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nixpkgs/nixos/modules/programs/less.nix
Matt McHenry a2a0a58f7c
less: improve default settings (#139988)
* less: enable by default and set LESS=-R via lesskey

* since we set PAGER=less, programs.less.enable should default to
  true.

* some programs, notably git, set a custom LESS environment if none is
  present.  using the lesskey mechanism to set LESS=-R lets such
  programs continue to run less as they see fit.

This reverts commit 0e7b4e60a8.

* less: remove use of deprecated lesskey binary format

* less: enable in environment.nix rather than less.nix

per discussion in #139988
2021-10-05 11:13:48 +02:00

135 lines
3.7 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.programs.less;
configText = if (cfg.configFile != null) then (builtins.readFile cfg.configFile) else ''
#command
${concatStringsSep "\n"
(mapAttrsToList (command: action: "${command} ${action}") cfg.commands)
}
${if cfg.clearDefaultCommands then "#stop" else ""}
#line-edit
${concatStringsSep "\n"
(mapAttrsToList (command: action: "${command} ${action}") cfg.lineEditingKeys)
}
#env
${concatStringsSep "\n"
(mapAttrsToList (variable: values: "${variable}=${values}") cfg.envVariables)
}
'';
lessKey = pkgs.writeText "lessconfig" configText;
in
{
options = {
programs.less = {
# note that environment.nix sets PAGER=less, and
# therefore also enables this module
enable = mkEnableOption "less";
configFile = mkOption {
type = types.nullOr types.path;
default = null;
example = literalExpression ''"''${pkgs.my-configs}/lesskey"'';
description = ''
Path to lesskey configuration file.
<option>configFile</option> takes precedence over <option>commands</option>,
<option>clearDefaultCommands</option>, <option>lineEditingKeys</option>, and
<option>envVariables</option>.
'';
};
commands = mkOption {
type = types.attrsOf types.str;
default = {};
example = {
h = "noaction 5\\e(";
l = "noaction 5\\e)";
};
description = "Defines new command keys.";
};
clearDefaultCommands = mkOption {
type = types.bool;
default = false;
description = ''
Clear all default commands.
You should remember to set the quit key.
Otherwise you will not be able to leave less without killing it.
'';
};
lineEditingKeys = mkOption {
type = types.attrsOf types.str;
default = {};
example = {
e = "abort";
};
description = "Defines new line-editing keys.";
};
envVariables = mkOption {
type = types.attrsOf types.str;
default = {
LESS = "-R";
};
example = {
LESS = "--quit-if-one-screen";
};
description = "Defines environment variables.";
};
lessopen = mkOption {
type = types.nullOr types.str;
default = "|${pkgs.lesspipe}/bin/lesspipe.sh %s";
defaultText = literalExpression ''"|''${pkgs.lesspipe}/bin/lesspipe.sh %s"'';
description = ''
Before less opens a file, it first gives your input preprocessor a chance to modify the way the contents of the file are displayed.
'';
};
lessclose = mkOption {
type = types.nullOr types.str;
default = null;
description = ''
When less closes a file opened in such a way, it will call another program, called the input postprocessor, which may perform any desired clean-up action (such as deleting the replacement file created by LESSOPEN).
'';
};
};
};
config = mkIf cfg.enable {
environment.systemPackages = [ pkgs.less ];
environment.variables = {
LESSKEYIN_SYSTEM = toString lessKey;
} // optionalAttrs (cfg.lessopen != null) {
LESSOPEN = cfg.lessopen;
} // optionalAttrs (cfg.lessclose != null) {
LESSCLOSE = cfg.lessclose;
};
warnings = optional (
cfg.clearDefaultCommands && (all (x: x != "quit") (attrValues cfg.commands))
) ''
config.programs.less.clearDefaultCommands clears all default commands of less but there is no alternative binding for exiting.
Consider adding a binding for 'quit'.
'';
};
meta.maintainers = with maintainers; [ johnazoidberg ];
}