title: Running cider-jack-in in emacs
body: <p>I would like to learn some Clojure, and I'm trying to run REPL from Emacs, but I cannot get it to work.</p>
  
  <p>I have created a basic project with <em>lein</em>. I open the generated file <em>core.clj</em> in Emacs, and when I try to run the REPL from it (by running the <em>cider-jack-in</em>), I just get the message:</p>
  
  <pre><code>Symbol's function definition is void: nil
  </code></pre>
  
  <p>I have toggled the debug-on-error, and the backtrace (several last lines) is:</p>
  
  <pre><code> Debugger entered--Lisp error: (void-function nil)
     nil(#&lt;buffer core.clj&gt;)
     #[257 "  !\203\207\300\207" [exclude predicate] 3 "\n\n(fn ELT)"](#&lt;buffer core.clj&gt;)
     seq-map(#[257 "  !\203\207\300\207" [exclude predicate] 3 "\n\n(fn ELT)"] (#&lt;buffer core.clj&gt; #&lt;buffer  *Minibuf-1*&gt; #&lt;buffer *Warnings*&gt; #&lt;buffer *GNU Emacs*&gt; #&lt;buffer *scratch*&gt; #&lt;buffer  *Minibuf-0*&gt; #&lt;buffer *Messages*&gt; #&lt;buffer  *code-conversion-work*&gt; #&lt;buffer  *Echo Area 0*&gt; #&lt;buffer  *Echo Area 1*&gt;))
     seq-filter(#[257 "r\211q\210\300\301!)\207" [derived-mode-p cider-repl-mode] 3 "\n\n(fn BUFFER)"] (#&lt;buffer core.clj&gt; #&lt;buffer  *Minibuf-1*&gt; #&lt;buffer *Warnings*&gt; #&lt;buffer *GNU Emacs*&gt; #&lt;buffer *scratch*&gt; #&lt;buffer  *Minibuf-0*&gt; #&lt;buffer *Messages*&gt; #&lt;buffer  *code-conversion-work*&gt; #&lt;buffer  *Echo Area 0*&gt; #&lt;buffer  *Echo Area 1*&gt;))
     cider-repl-buffers()
     cider-find-reusable-repl-buffer(nil "~/Development/languages/clojure/playground/test1/")
     cider-jack-in(nil)
  </code></pre>
  
  <p>When I run <strong>lein run</strong> in the terminal, the code runs properly.<br/>
  Also, when I run <strong>lein repl</strong> in the terminal, the REPL runs properly with the following info:</p>
  
  <pre><code>nREPL server started on port 62741 on host 127.0.0.1 - nrepl://127.0.0.1:62741
  REPL-y 0.3.7, nREPL 0.2.12
  Clojure 1.8.0
  Java HotSpot(TM) 64-Bit Server VM 1.8.0_45-b14
  </code></pre>
  
  <p>Lein has Cider version 0.14.0, while Emacs has downloaded version 0.15.0.</p>
  
  <p>Could anyone help me figure out which part of the setup I'm missing, or what I'm doing wrong?</p>
  
  <p>Thanks for the help!</p>
  
  <p>EDIT: Bellow is the contents of Emacs init file, with comments removed:</p>
  
  <pre><code>(require 'package)
  (add-to-list 'package-archives
             '("marmalade" . "http://marmalade-repo.org/packages/") t)
  (add-to-list 'package-archives
             '("tromey" . "http://tromey.com/elpa/") t)
  (add-to-list 'package-archives
             '("melpa" . "http://melpa.milkbox.net/packages/") t)
  
  (package-initialize)
  
  (when (not package-archive-contents)
    (package-refresh-contents))
  
  (defvar ido-cur-item nil)
  (defvar ido-default-item nil)
  (defvar ido-cur-list nil)
  (defvar predicate nil)
  (defvar inherit-input-method nil)
  
  (defvar my-packages
    '(paredit
      clojure-mode
      clojure-mode-extra-font-locking
      cider
      ido-ubiquitous
      smex
      projectile
      rainbow-delimiters
      tagedit
      magit))
  
  (if (eq system-type 'darwin)
      (add-to-list 'my-packages 'exec-path-from-shell))
  
  (dolist (p my-packages)
    (when (not (package-installed-p p))
      (package-install p)))
  
  (add-to-list 'load-path "~/.emacs.d/vendor")
  (add-to-list 'load-path "~/.emacs.d/customizations")
  
  (load "shell-integration.el")
  (load "navigation.el")
  (load "ui.el")
  (load "editing.el")
  (load "misc.el")
  (load "elisp-editing.el")
  (load "setup-clojure.el")
  (load "setup-js.el")
  </code></pre>