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5 <title>Haskell Mode for Emacs: Installation Guide</title>
9 <h1>Haskell Mode for Emacs: Installation Guide</h1>
11 <p>When Emacs is started up, it normally runs a file
12 called <code>~/.emacs</code> located in your home directory. This file
13 should contain all of your personal customisations written as a series of
14 Elisp commands. In order to install the Haskell mode, you have to tell
15 Emacs where to find it. This is done by adding some commands to the init
21 <li>If you are using XEmacs, the haskell-mode package should be
22 available for installation through the XEmacs package UI.
24 <li>If you are using Debian, you can install the package haskell-mode with
25 a command like "apt-get install haskell-mode".
31 <li>Download and unpack the basic mode and modules into a suitable
32 directory, e.g. <code>~/lib/emacs</code> where <code>~</code> stands for
35 <li><p>Assuming you have placed the basic
36 mode <code>haskell-mode.el</code> and the modules you want to use in
37 the directory <code>~/lib/emacs</code>, add the following command to
38 your init file (<code>~/.emacs</code>):</p>
40 <pre>(load "~/lib/emacs/haskell-site-file")</pre>
42 <p>adding the following lines according to which modules you want to
46 (add-hook 'haskell-mode-hook 'turn-on-haskell-doc-mode)
47 (add-hook 'haskell-mode-hook 'turn-on-haskell-indent)
48 (add-hook 'haskell-mode-hook 'turn-on-haskell-simple-indent)
51 <p>Note that the two indentation modules are mutually exclusive - add at
52 most one. <!-- You can download the above <a HREF=".emacs">code</a>. -->
53 Note that the line of code for simple indentation is commented out
54 (using a preceeding <code>;</code>) in preference for the more
55 advanced indentation module. Installation is now complete!</p>
57 <p>The other modules are automatically loaded when needed in the
60 <li>Font locking: just turn it on
61 via <code>global-font-lock-mode</code> or do
62 <pre>(add-hook 'haskell-mode-hook 'font-lock-mode)</pre>
63 <li>Declaration scanning: just use <code>M-x imenu</code> or
64 bind <code>imenu</code> to a key. E.g.
65 <pre>(global-set-key [(control meta down-mouse-3)] 'imenu)</pre>
66 or you can also add it to the menubar with
67 <pre>(add-hook 'haskell-mode-hook 'imenu-add-menubar-index)</pre>
68 <li>Interaction with inferior Haskell interpreter:
69 just hit <code>C-c C-z</code> or <code>C-c C-l</code>.
74 <p>For those interested, each command above shall now be explained.</p>
77 <li><p>We must ensure that the directory
78 containing <code>haskell-mode.el</code> is on
79 the <code>load-path</code> of Emacs. You can examine the value of
80 the <code>load-path</code> by typing <code>C-h v load-path</code> in
81 an Emacs session. Supposing that you've
82 placed <code>haskell-mode.el</code> in the
83 directory <code>~/lib/emacs</code>, if this directory is not on
84 the <code>load-path</code> we add it with:</p>
86 <pre>(setq load-path (cons "~/lib/emacs" load-path))</pre>
88 <p>The function <code>setq</code> sets the value of a variable, and the
89 function <code>cons</code> takes an element and a list and creates
90 a new list with the former as head and the latter as tail, as in
93 <li><p>It is possible (and desirable) for Emacs to enter a specific mode
94 according to the name of the file being edited/visited.
95 The variable <code>auto-mode-alist</code> tells Emacs what mode to run
96 according to which regular expression matches the filename. We wish
97 to run the Haskell mode on all files ending
98 in <code>.hs</code>, <code>.hi</code> (interface file)
99 and <code>.gs</code> (Gofer file), and to run the Haskell mode for
100 literate scripts on all files ending in <code>.lhs</code>
101 and <code>.lgs</code>. To do this, we need to add pairs of the
102 form <code>(<em>regexp</em> . <em>mode-function</em>)</code>. We use
103 the function <code>append</code> to append a list of three such pairs
104 to the end of the value of <code>auto-mode-alist</code>. A list in
105 Elisp is written within round parantheses with elements separated by
106 whitespace. A list is treated as a function application unless it is
107 quoted with <code>'</code>, which is what we do.</p>
109 <li><p>In order for Emacs to know where to find the definition of our mode
110 functions, <code>haskell-mode</code>
111 and <code>literate-haskell-mode</code>, we must use the
112 function <code>autoload</code>. Both mode functions can be found in
113 the file <code>haskell-mode.el</code> which was downloaded in the
114 first installation step (the <code>.el</code> extension is left off
115 and assumed by Emacs). As we have already ensured that this file is
116 on the <code>load-path</code> we need only give the filename and not
117 the directory. Its use is quite straightforward but for further
118 information, see its documentation by entering <code>C-h
119 f autoload</code> in an Emacs session.</p>
121 <li><p>Each function <code>turn-on-haskell-<em>module</em></code> turns on
122 the corresponding module. Adding such a function as a hook to the
123 Haskell mode will turn on that module when the mode is used.
124 Note that each of these modules may slow down Emacs, especially for
129 <h2>Customisation</h2>
131 <p>Most customisations are on the functionality of a particular module.
132 See the documentation of that module for information on its
137 <p>Any problems, do <a HREF="mailto:monnier@iro.umontreal.ca">mail</a> and we
138 will try our best to help you!</p>
140 <p><a HREF="./"><em>Haskell Mode Home Page</em></a>.</p>