mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-11-18 19:51:17 +00:00
bfb4a0ccc8
manual. * Removed some out-dated files from maintainers/docs. svn path=/nixpkgs/trunk/; revision=17419
175 lines
3.4 KiB
XML
175 lines
3.4 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
|
||
xmlns:xlink="http://www.w3.org/1999/xlink"
|
||
xml:id="chap-conventions">
|
||
|
||
<title>Coding conventions</title>
|
||
|
||
|
||
<section><title>Syntax</title>
|
||
|
||
<itemizedlist>
|
||
|
||
<listitem><para>Use 2 spaces of indentation per indentation level in
|
||
Nix expressions, 4 spaces in shell scripts.</para></listitem>
|
||
|
||
<listitem><para>Do not use tab characters, i.e. configure your
|
||
editor to use soft tabs. For instance, use <literal>(setq-default
|
||
indent-tabs-mode nil)</literal> in Emacs. Everybody has different
|
||
tab settings so it’s asking for trouble.</para></listitem>
|
||
|
||
<listitem><para>Use <literal>lowerCamelCase</literal> for variable
|
||
names, not <literal>UpperCamelCase</literal>. TODO: naming of
|
||
attributes in
|
||
<filename>all-packages.nix</filename>?</para></listitem>
|
||
|
||
<listitem><para>Function calls with attribute set arguments are
|
||
written as
|
||
|
||
<programlisting>
|
||
foo {
|
||
arg = ...;
|
||
}
|
||
</programlisting>
|
||
|
||
not
|
||
|
||
<programlisting>
|
||
foo
|
||
{
|
||
arg = ...;
|
||
}
|
||
</programlisting>
|
||
|
||
Also fine is
|
||
|
||
<programlisting>
|
||
foo { arg = ...; }
|
||
</programlisting>
|
||
|
||
if it's a short call.</para></listitem>
|
||
|
||
<listitem><para>In attribute sets or lists that span multiple lines,
|
||
the attribute names or list elements should be aligned:
|
||
|
||
<programlisting>
|
||
# A long list.
|
||
list =
|
||
[ elem1
|
||
elem2
|
||
elem3
|
||
];
|
||
|
||
# A long attribute set.
|
||
attrs =
|
||
{ attr1 = short_expr;
|
||
attr2 =
|
||
if true then big_expr else big_expr;
|
||
};
|
||
|
||
# Alternatively:
|
||
attrs = {
|
||
attr1 = short_expr;
|
||
attr2 =
|
||
if true then big_expr else big_expr;
|
||
};
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>Short lists or attribute sets can be written on one
|
||
line:
|
||
|
||
<programlisting>
|
||
# A short list.
|
||
list = [ elem1 elem2 elem3 ];
|
||
|
||
# A short set.
|
||
attrs = { x = 1280; y = 1024; };
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>Breaking in the middle of a function argument can
|
||
give hard-to-read code, like
|
||
|
||
<programlisting>
|
||
someFunction { x = 1280;
|
||
y = 1024; } otherArg
|
||
yetAnotherArg
|
||
</programlisting>
|
||
|
||
(especially if the argument is very large, spanning multiple
|
||
lines).</para>
|
||
|
||
<para>Better:
|
||
|
||
<programlisting>
|
||
someFunction
|
||
{ x = 1280; y = 1024; }
|
||
otherArg
|
||
yetAnotherArg
|
||
</programlisting>
|
||
|
||
or
|
||
|
||
<programlisting>
|
||
let res = { x = 1280; y = 1024; };
|
||
in someFunction res otherArg yetAnotherArg
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>The bodies of functions, asserts, and withs are not
|
||
indented to prevent a lot of superfluous indentation levels, i.e.
|
||
|
||
<programlisting>
|
||
{ arg1, arg2 }:
|
||
assert system == "i686-linux";
|
||
stdenv.mkDerivation { ...
|
||
</programlisting>
|
||
|
||
not
|
||
|
||
<programlisting>
|
||
{ arg1, arg2 }:
|
||
assert system == "i686-linux";
|
||
stdenv.mkDerivation { ...
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
<listitem><para>Function formal arguments are written as:
|
||
|
||
<programlisting>
|
||
{ arg1, arg2, arg3 }:
|
||
</programlisting>
|
||
|
||
but if they don't fit on one line they're written as:
|
||
|
||
<programlisting>
|
||
{ arg1, arg2, arg3
|
||
, arg4, ...
|
||
, # Some comment...
|
||
argN
|
||
}:
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
|
||
</itemizedlist>
|
||
|
||
</section>
|
||
|
||
|
||
<section><title>File naming and organisation</title>
|
||
|
||
<para>Names of files and directories should be in lowercase, with
|
||
dashes between words — not in camel case. For instance, it should be
|
||
<filename>all-packages.nix</filename>, not
|
||
<filename>allPackages.nix</filename> or
|
||
<filename>AllPackages.nix</filename>.</para>
|
||
|
||
</section>
|
||
|
||
|
||
</chapter> |