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.

1 files changed, 22 insertions, 0 deletions

diff --git a/doc/emacs.texi b/doc/emacs.texi
index e72a386303..8020e0ace3 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.
+* Licenses: Emacs Licenses.		Interface for licenses of Guix packages.
 * Popup Interface: Emacs Popup Interface.	Magit-like interface for guix commands.
 * Prettify Mode: Emacs Prettify.	Abbreviating @file{/gnu/store/@dots{}} file names.
 * Build Log Mode: Emacs Build Log.	Highlighting Guix build logs.
@@ -520,6 +521,27 @@ Various settings for ``info'' buffers.
 @end table
 
 
+@node Emacs Licenses
+@section Licenses
+
+If you want to browse the URL of a particular license, or to look at a
+list of licenses, you may use the following commands:
+
+@table @kbd
+
+@item M-x guix-browse-license-url
+Choose a license from a completion list to browse its URL using
+@code{browse-url} function (@pxref{Browse-URL,,, emacs, The GNU Emacs
+Manual}).
+
+@item M-x guix-licenses
+Display a list of available licenses.  You can press @kbd{@key{RET}}
+there to display packages with this license in the same way as @kbd{M-x
+guix-packages-by-license} would do (@pxref{Emacs Commands}).
+
+@end table
+
+
 @node Emacs Popup Interface
 @section Popup Interface