Clojure Templates Are Easy With Leinigen

Using templates to create your Clojure projects can save you a lot of setup time and ensure your team is using the same base configuration and dependencies. There are templates on Clojars.org, however I’ll show you how easy it is to create your own with Leiningen.

I’ll create a simple template based on the leiningen default template, adding a section in the project.clj to give a custom propmt when run in the repl.

Templates used to be a Leinigen pluging called lein-newnew and its repo was the only doucmentation I found and was a little outdated. The plugin is now part of Leiningen and there are a few built in templates. There is also information via lein help new.

If you want to create a template in a more automatic way from a more complete project you created, take a look at the lein-create-template Leinignen plugin.

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Clean Git Commits With Emacs Magit

An effective way to have a clean and valuable commit history is to create the smallest valuable commit each time, with a descriptive commit message. This sounds obvious, but when you are in the midst of work things can get messy. Using Emacs Magit you can be highly selective as to what changes you include in each commit, down to individual characters.

This follows on from staging patches for cleaner commits with the command line, git add -p. Also see how to drive Git with Emacs and Magit for more background.

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Custom Powerline Theme for Emacs Modeline

Continuing my modeline customisation with powerline, I wanted to add colour to match the Cyberpunk theme of Emacs Live. To do this I copied the default them and custmised it, adding colours and chaning the style of seperatr. Here is how I customised the powerline code to make my own theme.

See how I previously tweaked Emacs modeline with powerline, as this article carries on from that. My modeline also includes an earlier tweak for the minor modes.

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Faster Clojure Repl Startup With Java 9 Snapshot

After upgrading to Java 8, Clojure development seemed faster due to quicker REPL startup times. So when I saw a snapshot of Java 9 had been released I was hopeful that startup performance would be even faster.

As Clojure runs on the Java Virtual machine (JVM), each time you start a REPL then you wait for a new JVM to start. Other than this REPL startup, Clojure feels faster than developing with Java directly.

Here is how I set up Java 9 Snapshot on my Linux laptop (Ubuntu 14.10), it should be the same for any decent operating system.

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Clojure With Light Table and Emacs Keybindings

When I teach people Clojure I use Light Table because it is really simple to use and its Instarepl gives instant feedback of the code as you type it. This feedback helps you understand Clojure quickly and gives you more confidence when coding.

As I do most of my Clojure development (and most everything else) in Emacs I really miss the excellent Emacs keybindings when I use Light Table. Luckily there is an Emacs plugin for Light Table, so here is a quick guide on how to install & use this Emacs plugin.

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Contributing to Open Source Projects

This holiday season give the gift of code… or anything else no matter how small to help out your favorite open source project. By joining the 24 pull reuests website with your Github account, you can challenge yourself to contribute to 24 projects through December.

Here are some reasons why you should contribute to open source projects.

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