services: Add 'system-service-type'.

* gnu/services.scm (system-derivation): New procedure.
  (system-service-type): New variable.
  (boot-script-entry): New procedure.
  (boot-service-type): Extend SYSTEM-SERVICE-TYPE.
  (etc-entry): New procedure.
  (etc-service-type): Extend SYSTEM-SERVICE-TYPE.
  (fold-services): Change default #:target-type to SYSTEM-SERVICE-TYPE.
* gnu/system.scm (operating-system-directory-base-entries): New procedure.
  (essential-services): Use it.  Add an instance of
  SYSTEM-SERVICE-TYPE.
  (operating-system-boot-script): Pass #:target-type to 'fold-services'.
  (operating-system-derivation): Rewrite in terms of 'fold-services'.
* gnu/system/linux-container.scm (system-container): Remove.
  (container-script): Use 'operating-system-derivation'.
* guix/scripts/system.scm (export-extension-graph): Replace
  BOOT-SERVICE-TYPE by SYSTEM-SERVICE-TYPE.
* doc/images/service-graph.dot: Add 'system' node and edges.
* doc/guix.texi (Service Composition): Mention SYSTEM-SERVICE-TYPE.
  (Service Reference): Document it.  Update 'fold-services'
  documentation.

scripts: environment: Ignore user shell when spawning container.

* guix/scripts/environment.scm (%default-options): Remove 'exec'
  association.
  (guix-environment): If the user didn't specify a command, use the
  default shell, or use /bin/sh when a container is requested.

emacs: Add completions for '--type' option of 'refresh' popup.

* guix/scripts/refresh.scm: Export '%updaters'.
* emacs/guix-main.scm (refresh-updater-names): New procedure.
* emacs/guix-base.el (guix-refresh-updater-names): New function.
* emacs/guix-read.el (guix-read-refresh-updater-names,
  guix-read-refresh-updater-names-string): New functions.
* emacs/guix-command.el (guix-command-improve-refresh-argument): Use
  'guix-read-refresh-updater-names-string'.

scripts: Add 'container' subcommand.

* guix/scripts/container.scm: New file.
* guix/scripts/container/exec.scm: New file.
* po/guix/POTFILES.in: Add them.
* Makefile.am (MODULES): Add them.
* doc/guix.texi (Invoking guix container): New section.

guix system: Fix typo in --help message.

* guix/scripts/system.scm (show-help): Align 'container' the same way as
  other actions.

scripts: environment: Allow lists of packages in expressions.

* guix/scripts/environment.scm (options/resolve-packages): Match against
  lists of packages when evaluating expressions.
* tests/guix-environment.sh: Add test.
* doc/guix.texi ("invoking guix environment"): Add docs.

scripts: system: Add 'container' action.

* guix/scripts/system.scm (show-help): Display 'container' action.
  (system-derivation-for-action, guix-system): Add 'container' case.
  (perform-action): Skip GRUB config generation when building a container.
* doc/guix.texi (Invoking guix system): Document it.

Merge branch 'master' into dbus-update

scripts: environment: Allow mixing regular and ad-hoc packages.

This patch changes the --ad-hoc flag to be positional.  That is, the
packages that appear before --ad-hoc are interpreted as packages whose
inputs should be in the environment; the packages that appear after are
interpreted as packages to be directly added to the environment.

* guix/scripts/environment.scm (tag-package-arg, compact): New
  procedures.
  (%options): Tweak the handlers for --load and --expression options.
  (options/resolve-packages): Preserve package mode tag.
  (parse-args): Tweak argument handler to use package tagging procedure.
  (guix-environment): Apply ad-hoc behavior on a per package basis.
* tests/guix-environment.sh: Add test.
* doc/guix.texi ("invoking guix environment"): Document new behavior of
  --ad-hoc.

refresh: Support comma-separated updater types.

* guix/scripts/refresh.scm (%options): Handle comma-separated types for
  '--type' option.
  (guix-refresh): Adjust accordingly.
  (show-help): Likewise.
* doc/guix.texi (Invoking guix refresh): Document it.

ui: Add 'make-regexp*'.

Fixes <http://bugs.gnu.org/21773>.
Reported by Jan Synáček <jan.synacek@gmail.com>.

* guix/ui.scm (make-regexp*): New procedure.
* guix/scripts/package.scm (options->installable, guix-package): Use it
  when processing user-provided regexps.

store: Use the daemon's substitute URLs by default.

Partly fixes <http://bugs.gnu.org/20217>.

* guix/store.scm (set-build-options): Change #:substitute-urls to
  default to #f.  Send the 'substitute-urls' pair only if
  SUBSTITUTE-URLS is true.
* guix/scripts/build.scm (set-build-options-from-command-line): Do not
  default to %DEFAULT-SUBSTITUTE-URLS for #:substitute-urls.
* guix/scripts/size.scm (%default-options): Remove 'substitute-urls'.

scripts: build: Add --file option.

* guix/scripts/build.scm (show-help): Add help text for --file option.
  (%options): Add --file option.
  (options/resolve-packages): Handle 'file' options.
* tests/guix-build.sh: Add tests.
* doc/guix.texi ("invoking guix build"): Add doc.

substitute: Honor all the specified server URLs.

* guix/scripts/substitute.scm (lookup-narinfos/diverse): New procedure.
  (lookup-narinfo): Use it.
  (process-query): Change #:cache-url to #:cache-urls.
  [valid?]: Remove 'narinfo?' check, which is no longer necessary.
  Use 'lookup-narinfos/diverse' instead of 'lookup-narinfos'.
  (process-substitution): Change #:cache-url to #:cache-urls.
  (%cache-url): Rename to...
  (%cache-urls): ... this.  Turn into a list.
  (guix-substitute): Remove 'getaddrinfo' test with early exit.  Adjust
  calls to 'process-query' and 'process-substitution'.
* tests/substitute.scm: Change '%cache-url' to '%cache-urls'.

substitute: 'lookup-narinfos' returns exactly a list of narinfos.

* guix/scripts/substitute.scm (lookup-narinfos): Filter out #f values
  from CACHED, such that the end result is exactly a list of narinfos,
  not interspersed with #f.
* guix/scripts/challenge.scm (discrepancies): Assume REMOTE is a list of
  narinfos.

substitute: 'http-multiple-get' follows 'fold' style.

* guix/scripts/substitute.scm (http-multiple-get): Add 'seed'
  parameter.  Call PROC in 'fold' style.
  (fetch-narinfos)[handle-narinfo-response]: Adjust accordingly.
  Update 'http-multiple-get' call accordingly.

refresh: Add '--list-updaters' option.

* guix/scripts/refresh.scm (list-updaters-and-exit): New procedure.
  (%options, show-help): Add '--list-updaters' option.
* doc/guix.texi (Invoking guix refresh): Document it.

profiles: Add generation manipulation procedures.

* guix/scripts/package.scm (delete-generations): Use
  'delete-generation*' instead of 'delete-generation'.
  (guix-package)[process-actions]: Use 'roll-back*' instead of
  'roll-back' and 'switch-to-generation*' instead of
  'switch-to-generation'.
  (link-to-empty-profile, switch-to-generation,
  switch-to-previous-generation, roll-back, delete-generation): Move
  to...
* guix/profiles.scm: ... here.  Adjust to not print messages and to
  return values that can be used by user interfaces.
* guix/ui.scm (display-generation-change, roll-back*,
  switch-to-generation*, delete-generation*): New procedures.

utils: Add 'switch-symlinks', moved from (guix ui).

* guix/ui.scm (switch-symlinks): Move to...
* guix/utils.scm: ... here.  New procedure.
* guix/scripts/pull.scm: Use it.

guix system: Add the 'list-generations' command.

* guix/scripts/system.scm (display-system-generation, list-generations):
  New procedures.
  (process-action): Clarify docstring.
  (process-command): New procedure.
  (guix-system)[parse-sub-command]: Add 'list-generations'
  Call 'process-command' instead of 'process-action'.
* doc/guix.texi (Using the Configuration System): Mention generations,
  rollback, and 'list-generations'.
  (Invoking guix system): Document 'list-generations'.