often can be quite long depending on all the plugins you run. Or you can guess the locations from the versions above to build up the params for -cp for yourself.

M2="$HOME/.m2/repository"
java -cp $M2/org/clojure/clojure/1.9.0-alpha17/clojure-1.9.0-alpha17.jar:$M2/org/clojure/spec.alpha/0.1.123/spec.alpha-0.1.123.jar:$M2/org/clojure/core.specs.alpha/0.1.10/core.specs.alpha-0.1.10.jar:. clojure.main

This is a very basic setup to get a basic REPL going, but paired with rlwrap this is a few times faster to fire up than a lein repl, which makes it perfect to quickly fool around with some ideas.

On the horizon to streamline this, there is https://github.com/clojure/tools.deps.alpha.

Clojure REST-REPL

Christoph Frick - ofnir.net — Fri, 22 Jan 2016 23:00:00 GMT

While tools like httpie give you a nice way to query web APIs, they only give you the means to query data easily and print the results nicely. Once you need to modify the results or need to drill down on them, you are on your own.

Therefor I wrote my own tool - REST REPL. It starts a Clojure REPL with some state handling (imagine cd from the shell), preloaded libraries, that make your live easier (clj-http, specter, clojure.data.xml, cheshire) and make it pretty print (with colors) the results using puget.

Since this is a (close to) regular Clojure REPL, you can handle the data as you are used too and you can place reoccurring code into functions.