gnu: Add yml2.

* gnu/packages/pep.scm: New file.
* gnu/locak.mk (GNU_SYSTEM_MODULES): Add it.

gnu/local.mk

@@ -413,6 +413,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/packages/pcre.scm				\
   %D%/packages/pdf.scm				\
   %D%/packages/pem.scm				\
+  %D%/packages/pep.scm				\
   %D%/packages/perl.scm				\
   %D%/packages/perl-check.scm			\
   %D%/packages/perl-compression.scm		\

gnu/packages/pep.scm

@@ -0,0 +1,49 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2016, 2020 Hartmut Goebel <h.goebel@crazy-compilers.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu packages pep)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix packages)
+  #:use-module (guix hg-download)
+  #:use-module (guix build-system python)
+  #:use-module (gnu packages)
+  #:use-module (gnu packages xml))
+
+(define-public yml2
+  (package
+    (name "yml2")
+    (version "2.6.3")
+    (source (origin
+       (method hg-fetch)
+       (uri (hg-reference
+             (url "https://pep.foundation/dev/repos/yml2")
+             (changeset version)))
+       (file-name (string-append name "-" version "-checkout"))
+       (sha256
+        (base32 "10jjjyq1mz18zkzvxd62aba00h69gd9cglisqcvb81j67ml2v1bx"))))
+    (build-system python-build-system)
+    (propagated-inputs
+     `(("python-lxml" ,python-lxml)))
+    (home-page "https://fdik.org/yml/")
+    (synopsis "Use a Domain Specific Language for XML without defining
+a grammar")
+    (description "The YML compiler is a small Python script.  It
+provides the command line front end yml2c.  As default, it compiles
+your script and outputs to stdout, that usually is the terminal.  Your
+shell provides options to redirect the output into a pipe or a file.")
+    (license license:gpl2)))