emacs: Add popup interface for guix commands.

* emacs/guix-command.el: New file.
* emacs.am (ELFILES): Add it.
* doc/emacs.texi (Emacs Initial Setup): Mention 'magit-popup' library.
  (Emacs Popup Interface): New node.
  (Emacs Interface): Add it.
* doc/guix.texi (Top): Likewise.

4 files changed, 695 insertions, 0 deletions

diff --git a/doc/emacs.texi b/doc/emacs.texi
index 5fa15d7783..db2e657d27 100644
--- a/doc/emacs.texi
+++ b/doc/emacs.texi
@@ -9,6 +9,7 @@ Guix convenient and fun.
 @menu
 * Initial Setup: Emacs Initial Setup.	Preparing @file{~/.emacs}.
 * Package Management: Emacs Package Management.	Managing packages and generations.
+* Popup Interface: Emacs Popup Interface.	Magit-like interface for guix commands.
 * Prettify Mode: Emacs Prettify.	Abbreviating @file{/gnu/store/@dots{}} file names.
 * Completions: Emacs Completions.       Completing @command{guix} shell command.
 @end menu
@@ -35,6 +36,12 @@ later;
 @uref{http://nongnu.org/geiser/, Geiser}, version 0.3 or later: it is
 used for interacting with the Guile process.
 
+@item
+@uref{https://github.com/magit/magit/, magit-popup library}.  You
+already have this library if you use Magit 2.1.0 or later.  This library
+is an optional dependency---it is required only for @kbd{M-x@tie{}guix}
+command (@pxref{Emacs Popup Interface}).
+
 @end itemize
 
 When it is done ``guix.el'' may be configured by requiring a special
@@ -486,6 +493,43 @@ Various settings for ``info'' buffers.
 @end table
 
 
+@node Emacs Popup Interface
+@section Popup Interface
+
+If you ever used Magit, you know what ``popup interface'' is
+(@pxref{Top,,, magit-popup, Magit-Popup User Manual}).  Even if you are
+not acquainted with Magit, there should be no worries as it is very
+intuitive.
+
+So @kbd{M-x@tie{}guix} command provides a top-level popup interface for
+all available guix commands.  When you select an option, you'll be
+prompted for a value in the minibuffer.  Many values have completions,
+so don't hesitate to press @key{TAB} key.  Multiple values (for example,
+packages or lint checkers) should be separated by commas.
+
+After specifying all options and switches for a command, you may choose
+one of the available actions.  The following default actions are
+available for all commands:
+
+@itemize
+
+@item
+Run the command in the Guix REPL.  It is faster than running
+@code{guix@tie{}@dots{}} command directly in shell, as there is no
+need to run another guile process and to load required modules there.
+
+@item
+Run the command in a shell buffer.  You can set
+@code{guix-run-in-shell-function} variable to fine tune the shell buffer
+you want to use.
+
+@item
+Add the command line to the kill ring (@pxref{Kill Ring,,, emacs, The
+GNU Emacs Manual}).
+
+@end itemize
+
+
 @node Emacs Prettify
 @section Guix Prettify Mode
 
diff --git a/doc/guix.texi b/doc/guix.texi
index cb5bbab2a0..89291273c4 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -112,6 +112,7 @@ Emacs Interface
 
 * Initial Setup: Emacs Initial Setup.	Preparing @file{~/.emacs}.
 * Package Management: Emacs Package Management.	Managing packages and generations.
+* Popup Interface: Emacs Popup Interface.	Magit-like interface for guix commands.
 * Prettify Mode: Emacs Prettify.	Abbreviating @file{/gnu/store/@dots{}} file names.
 * Completions: Emacs Completions.       Completing @command{guix} shell command.
 
diff --git a/emacs.am b/emacs.am
index e3f2001e8f..bf91cca0bb 100644
--- a/emacs.am
+++ b/emacs.am
@@ -21,6 +21,7 @@ AUTOLOADS = emacs/guix-autoloads.el
 ELFILES =					\
   emacs/guix-backend.el				\
   emacs/guix-base.el				\
+  emacs/guix-command.el				\
   emacs/guix-emacs.el				\
   emacs/guix-help-vars.el			\
   emacs/guix-history.el				\
diff --git a/emacs/guix-command.el b/emacs/guix-command.el
new file mode 100644
index 0000000000..97a88726df
--- /dev/null
+++ b/emacs/guix-command.el
@@ -0,0 +1,649 @@
+;;; guix-command.el --- Popup interface for guix commands  -*- lexical-binding: t -*-
+
+;; Copyright © 2015 Alex Kost <alezost@gmail.com>
+
+;; This file is part of GNU Guix.
+
+;; GNU Guix is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Guix is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file provides a magit-like popup interface for running guix
+;; commands in Guix REPL.  The entry point is "M-x guix".  When it is
+;; called the first time, "guix --help" output is parsed and
+;; `guix-COMMAND-action' functions are generated for each available guix
+;; COMMAND.  Then a window with these commands is popped up.  When a
+;; particular COMMAND is called, "guix COMMAND --help" output is parsed,
+;; and a user get a new popup window with available options for this
+;; command and so on.
+
+;; To avoid hard-coding all guix options, actions, etc., as much data is
+;; taken from "guix ... --help" outputs as possible.  But this data is
+;; still incomplete: not all long options have short analogs, also
+;; special readers should be used for some options (for example, to
+;; complete package names while prompting for a package).  So after
+;; parsing --help output, the arguments are "improved".  All arguments
+;; (switches, options and actions) are `guix-command-argument'
+;; structures.
+
+;; Only "M-x guix" command is available after this file is loaded.  The
+;; rest commands/actions/popups are generated on the fly only when they
+;; are needed (that's why there is a couple of `eval'-s in this file).
+
+;; COMMANDS argument is used by many functions in this file.  It means a
+;; list of guix commands without "guix" itself, e.g.: ("build"),
+;; ("import" "gnu").  The empty list stands for the plain "guix" without
+;; subcommands.
+
+;; All actions in popup windows are divided into 2 groups:
+;;
+;; - 'Popup' actions - used to pop up another window.  For example, every
+;;   action in the 'guix' or 'guix import' window is a popup action.  They
+;;   are defined by `guix-command-define-popup-action' macro.
+;;
+;; - 'Execute' actions - used to do something with the command line (to
+;;   run a command in Guix REPL or to copy it into kill-ring) constructed
+;;   with the current popup.  They are defined by
+;;   `guix-command-define-execute-action' macro.
+
+;;; Code:
+
+(require 'cl-lib)
+(require 'guix-popup)
+(require 'guix-utils)
+(require 'guix-help-vars)
+(require 'guix-read)
+(require 'guix-base)
+
+(defgroup guix-commands nil
+  "Settings for guix popup windows."
+  :group 'guix)
+
+(defvar guix-command-complex-with-shared-arguments
+  '("system")
+  "List of guix commands which have subcommands with shared options.
+I.e., 'guix foo --help' is the same as 'guix foo bar --help'.")
+
+(defun guix-command-action-name (&optional commands &rest name-parts)
+  "Return name of action function for guix COMMANDS."
+  (guix-command-symbol (append commands name-parts (list "action"))))
+
+
+;;; Command arguments
+
+(cl-defstruct (guix-command-argument
+               (:constructor guix-command-make-argument)
+               (:copier      guix-command-copy-argument))
+  name char doc fun switch? option? action?)
+
+(cl-defun guix-command-modify-argument
+    (argument &key
+              (name    nil name-bound?)
+              (char    nil char-bound?)
+              (doc     nil doc-bound?)
+              (fun     nil fun-bound?)
+              (switch? nil switch?-bound?)
+              (option? nil option?-bound?)
+              (action? nil action?-bound?))
+  "Return a modified version of ARGUMENT."
+  (declare (indent 1))
+  (let ((copy (guix-command-copy-argument argument)))
+    (and name-bound?    (setf (guix-command-argument-name    copy) name))
+    (and char-bound?    (setf (guix-command-argument-char    copy) char))
+    (and doc-bound?     (setf (guix-command-argument-doc     copy) doc))
+    (and fun-bound?     (setf (guix-command-argument-fun     copy) fun))
+    (and switch?-bound? (setf (guix-command-argument-switch? copy) switch?))
+    (and option?-bound? (setf (guix-command-argument-option? copy) option?))
+    (and action?-bound? (setf (guix-command-argument-action? copy) action?))
+    copy))
+
+(defun guix-command-modify-argument-from-alist (argument alist)
+  "Return a modified version of ARGUMENT or nil if it wasn't modified.
+Each assoc from ALIST have a form (NAME . PLIST).  NAME is an
+argument name.  PLIST is a property list of argument parameters
+to be modified."
+  (let* ((name  (guix-command-argument-name argument))
+         (plist (guix-assoc-value alist name)))
+    (when plist
+      (apply #'guix-command-modify-argument
+             argument plist))))
+
+(defmacro guix-command-define-argument-improver (name alist)
+  "Define NAME variable and function to modify an argument from ALIST."
+  (declare (indent 1))
+  `(progn
+     (defvar ,name ,alist)
+     (defun ,name (argument)
+       (guix-command-modify-argument-from-alist argument ,name))))
+
+(guix-command-define-argument-improver
+    guix-command-improve-action-argument
+  '(("graph"       :char ?G)
+    ("environment" :char ?E)
+    ("publish"     :char ?u)
+    ("pull"        :char ?P)
+    ("size"        :char ?z)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-common-argument
+  '(("--help"    :switch? nil)
+    ("--version" :switch? nil)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-target-argument
+  '(("--target" :char ?T)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-system-type-argument
+  '(("--system" :fun guix-read-system-type)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-load-path-argument
+  '(("--load-path" :fun read-directory-name)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-search-paths-argument
+  '(("--search-paths" :char ?P)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-substitute-urls-argument
+  '(("--substitute-urls" :char ?U)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-hash-argument
+  '(("--format" :fun guix-read-hash-format)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-key-policy-argument
+  '(("--key-download" :fun guix-read-key-policy)))
+
+(defvar guix-command-improve-common-build-argument
+  '(("--no-substitutes"  :char ?s)
+    ("--no-build-hook"   :char ?h)
+    ("--max-silent-time" :char ?x)))
+
+(defun guix-command-improve-common-build-argument (argument)
+  (guix-command-modify-argument-from-alist
+   argument
+   (append guix-command-improve-load-path-argument
+           guix-command-improve-substitute-urls-argument
+           guix-command-improve-common-build-argument)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-archive-argument
+  '(("--generate-key" :char ?k)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-build-argument
+  '(("--no-grafts"   :char ?g)
+    ("--root"        :fun guix-read-file-name)
+    ("--sources"     :char ?S :fun guix-read-source-type :switch? nil)
+    ("--with-source" :fun guix-read-file-name)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-environment-argument
+  '(("--exec" :fun read-shell-command)
+    ("--load" :fun guix-read-file-name)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-gc-argument
+  '(("--list-dead" :char ?D)
+    ("--list-live" :char ?L)
+    ("--referrers" :char ?f)
+    ("--verify"    :fun guix-read-verify-options-string)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-graph-argument
+  '(("--type" :fun guix-read-graph-type)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-import-elpa-argument
+  '(("--archive" :fun guix-read-elpa-archive)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-lint-argument
+  '(("--checkers" :fun guix-read-lint-checker-names-string)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-package-argument
+  ;; Unlike all other options, --install/--remove do not have a form
+  ;; '--install=foo,bar' but '--install foo bar' instead, so we need
+  ;; some tweaks.
+  '(("--install"
+     :name "--install " :fun guix-read-package-names-string
+     :switch? nil :option? t)
+    ("--remove"
+     :name "--remove "  :fun guix-read-package-names-string
+     :switch? nil :option? t)
+    ("--install-from-file" :fun guix-read-file-name)
+    ("--manifest"       :fun guix-read-file-name)
+    ("--do-not-upgrade" :char ?U)
+    ("--roll-back"      :char ?R)
+    ("--show"           :char ?w :fun guix-read-package-name)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-refresh-argument
+  '(("--select"     :fun guix-read-refresh-subset)
+    ("--key-server" :char ?S)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-size-argument
+  '(("--map-file" :fun guix-read-file-name)))
+
+(guix-command-define-argument-improver
+    guix-command-improve-system-argument
+  '(("vm-image"    :char ?V)
+    ("--on-error"  :char ?E)
+    ("--no-grub"   :char ?g)
+    ("--full-boot" :char ?b)))
+
+(defvar guix-command-argument-improvers
+  '((()
+     guix-command-improve-action-argument)
+    (("archive")
+     guix-command-improve-common-build-argument
+     guix-command-improve-target-argument
+     guix-command-improve-system-type-argument
+     guix-command-improve-archive-argument)
+    (("build")
+     guix-command-improve-common-build-argument
+     guix-command-improve-target-argument
+     guix-command-improve-system-type-argument
+     guix-command-improve-build-argument)
+    (("download")
+     guix-command-improve-hash-argument)
+    (("hash")
+     guix-command-improve-hash-argument)
+    (("environment")
+     guix-command-improve-common-build-argument
+     guix-command-improve-search-paths-argument
+     guix-command-improve-system-type-argument
+     guix-command-improve-environment-argument)
+    (("gc")
+     guix-command-improve-gc-argument)
+    (("graph")
+     guix-command-improve-graph-argument)
+    (("import" "gnu")
+     guix-command-improve-key-policy-argument)
+    (("import" "elpa")
+     guix-command-improve-import-elpa-argument)
+    (("lint")
+     guix-command-improve-lint-argument)
+    (("package")
+     guix-command-improve-common-build-argument
+     guix-command-improve-search-paths-argument
+     guix-command-improve-package-argument)
+    (("refresh")
+     guix-command-improve-key-policy-argument
+     guix-command-improve-refresh-argument)
+    (("size")
+     guix-command-improve-system-type-argument
+     guix-command-improve-substitute-urls-argument
+     guix-command-improve-size-argument)
+    (("system")
+     guix-command-improve-common-build-argument
+     guix-command-improve-system-argument))
+  "Alist of guix commands and argument improvers for them.")
+
+(defun guix-command-improve-argument (argument improvers)
+  "Return ARGUMENT modified with IMPROVERS."
+  (or (guix-any (lambda (improver)
+                  (funcall improver argument))
+                improvers)
+      argument))
+
+(defun guix-command-improve-arguments (arguments commands)
+  "Return ARGUMENTS for 'guix COMMANDS ...' modified for popup interface."
+  (let ((improvers (cons 'guix-command-improve-common-argument
+                         (guix-assoc-value guix-command-argument-improvers
+                                           commands))))
+    (mapcar (lambda (argument)
+              (guix-command-improve-argument argument improvers))
+            arguments)))
+
+(defun guix-command-parse-arguments (&optional commands)
+  "Return a list of parsed 'guix COMMANDS ...' arguments."
+  (with-temp-buffer
+    (insert (guix-help-string commands))
+    (let (args)
+      (guix-while-search guix-help-parse-option-regexp
+        (let* ((short (match-string-no-properties 1))
+               (name  (match-string-no-properties 2))
+               (arg   (match-string-no-properties 3))
+               (doc   (match-string-no-properties 4))
+               (char  (if short
+                          (elt short 1) ; short option letter
+                        (elt name 2))) ; first letter of the long option
+               ;; If "--foo=bar" or "--foo[=bar]" then it is 'option'.
+               (option? (not (string= "" arg)))
+               ;; If "--foo" or "--foo[=bar]" then it is 'switch'.
+               (switch? (or (string= "" arg)
+                            (eq ?\[ (elt arg 0)))))
+          (push (guix-command-make-argument
+                 :name    name
+                 :char    char
+                 :doc     doc
+                 :switch? switch?
+                 :option? option?)
+                args)))
+      (guix-while-search guix-help-parse-command-regexp
+        (let* ((name (match-string-no-properties 1))
+               (char (elt name 0)))
+          (push (guix-command-make-argument
+                 :name    name
+                 :char    char
+                 :fun     (guix-command-action-name commands name)
+                 :action? t)
+                args)))
+      args)))
+
+(defun guix-command-rest-argument (&optional commands)
+  "Return '--' argument for COMMANDS."
+  (cl-flet ((argument (&rest args)
+              (apply #'guix-command-make-argument
+                     :name "-- " :char ?= :option? t args)))
+    (let ((command (car commands)))
+      (cond
+       ((member command '("archive" "build" "graph" "edit"
+                          "environment" "lint" "refresh"))
+        (argument :doc "Packages" :fun 'guix-read-package-names-string))
+       ((string= command "download")
+        (argument :doc "URL"))
+       ((string= command "gc")
+        (argument :doc "Paths" :fun 'guix-read-file-name))
+       ((member command '("hash" "system"))
+        (argument :doc "File" :fun 'guix-read-file-name))
+       ((string= command "size")
+        (argument :doc "Package" :fun 'guix-read-package-name))
+       ((equal commands '("import" "nix"))
+        (argument :doc "Nixpkgs Attribute"))
+       ;; Other 'guix import' subcommands, but not 'import' itself.
+       ((and (cdr commands)
+             (string= command "import"))
+        (argument :doc "Package name"))))))
+
+(defun guix-command-additional-arguments (&optional commands)
+  "Return additional arguments for COMMANDS."
+  (let ((rest-arg (guix-command-rest-argument commands)))
+    (and rest-arg (list rest-arg))))
+
+;; Ideally only `guix-command-arguments' function should exist with the
+;; contents of `guix-command-all-arguments', but we need to make a
+;; special case for `guix-command-complex-with-shared-arguments' commands.
+
+(defun guix-command-all-arguments (&optional commands)
+  "Return list of all arguments for 'guix COMMANDS ...'."
+  (let ((parsed (guix-command-parse-arguments commands)))
+    (append (guix-command-improve-arguments parsed commands)
+            (guix-command-additional-arguments commands))))
+
+(guix-memoized-defalias guix-command-all-arguments-memoize
+  guix-command-all-arguments)
+
+(defun guix-command-arguments (&optional commands)
+  "Return list of arguments for 'guix COMMANDS ...'."
+  (let ((command (car commands)))
+    (if (member command
+                guix-command-complex-with-shared-arguments)
+        ;; Take actions only for 'guix system', and switches+options for
+        ;; 'guix system foo'.
+        (funcall (if (null (cdr commands))
+                     #'cl-remove-if-not
+                   #'cl-remove-if)
+                 #'guix-command-argument-action?
+                 (guix-command-all-arguments-memoize (list command)))
+      (guix-command-all-arguments commands))))
+
+(defun guix-command-switch->popup-switch (switch)
+  "Return popup switch from command SWITCH argument."
+  (list (guix-command-argument-char switch)
+        (or (guix-command-argument-doc switch)
+            "Unknown")
+        (guix-command-argument-name switch)))
+
+(defun guix-command-option->popup-option (option)
+  "Return popup option from command OPTION argument."
+  (list (guix-command-argument-char option)
+        (or (guix-command-argument-doc option)
+            "Unknown")
+        (let ((name (guix-command-argument-name option)))
+          (if (string-match-p " \\'" name) ; ends with space
+              name
+            (concat name "=")))
+        (or (guix-command-argument-fun option)
+            'read-from-minibuffer)))
+
+(defun guix-command-action->popup-action (action)
+  "Return popup action from command ACTION argument."
+  (list (guix-command-argument-char action)
+        (or (guix-command-argument-doc action)
+            (guix-command-argument-name action)
+            "Unknown")
+        (guix-command-argument-fun action)))
+
+(defun guix-command-sort-arguments (arguments)
+  "Sort ARGUMENTS by name in alphabetical order."
+  (sort arguments
+        (lambda (a1 a2)
+          (let ((name1 (guix-command-argument-name a1))
+                (name2 (guix-command-argument-name a2)))
+            (cond ((null name1) nil)
+                  ((null name2) t)
+                  (t (string< name1 name2)))))))
+
+(defun guix-command-switches (arguments)
+  "Return switches from ARGUMENTS."
+  (cl-remove-if-not #'guix-command-argument-switch? arguments))
+
+(defun guix-command-options (arguments)
+  "Return options from ARGUMENTS."
+  (cl-remove-if-not #'guix-command-argument-option? arguments))
+
+(defun guix-command-actions (arguments)
+  "Return actions from ARGUMENTS."
+  (cl-remove-if-not #'guix-command-argument-action? arguments))
+
+(defun guix-command-post-process-args (args)
+  "Adjust appropriately command line ARGS returned from popup command."
+  ;; XXX We need to split "--install foo bar" and similar strings into
+  ;; lists of strings.  But some commands (e.g., 'guix hash') accept a
+  ;; file name as the 'rest' argument, and as file names may contain
+  ;; spaces, splitting by spaces will break such names.  For example, the
+  ;; following argument: "-- /tmp/file with spaces" will be transformed
+  ;; into the following list: ("--" "/tmp/file" "with" "spaces") instead
+  ;; of the wished ("--" "/tmp/file with spaces").
+  (let* (rest
+         (rx (rx string-start
+                 (or "-- " "--install " "--remove ")))
+         (args (mapcar (lambda (arg)
+                         (if (string-match-p rx arg)
+                             (progn (push (split-string arg) rest)
+                                    nil)
+                           arg))
+                       args)))
+    (if rest
+        (apply #'append (delq nil args) rest)
+      args)))
+
+
+;;; 'Execute' actions
+
+(defvar guix-command-default-execute-arguments
+  (list
+   (guix-command-make-argument
+    :name "repl"  :char ?r :doc "Run in Guix REPL")
+   (guix-command-make-argument
+    :name "shell" :char ?s :doc "Run in shell")
+   (guix-command-make-argument
+    :name "copy"  :char ?c :doc "Copy command line"))
+  "List of default 'execute' action arguments.")
+
+(defvar guix-command-additional-execute-arguments
+  nil
+  "Alist of guix commands and additional 'execute' action arguments.")
+
+(defun guix-command-execute-arguments (commands)
+  "Return a list of 'execute' action arguments for COMMANDS."
+  (mapcar (lambda (arg)
+            (guix-command-modify-argument arg
+              :action? t
+              :fun (guix-command-action-name
+                    commands (guix-command-argument-name arg))))
+          (append guix-command-default-execute-arguments
+                  (guix-assoc-value
+                   guix-command-additional-execute-arguments commands))))
+
+(defvar guix-command-special-executors
+  '((("environment")
+     ("repl" . guix-run-environment-command-in-repl))
+    (("pull")
+     ("repl" . guix-run-pull-command-in-repl)))
+  "Alist of guix commands and alists of special executers for them.
+See also `guix-command-default-executors'.")
+
+(defvar guix-command-default-executors
+  '(("repl"  . guix-run-command-in-repl)
+    ("shell" . guix-run-command-in-shell)
+    ("copy"  . guix-copy-command-as-kill))
+  "Alist of default executers for action names.")
+
+(defun guix-command-executor (commands name)
+  "Return function to run command line arguments for guix COMMANDS."
+  (or (guix-assoc-value guix-command-special-executors commands name)
+      (guix-assoc-value guix-command-default-executors name)))
+
+(defun guix-run-environment-command-in-repl (args)
+  "Run 'guix ARGS ...' environment command in Guix REPL."
+  ;; As 'guix environment' usually tries to run another process, it may
+  ;; be fun but not wise to run this command in Geiser REPL.
+  (when (or (member "--dry-run" args)
+            (member "--search-paths" args)
+            (when (y-or-n-p
+                   (format "'%s' command will spawn an external process.
+Do you really want to execute this command in Geiser REPL? "
+                           (guix-command-string args)))
+              (message "May \"M-x shell-mode\" be with you!")
+              t))
+    (guix-run-command-in-repl args)))
+
+(defun guix-run-pull-command-in-repl (args)
+  "Run 'guix ARGS ...' pull command in Guix REPL.
+Perform pull-specific actions after operation, see
+`guix-after-pull-hook' and `guix-update-after-pull'."
+  (guix-eval-in-repl
+   (apply #'guix-make-guile-expression 'guix-command args)
+   nil 'pull))
+
+
+;;; Generating popups, actions, etc.
+
+(defmacro guix-command-define-popup-action (name &optional commands)
+  "Define NAME function to generate (if needed) and run popup for COMMANDS."
+  (declare (indent 1) (debug t))
+  (let* ((popup-fun (guix-command-symbol `(,@commands "popup")))
+         (doc (format "Call `%s' (generate it if needed)."
+                      popup-fun)))
+    `(defun ,name (&optional arg)
+       ,doc
+       (interactive "P")
+       (unless (fboundp ',popup-fun)
+         (guix-command-generate-popup ',popup-fun ',commands))
+       (,popup-fun arg))))
+
+(defmacro guix-command-define-execute-action (name executor
+                                                   &optional commands)
+  "Define NAME function to execute the current action for guix COMMANDS.
+EXECUTOR function is called with the current command line arguments."
+  (declare (indent 1) (debug t))
+  (let* ((arguments-fun (guix-command-symbol `(,@commands "arguments")))
+         (doc (format "Call `%s' with the current popup arguments."
+                      executor)))
+    `(defun ,name (&rest args)
+       ,doc
+       (interactive (,arguments-fun))
+       (,executor (append ',commands
+                          (guix-command-post-process-args args))))))
+
+(defun guix-command-generate-popup-actions (actions &optional commands)
+  "Generate 'popup' commands from ACTIONS arguments for guix COMMANDS."
+  (dolist (action actions)
+    (let ((fun (guix-command-argument-fun action)))
+      (unless (fboundp fun)
+        (eval `(guix-command-define-popup-action ,fun
+                 ,(append commands
+                          (list (guix-command-argument-name action)))))))))
+
+(defun guix-command-generate-execute-actions (actions &optional commands)
+  "Generate 'execute' commands from ACTIONS arguments for guix COMMANDS."
+  (dolist (action actions)
+    (let ((fun (guix-command-argument-fun action)))
+      (unless (fboundp fun)
+        (eval `(guix-command-define-execute-action ,fun
+                 ,(guix-command-executor
+                   commands (guix-command-argument-name action))
+                 ,commands))))))
+
+(defun guix-command-generate-popup (name &optional commands)
+  "Define NAME popup with 'guix COMMANDS ...' interface."
+  (let* ((command  (car commands))
+         (man-page (concat "guix" (and command (concat "-" command))))
+         (doc      (format "Popup window for '%s' command."
+                           (guix-concat-strings (cons "guix" commands)
+                                                " ")))
+         (args     (guix-command-arguments commands))
+         (switches (guix-command-sort-arguments
+                    (guix-command-switches args)))
+         (options  (guix-command-sort-arguments
+                    (guix-command-options args)))
+         (popup-actions (guix-command-sort-arguments
+                         (guix-command-actions args)))
+         (execute-actions (unless popup-actions
+                            (guix-command-execute-arguments commands)))
+         (actions (or popup-actions execute-actions)))
+    (if popup-actions
+        (guix-command-generate-popup-actions popup-actions commands)
+      (guix-command-generate-execute-actions execute-actions commands))
+    (eval
+     `(guix-define-popup ,name
+        ,doc
+        'guix-commands
+        :man-page ,man-page
+        :switches ',(mapcar #'guix-command-switch->popup-switch switches)
+        :options  ',(mapcar #'guix-command-option->popup-option options)
+        :actions  ',(mapcar #'guix-command-action->popup-action actions)
+        :max-action-columns 4))))
+
+;;;###autoload (autoload 'guix "guix-command" "Popup window for 'guix'." t)
+(guix-command-define-popup-action guix)
+
+
+(defvar guix-command-font-lock-keywords
+  (eval-when-compile
+    `((,(rx "("
+            (group "guix-command-define-"
+                   (or "popup-action"
+                       "execute-action"
+                       "argument-improver"))
+            symbol-end
+            (zero-or-more blank)
+            (zero-or-one
+             (group (one-or-more (or (syntax word) (syntax symbol))))))
+       (1 font-lock-keyword-face)
+       (2 font-lock-function-name-face nil t)))))
+
+(font-lock-add-keywords 'emacs-lisp-mode guix-command-font-lock-keywords)
+
+(provide 'guix-command)
+
+;;; guix-command.el ends here