home-manager/modules/programs/man.nix
Damien Cassou 472ca211ca
man: support building manual page index cache
The apropos software is useful to get a list of manpages matching a
description or to get a list of all manpages. The latter feature is
used by Emacs to get manpage completion (`M-x man`).

To have apropos working, a database of all available manpages must be
built with mandb. This is what this commits does.

A similar change was done for NixOS:
edc6a76cc0
2020-09-13 20:52:08 +02:00

73 lines
2.3 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
{
options = {
programs.man = {
enable = mkOption {
type = types.bool;
default = true;
description = ''
Whether to enable manual pages and the <command>man</command>
command. This also includes "man" outputs of all
<literal>home.packages</literal>.
'';
};
generateCaches = mkOption {
type = types.bool;
default = false;
description = ''
Whether to generate the manual page index caches using
<citerefentry>
<refentrytitle>mandb</refentrytitle>
<manvolnum>8</manvolnum>
</citerefentry>. This allows searching for a page or
keyword using utilities like <citerefentry>
<refentrytitle>apropos</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>.
</para><para>
This feature is disabled by default because it slows down
building. If you don't mind waiting a few more seconds when
Home Manager builds a new generation, you may safely enable
this option.
'';
};
};
};
config = mkIf config.programs.man.enable {
home.packages = [ pkgs.man ];
home.extraOutputsToInstall = [ "man" ];
# This is mostly copy/pasted/adapted from NixOS' documentation.nix.
home.file = mkIf config.programs.man.generateCaches {
".manpath".text = let
# Generate a directory containing installed packages' manpages.
manualPages = pkgs.buildEnv {
name = "man-paths";
paths = config.home.packages;
pathsToLink = [ "/share/man" ];
extraOutputsToInstall = [ "man" ];
ignoreCollisions = true;
};
# Generate a database of all manpages in ${manualPages}.
manualCache = pkgs.runCommandLocal "man-cache" { } ''
# Generate a temporary man.conf so mandb knows where to
# write cache files.
echo "MANDB_MAP ${manualPages}/share/man $out" > man.conf
# Run mandb to generate cache files:
${pkgs.man-db}/bin/mandb -C man.conf --no-straycats --create \
${manualPages}/share/man
'';
in ''
MANDB_MAP ${config.home.profileDirectory}/share/man ${manualCache}
'';
};
};
}