Add support for Zsh as an alternative (or not) default (or not) interactive shell.

modules/module-list.nix

@@ -53,6 +53,7 @@
   ./programs/ssmtp.nix
   ./programs/venus.nix
   ./programs/wvdial.nix
+  ./programs/zsh/zsh.nix
   ./rename.nix
   ./security/apparmor.nix
   ./security/apparmor-suid.nix

modules/programs/zsh/zinputrc

@@ -0,0 +1,42 @@
+# Stolen from ArchWiki
+
+# create a zkbd compatible hash;
+# to add other keys to this hash, see: man 5 terminfo
+typeset -A key
+
+key[Home]=${terminfo[khome]}
+
+key[End]=${terminfo[kend]}
+key[Insert]=${terminfo[kich1]}
+key[Delete]=${terminfo[kdch1]}
+key[Up]=${terminfo[kcuu1]}
+key[Down]=${terminfo[kcud1]}
+key[Left]=${terminfo[kcub1]}
+key[Right]=${terminfo[kcuf1]}
+key[PageUp]=${terminfo[kpp]}
+key[PageDown]=${terminfo[knp]}
+
+# setup key accordingly
+[[ -n "${key[Home]}"     ]]  && bindkey  "${key[Home]}"     beginning-of-line
+[[ -n "${key[End]}"      ]]  && bindkey  "${key[End]}"      end-of-line
+[[ -n "${key[Insert]}"   ]]  && bindkey  "${key[Insert]}"   overwrite-mode
+[[ -n "${key[Delete]}"   ]]  && bindkey  "${key[Delete]}"   delete-char
+[[ -n "${key[Up]}"       ]]  && bindkey  "${key[Up]}"       up-line-or-history
+[[ -n "${key[Down]}"     ]]  && bindkey  "${key[Down]}"     down-line-or-history
+[[ -n "${key[Left]}"     ]]  && bindkey  "${key[Left]}"     backward-char
+[[ -n "${key[Right]}"    ]]  && bindkey  "${key[Right]}"    forward-char
+[[ -n "${key[PageUp]}"   ]]  && bindkey  "${key[PageUp]}"   beginning-of-buffer-or-history
+[[ -n "${key[PageDown]}" ]]  && bindkey  "${key[PageDown]}" end-of-buffer-or-history
+
+# Finally, make sure the terminal is in application mode, when zle is
+# active. Only then are the values from $terminfo valid.
+if (( ${+terminfo[smkx]} )) && (( ${+terminfo[rmkx]} )); then
+    function zle-line-init () {
+        printf '%s' "${terminfo[smkx]}"
+    }
+    function zle-line-finish () {
+        printf '%s' "${terminfo[rmkx]}"
+    }
+    zle -N zle-line-init
+    zle -N zle-line-finish
+fi

modules/programs/zsh/zsh.nix

@@ -0,0 +1,180 @@
+# This module defines global configuration for the zshell.
+
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  cfge = config.environment;
+
+  cfg = config.programs.zsh;
+
+  zshAliases = concatStringsSep "\n" (
+    mapAttrsFlatten (k: v: "alias ${k}='${v}'") cfg.shellAliases
+  );
+
+in
+
+{
+
+  options = {
+
+    programs.zsh = {
+
+      enable = mkOption {
+        default = false;
+        description = ''
+          Whenever to configure Zsh as an interactive shell.
+          Note that this tries to make Zsh the default
+          <option>users.defaultUserShell</option>,
+          which in turn means that you might need to explicitly
+          set this variable if you have another shell configured
+          with NixOS.
+        '';
+        type = types.bool;
+      };
+
+      shellAliases = mkOption {
+        default = config.environment.shellAliases;
+        description = ''
+          Set of aliases for zsh shell. See <option>environment.shellAliases</option>
+          for an option format description.
+        '';
+        type = types.attrs; # types.attrsOf types.stringOrPath;
+      };
+
+      shellInit = mkOption {
+        default = "";
+        description = ''
+          Shell script code called during zsh shell initialisation.
+        '';
+        type = types.lines;
+      };
+
+      loginShellInit = mkOption {
+        default = "";
+        description = ''
+          Shell script code called during zsh login shell initialisation.
+        '';
+        type = types.lines;
+      };
+
+      interactiveShellInit = mkOption {
+        default = "";
+        description = ''
+          Shell script code called during interactive zsh shell initialisation.
+        '';
+        type = types.lines;
+      };
+
+      promptInit = mkOption {
+        default = ''
+          autoload -U promptinit && promptinit && prompt walters
+        '';
+        description = ''
+          Shell script code used to initialise the zsh prompt.
+        '';
+        type = types.lines;
+      };
+
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    programs.zsh = {
+
+      shellInit = ''
+        . /etc/environment
+
+        ${cfge.shellInit}
+      '';
+
+      loginShellInit = cfge.loginShellInit;
+
+      interactiveShellInit = ''
+        ${cfge.interactiveShellInit}
+
+        ${cfg.promptInit}
+        ${zshAliases}
+
+        # Some sane history defaults
+        export SAVEHIST=2000
+        export HISTSIZE=2000
+        export HISTFILE=$HOME/.zsh_history
+
+        setopt HIST_IGNORE_DUPS SHARE_HISTORY
+      '';
+
+    };
+
+    environment.etc."zshenv".text =
+      ''
+        # /etc/zshenv: DO NOT EDIT -- this file has been generated automatically.
+        # This file is read for all shells.
+
+        # Only execute this file once per shell.
+        if [ -n "$__ETC_ZSHENV_SOURCED" ]; then return; fi
+        __ETC_ZSHENV_SOURCED=1
+
+        ${cfg.shellInit}
+
+        # Read system-wide modifications.
+        if test -f /etc/zshenv.local; then
+          . /etc/zshenv.local
+        fi
+      '';
+
+    environment.etc."zprofile".text =
+      ''
+        # /etc/zprofile: DO NOT EDIT -- this file has been generated automatically.
+        # This file is read for login shells.
+
+        # Only execute this file once per shell.
+        if [ -n "$__ETC_ZPROFILE_SOURCED" ]; then return; fi
+        __ETC_ZPROFILE_SOURCED=1
+
+        ${cfg.loginShellInit}
+
+        # Read system-wide modifications.
+        if test -f /etc/zprofile.local; then
+          . /etc/zprofile.local
+        fi
+      '';
+
+    environment.etc."zshrc".text =
+      ''
+        # /etc/zshrc: DO NOT EDIT -- this file has been generated automatically.
+        # This file is read for interactive shells.
+
+        # Only execute this file once per shell.
+        if [ -n "$__ETC_ZSHRC_SOURCED" -o -n "$NOSYSZSHRC" ]; then return; fi
+        __ETC_ZSHRC_SOURCED=1
+
+        . /etc/zinputrc
+
+        ${cfg.interactiveShellInit}
+
+        # Read system-wide modifications.
+        if test -f /etc/zshrc.local; then
+          . /etc/zshrc.local
+        fi
+      '';
+
+    environment.etc."zinputrc".source = ./zinputrc;
+
+    environment.systemPackages = [ pkgs.zsh ];
+
+    users.defaultUserShell = mkDefault "/run/current-system/sw/bin/zsh";
+
+    environment.shells =
+      [ "/run/current-system/sw/bin/zsh"
+        "/var/run/current-system/sw/bin/zsh"
+        "${pkgs.zsh}/bin/zsh"
+      ];
+
+  };
+
+}