emacs: Gracefully handle wrong package names passed to 'guix-edit'.

Fixes <http://bugs.gnu.org/22933>.

* emacs/guix-main.scm (package-location-string): Rewrite to handle the
case where 'packages-by-name' returns the empty list.

Co-authored-by: Mathieu Lirzin <mthl@gnu.org>

emacs: Use '@' to separate package names and version numbers.

This is a followup to commit 1b846da8c372bee78851439fd9e72b2499115e5a.

* emacs/guix-base.el (guix-package-name-specification): Use "@" instead
of "-".
* emacs/guix-main.scm (name+version->full-name): Likewise.
(package-inputs-names): Use 'make-package-specification' instead of
'package-full-name'.
(full-name->name+version): Update the docstring.
* emacs/guix-ui-package.el (guix-packages-by-name): Likewise.

emacs: hydra: Use '-' to separate job names and version numbers.

* emacs/guix-hydra.el (guix-hydra-job-name-specification): New procedure.
* emacs/guix-ui-package.el (guix-package-info-insert-systems)
(guix-package-list-latest-builds): Use it.

Do not check package freshness during upgrade.

Fixes <http://bugs.gnu.org/22740>.
Reported by Andreas Enge <andreas@enge.fr>.

* gnu/packages.scm (waiting, ftp-open*, check-package-freshness): Remove.
* guix/scripts/package.scm (options->installable): Adjust accordingly.
* emacs/guix-main.scm (package->manifest-entry*): Likewise.

emacs: Do not allow a user to modify system profiles.

Fixes <http://bugs.gnu.org/22607>.
Reported by myglc2 <myglc2@gmail.com>.

Remove possibilities to install/delete packages to/from a system profile
both for "Package List" and "Package Info" buffers.

* emacs/guix-profiles.el (guix-system-profile-regexp): New variable.
(guix-system-profile?): New procedure.
* emacs/guix-ui-package.el (guix-package-info-insert-output): Do not
display "Install"/"Delete" button for a system profile.
(guix-package-assert-non-system-profile): New procedure.
(guix-package-execute-actions): Use it.

emacs: Set 'guix-buffer-item' before displaying entries.

* emacs/guix-buffer.el (guix-buffer-set): Set 'guix-buffer-item' early,
  so that it can be used during displaying entries.  For example, this
  allows us to use a value of the current guix profile when package
  entries are inserted in a "List" or "Info" buffer.

emacs: Add 'M-x guix-installed-{user/system}-packages'.

* emacs/guix-ui-package.el (guix-installed-user-packages)
(guix-installed-system-packages): New commands.
* doc/emacs.texi (Emacs Commands): Document them.

emacs: Autoload hooks instead of putting them in 'guix-init'.

* emacs/guix-init.el: Move adding hooks to...
* emacs/guix-build-log.el: ... here.
* emacs/guix-devel.el: ... and here.

emacs: 'C-u M-x guix-edit' prompts for directory.

* emacs/guix-base.el (guix-read-directory): New procedure.
(guix-find-location, guix-edit): Add optional 'directory' argument.
* emacs/guix-ui-package.el (guix-package-list-edit)
(guix-output-list-edit): Likewise.
* doc/emacs.texi (Emacs Commands): Mention "C-u".

emacs: Find Emacs packages in a system profile.

Fixes <http://bugs.gnu.org/22550>.
Reported by myglc2 <myglc2@gmail.com>.

* emacs/guix-emacs.el (guix-emacs-autoload-packages): Autoload Emacs
  packages installed in a system profile.

emacs: Move the code to load Emacs packages after installing.

This code should belong to "guix-backend" as it is run after a REPL
operation to check if new Emacs packages have been installed and to
autoload them if needed.

* emacs/guix-emacs.el (guix-emacs-activate-after-operation)
(guix-emacs-load-autoloads-maybe): Move and rename to...
* emacs/guix-backend.el (guix-emacs-activate-after-operation)
(guix-repl-autoload-emacs-packages-maybe): ... this.
(guix-after-repl-operation-hook): Adjust for the renaming.

emacs: Factorize searching for Emacs packages.

* emacs/guix-emacs.el: (guix-emacs-directories): New procedure.
(guix-emacs-find-autoloads-in-directory): Rename to...
(guix-emacs-find-autoloads): ... this.
(guix-emacs-load-autoloads): Remove.  Replace with...
(guix-emacs-autoload-packages): ... this.  New procedure.  At first,
find a list of directories with Emacs packages, then add them to
'load-path' and finally, load autoloads.
* doc/emacs.texi (Emacs Initial Setup): Adjust accordingly.

emacs: Add missing (require 'guix-profiles).

Reported by Christopher Allan Webber <cwebber@dustycloud.org> on #guix.

Several modules use the code from 'guix-profiles' without requiring it.  It
was never noticed before commits e4e2154644ecf76ea02a50304c1405c00c9ffdd1
and 13fe4891fa247d306e203ee14c6886513bd86b52, because 'guix-emacs' required
this module.  But now, when 'site-start.el' loads 'guix-emacs',
'guix-profiles' may not exist yet, so it may not be required.  This will
lead to an error when some of "M-x guix-..." commands will be used.  See
<https://gnunet.org/bot/log/guix/2016-02-03#T898859>.

* emacs/guix-base.el: Require 'guix-profiles'.
* emacs/guix-ui.el: Likewise.
* emacs/guix-ui-generation.el: Likewise.
* emacs/guix-ui-package.el: Likewise.

emacs: command: Disambiguate "w" key in build options.

This is a followup to commit 47c0f92c37dc7d50d9d4598ce5b91c4cdfec6ed1.

* emacs/guix-command.el (guix-command-improve-common-build-argument):
  Use "W" key for '--with-input' option (leave "w" for '--with-source').

guix system: Rename 'dmd-graph' to 'shepherd-graph'.

* doc/images/dmd-graph.dot: Rename to...
* doc/images/shepherd-graph.dot: ... this.
* doc.am (DOT_FILES): Adjust accordingly.
* guix/scripts/system.scm (dmd-service-node-label)
  (dmd-service-node-type, export-dmd-graph): Rename to...
  (shepherd-service-node-label, shepherd-service-node-type)
  (export-shepherd-graph): ... this.
  (show-help, process-action, process-command): Rename 'dmd-graph' to
  'shepherd-graph'.
* emacs/guix-command.el (guix-command-additional-execute-arguments)
  (guix-command-special-executors): Likewise.
* doc/guix.texi: Likewise.
* doc/emacs.texi (Emacs Popup Interface): Likewise.

emacs: Add interface for licenses.

* emacs/guix-main.scm (%license-param-alist): New variable.
  (license->sexp, find-licenses, license-entries): New procedures.
* emacs/guix-license.el (guix-license-get-entries)
  (guix-license-get-display, guix-license-insert-packages-button)
  (guix-license-insert-comment, guix-license-list-describe)
  (guix-license-list-show-packages): New procedures.
  (guix-licenses): New command.
* doc/emacs.texi (Emacs Licenses): New node.
  (Emacs Interface): Add it.
* doc/guix.texi (Top): Add it.
* NEWS: Mention new interface.

emacs: list: Support displaying URL links.

* emacs/guix-list.el (guix-list-url): New face.
  (guix-list-get-url): New procedure.

emacs: Add 'guix-packages-by-license' command.

* emacs/guix-main.scm (packages-by-license): New procedure.
(%patterns-makers): Add 'license' search type.
* emacs/guix-messages.el (guix-message-packages-by-license): New procedure.
(guix-messages): Use it.
* emacs/guix-ui-package.el (guix-packages-by-license): New command.
* doc/emacs.texi (Emacs Commands): Document it.

emacs: Buttonize licenses in "Package Info".

* emacs/guix-ui-package.el (guix-package-license): New button type.
  (guix-package-info-format, guix-output-info-format): Use it.
* doc/emacs.texi (Emacs Info buffer): Mention it.

emacs: Add 'guix-browse-license-url' command.

* emacs/guix-main.scm (%licenses): New variable.
(licenses, license-names, lookup-license, lookup-license-uri): New
procedures.
* emacs/guix-read.el (guix-license-names, guix-read-license-name): New
procedures.
* emacs/guix-license.el: New file.
(guix-lookup-license-url): New procedure.
(guix-browse-license-url): New command.
* emacs.am (ELFILES): Add new file.