* gnu/services/xorg.scm (slim-service): Document session types and
  ~/.xsession.
* doc/guix.texi (X Window): Adjust accordingly.

* gnu/services/desktop.scm (%desktop-services): New variable.
* doc/guix.texi (Desktop Services): Document it.

* gnu/system/nss.scm (%mdns-host-lookup-nss): New variable.
* doc/guix.texi (Name Service Switch): Document it.

* gnu/services/databases.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi ("Database Services"): New subsubsection.

Suggested by 宋文武 <iyzsong@gmail.com>
in <http://bugs.gnu.org/20255>.

* guix/build/profiles.scm (abstract-profile,
  write-environment-variable-definition): New procedures.
  (build-profile): Add #:search-paths parameter.  Create
  OUTPUT/etc/profile.
* guix/profiles.scm (profile-derivation)[builder]: Add 'search-paths'
  variable and pass it to 'build-profile'.  Adjust #:modules argument.
* tests/profiles.scm ("etc/profile"): New test.
* doc/guix.texi (Invoking guix package): Mention etc/profile.

* gnu/services/colord.scm, gnu/services/dbus.scm,
  gnu/services/upower.scm: Remove.
* gnu/services/desktop.scm: New file, with contents taken from the above
  files.
* gnu-system.am (GNU_SYSTEM_MODULES): Adjust accordingly.
* doc/guix.texi (Desktop Services): New section.
  (Various Services): Move colord-service and upower-service from
  here to "Desktop Services".

Reported by Christopher A. Webber <cwebber@dustycloud.org>.

* doc/guix.texi (The Store Monad): Reintroduce 'mlet' in 'sh-symlink'
  example.  Move the simplified version below.  Explain that the 'store'
  parameter is threaded.

* doc/guix.texi (Build Environment Setup): Use 'groupadd --system'.

* doc/guix.texi (Binary Installation): Specifically refer to
  group/account creation, and add an item for substitutes.  Mention
  verifiability.

* doc/guix.texi (The Store Monad): Replace reference to "profile.sh",
  which is not defined until the next node, with "sh-symlink", which
  is defined immediately above

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

* guix/scripts/build.scm (%options, options->derivations): Add --sources
  option.
* doc/guix.texi (Invoking guix build): Document --sources option.
* tests/guix-build.sh: Add tests.

* gnu/services/base.scm (console-keymap-service): New procedure.
* doc/guix.texi (Base Services): Document it.

Co-authored-by: 宋文武 <iyzsong@gmail.com>

Suggested by Joshua Randall <jcrandall@alum.mit.edu>
in <http://bugs.gnu.org/20402>.

* guix/derivations.scm (derivation): Add #:leaked-env-vars parameter.
  [user+system-env-vars]: Honor it.
* guix/gexp.scm (gexp->derivation): Add #:leaked-env-vars and pass it to
  'raw-derivation'.
* doc/guix.texi (Derivations, G-Expressions): Adjust accordingly.

* gnu/system/file-systems.scm (%immutable-store): New variable.
  (%base-file-systems): Add it.
* doc/guix.texi (File Systems): Document it.

* guix/scripts/package.scm (guix-package)[process-query]
  <list-available>: Restrict results to packages matching
  'supported-package?".
* guix/ui.scm (package->recutils): Print "systems:".
* tests/guix-package.sh: Add tests.
* doc/guix.texi (Invoking guix package): Adjust description of
  '--list-available' accordingly.

Suggested by Pjotr Prins <pjotr.public12@thebird.nl>.

* doc/guix.texi (Binary Installation): Move warning about overwriting
  higher up.

* gnu/packages.scm (find-packages-by-name): Sort MATCHING according to
  'version>?'.  Use 'string-prefix?' instead of 'string=?' to compare
  against VERSION.
* doc/guix.texi (Invoking guix package): Add example and explanation.

* guix/scripts/refresh.scm (guix-refresh): Use 'specification->package'
  instead of 'find-packages-by-name'.  This allows users to specify
  things like "qt-4.8.6".
* doc/guix.texi (Invoking guix refresh): Add an example.

* doc/guix.texi (Binary Installation): New section.

* guix/scripts/package.scm (%options): Add the '--do-not-upgrade' option.
  (show-help): Document it.
  (options->installable): Add 'do-not-upgrade-regexps' variable.
  Use it in 'packages-to-upgrade'.
* doc/guix.texi (Invoking guix package): Document the '--do-not-upgrade'
  option.

* gnu-system.am (GNU_SYSTEM_MODULES): Add gnu/services/upower.scm.
* gnu/services/upower.scm: New file, defining a upower service.
* doc/guix.texi (Various Services): Mention it.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

* doc/guix.texi (Name Service Switch): Add link to nss-mdns.  Add
  example show how to pass #:name-services to 'nscd-service'.
  (Base Services): Add link from 'nscd-service' to the above.
* gnu/services/base.scm (nscd-service): Update docstring accordingly.

Fixes <http://bugs.gnu.org/19795>.
Reported by David Thompson <dthompson2@worcester.edu>.

* gnu/build/activation.scm (enumerate, current-users, current-groups,
  delete-user, delete-group): New procedures.
  (activate-users+groups): Add calls to 'delete-user' and
  'delete-group'.
* doc/guix.texi (User Accounts): Add a paragraph about statelessness.
  Explain that passwords are preserved.

* guix/scripts/import.scm (importers): Add hackage.
* guix/scripts/import/hackage.scm: New file.
* po/guix/POTFILES.in: Add guix/scripts/import.scm.
* doc/guix.texi: Add section on 'hackage' importer.

* gnu-system.am (GNU_SYSTEM_MODULES): Add gnu/services/colord.scm.
* gnu/services/colord.scm: New file.
* doc/guix.texi (Various Services): Document it.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

Suggested by Mark H Weaver.

* doc/guix.texi (Setting Up the Daemon): Add xref to "Substitutes".

* doc/guix.texi (Package Modules): Mention the relation between module
  names and file names.

* doc/guix.texi (Invoking guix package): Mention that the current
  generation is not deleted.  This is a followup to d26eb84d.

* guix/scripts/publish.scm: New file.
* po/guix/POTFILES.in: Add it.
* tests/publish.scm: New file.
* Makefile.am (MODULES): Add script module.
  (SCM_TESTS): Add test module.
* doc/guix.texi ("Invoking guix publish"): New node.

* guix/build-system/haskell.scm: New file.
* guix/build/haskell-build-system.scm: New file.
* doc/guix.texi: Add section on 'haskell-build-system'.

* gnu/services/ssh.scm (lsh-service): Change #:initialize? to default
  to #t.
* doc/guix.texi (Using the Configuration System): Remove #:initialize? #t
  from example.
  (Networking Services): Adjust accordingly.

* doc/guix.texi (Invoking guix gc): Add that this is the only way to
  delete files.

* doc/guix.texi (Build Environment Setup): Remove bit about creating
  /gnu/store.  This is done automatically since 15ddeff5.

* gnu/services/base.scm (syslog-service): Add 'config-file' keyword
argument.
* doc/guix.texi (Base Services): Document it.

* guix/gexp.scm (<local-file>): New record type.
  (local-file): New procedure.
  (local-file-compiler): New compiler.
  (gexp->sexp) <struct? thing>: Handle the case where 'lower' returns a
  file name.
  (text-file*): Update docstring.local-file doc
* tests/gexp.scm ("one local file", "gexp->derivation, local-file"): New
  tests.
* doc/guix.texi (G-Expressions): Mention local files early.  Document
  'local-file'.  Update 'text-file*' documentation.

This is a followup to bcb13287.

* doc/guix.texi (G-Expressions): Move paragraph about extensibility
  below.  Remove assumptions that things are either packages or
  derivations.

* gnu/services/lirc.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (Various Services): New node.  Document 'lirc-service'.

* doc/guix.texi (Running the Test Suite): New section.

From now own, (guix packages) depends on (guix gexps); it was the other
way around now.  This means that (guix packages) code can use gexps.

* guix/gexp.scm (origin-compiler, package-compiler): Remove.
  (default-guile-derivation): New procedure.
  (gexp->derivation): Use it instead of 'default-guile' +
  'package->derivation'.
* guix/packages.scm (default-guile-derivation): New procedure.
  (package-compiler, origin-compiler): New variables.
* doc/guix.texi (G-Expressions): Mention extensibility.

* gnu/services/xorg.scm (<session-type>, %windowmaker-session-type)
  (%ratposion-session-type, %sawfish-session-type, %default-xsessions)
  (xsessions-directory): Remove.
  (slim-service): Remove #:sessions parameter.
  [slim.cfg]: Use /run/current-system/profile/share/xsessions as sessiondir.
* doc/guix.texi <X Window>: Adjust accordingly.