home: Add home-environment.

* gnu/home.scm
(home-environment, home-environment?, this-home-environment)
(home-environment-derivation, home-environment-user-services)
(home-environment-essential-services, home-environment-services)
(home-environment-location, home-environment-with-provenance): New variables.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add home.scm.

Signed-off-by: Oleg Pykhalov <go.wigust@gmail.com>

gnu/home.scm

@@ -0,0 +1,98 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2021 Andrew Tropin <andrew@trop.in>
+;;;
+;;; 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 GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu home)
+  #:use-module (gnu home-services)
+  #:use-module (gnu home-services symlink-manager)
+  #:use-module (gnu home-services shells)
+  #:use-module (gnu home-services xdg)
+  #:use-module (gnu home-services fontutils)
+  #:use-module (gnu services)
+  #:use-module (guix records)
+  #:use-module (guix diagnostics)
+
+  #:export (home-environment
+            home-environment?
+            this-home-environment
+
+            home-environment-derivation
+            home-environment-user-services
+            home-environment-essential-services
+            home-environment-services
+            home-environment-location
+
+            home-environment-with-provenance))
+
+(define-record-type* <home-environment> home-environment
+  make-home-environment
+  home-environment?
+  this-home-environment
+
+  (packages           home-environment-packages            ; list of (PACKAGE OUTPUT...)
+                      (default '()))
+
+  (essential-services home-environment-essential-services  ; list of services
+                      (thunked)
+                      (default (home-environment-default-essential-services
+                                this-home-environment)))
+
+  (services           home-environment-user-services
+                      (default '()))
+
+  (location           home-environment-location            ; <location>
+                      (default (and=> (current-source-location)
+                                      source-properties->location))
+                      (innate)))
+
+(define (home-environment-default-essential-services he)
+  "Return the list of essential services for home environment."
+  (list
+   (service home-run-on-first-login-service-type)
+   (service home-activation-service-type)
+   (service home-environment-variables-service-type)
+
+   (service home-symlink-manager-service-type)
+
+   (service home-fontconfig-service-type)
+   (service home-xdg-base-directories-service-type)
+   (service home-shell-profile-service-type)
+
+   (service home-service-type)
+   (service home-profile-service-type (home-environment-packages he))))
+
+(define* (home-environment-services he)
+  "Return all the services of home environment."
+  (instantiate-missing-services
+   (append (home-environment-user-services he)
+           (home-environment-essential-services he))))
+
+(define* (home-environment-derivation he)
+  "Return a derivation that builds OS."
+  (let* ((services         (home-environment-services he))
+         (home (fold-services services
+                              #:target-type home-service-type)))
+    (service-value home)))
+
+(define* (home-environment-with-provenance he config-file)
+  "Return a variant of HE that stores its own provenance information,
+including CONFIG-FILE, if available.  This is achieved by adding an instance
+of HOME-PROVENANCE-SERVICE-TYPE to its services."
+  (home-environment
+    (inherit he)
+    (services (cons (service home-provenance-service-type config-file)
+                    (home-environment-user-services he)))))

gnu/local.mk

@@ -73,6 +73,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/bootloader/u-boot.scm                     \
   %D%/bootloader/depthcharge.scm                \
   %D%/ci.scm					\
+  %D%/home.scm                                  \
   %D%/home-services.scm                         \
   %D%/home-services/symlink-manager.scm         \
   %D%/home-services/fontutils.scm               \