Learning clojure with emacs

This is my workflow for learning both emacs and clojure

• All editing, git and repl work done in emacs
• Learn snippets and execute them in repl, then writing a test to describe what it does
• Any wordy notes about clojure in here
• A little every day is better than a lot every 2 weeks

Why Clojure?

• Uniform syntax.
• Code is data
• Immutablility encouraged
• http://learnxinyminutes.com/docs/clojure/
• http://www.4clojure.com/problem/8#prob-title
• http://www.braveclojure.com/
• Revenge of the nerds http://www.paulgraham.com/icad.html

Why lisp? (all from the book)

• Enables meta programming (macros). Reprogram the language. You freaks.
• "Sometimes you want to change what words mean"
• "Redefine private to mean private for production but public for dev" (eugh, really?)
• "Redefine class to provide callback hooks for life-cycle events, for eg an event on creation"
• "Millions of lines of code written around missing language features"

EMBRACE THE REPLZ.

(find-doc "xor") ftw

Writing clojure in emacs

https://github.com/clojure-emacs/cider is the emacs package for enabling this.

Running the repl

M-x cider-jack-in

At the end of a line do c-x c-e to evaluate it in the repl

C-c M-n sets the repl's namespace to whatever is defined in the open file

C-c C-k compiles the clojure file in the repl

C-c M-i inspects an expression, so you can see what sub forms do

Interesting one in terms of "purity" is C-c C-w which evaluates the preceeding form and replaces it with it's result

When you get some kind of stacktrace window you can get rid of it with q. If you want it back it will be in a buffer called cider-error

C-M-\ reformats selected region (C-SPACE to mark regions)

Paredit

A minor mode which closes the lisp parenthesis. There are key bindings to navigate through them

Given (+ 1 2 3 4) you can put the point (cursor) before 2 for example and typem-( which will put paranthesis around 2

You can then "slup" an argument into the current paranthesis with c-right arrow. Doing left arrow will do the opposite

Moving between beginning and end of forms is with C-M-f (forward) and C-M-b (backward)

https://github.com/georgek/paredit-cheatsheet/blob/master/paredit-cheatsheet.pdf?raw=true

Auto complete

(global-company-mode)

Tests

m-x cider-run-tests or c-c , runs all tests for the current namespace

It seems you have to run c-c c-k to compile the code first though. Surely that can be fixed

Other commands

m-. will jump to symbol