gnu: Add reuse.

* gnu/packages/license.scm (reuse): New public variable.

gnu/packages/license.scm

@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2018 Oleg Pykhalov <go.wigust@gmail.com>
-;;; Copyright © 2018 Tobias Geerinckx-Rice <me@tobias.gr>
+;;; Copyright © 2018, 2019 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -19,10 +19,15 @@
 
 (define-module (gnu packages license)
   #:use-module (gnu packages)
+  #:use-module (gnu packages check)
   #:use-module (gnu packages perl)
   #:use-module (gnu packages perl-check)
+  #:use-module (gnu packages python-web)
+  #:use-module (gnu packages python-xyz)
   #:use-module (guix build-system perl)
+  #:use-module (guix build-system python)
   #:use-module (guix download)
+  #:use-module (guix git-download)
   #:use-module (guix licenses)
   #:use-module (guix packages))
 
@@ -160,3 +165,45 @@ statements and serializes in normalized format.")
 to each file passed to it, by searching the start of the file for text
 belonging to various licenses.")
     (license (package-license perl))))
+
+(define-public reuse
+  (package
+    (name "reuse")
+    (version "0.5.0")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://git.fsfe.org/reuse/tool.git")
+             (commit (string-append "v" version))))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "1w17g6jvs715rjc93nnnqnfdphijq4ymj9jjkr3ccc286ywvn3ih"))))
+    (build-system python-build-system)
+    (native-inputs
+     `(("python-pytest" ,python-pytest)))
+    (inputs
+     `(("python-binaryornot" ,python-binaryornot)
+       ("python-boolean.py" ,python-boolean.py)
+       ("python-debian" ,python-debian)
+       ("python-jinja2" ,python-jinja2)
+       ("python-license-expression" ,python-license-expression)
+       ("python-requests" ,python-requests)))
+    (home-page "https://reuse.software/")
+    (synopsis "Provide and verify copyright and licensing information")
+    (description
+     "The REUSE tool helps you achieve and confirm license compliance with the
+@uref{https://reuse.software, REUSE specification}, a set of recommendations
+for licensing Free Software projects.  REUSE makes it easy to declare the
+licenses under which your works are released, especially when reusing software
+from different projects released under different licenses.  It avoids reliance
+on fuzzy heuristicts and allows both legal experts and computers to understand
+how your project is licensed.  This allows generating a \"bill of materials\"
+for software.
+
+This tool downloads full license texts, adds copyright and license information
+to file headers, and contains a linter to identify problems.  There are other
+tools that have a lot more features and functionality surrounding the analysis
+and inspection of copyright and licenses in software projects.  This one is
+designed to be simple.")
+    (license (list asl2.0 gpl3+))))