--- /dev/null
+;;; -*-scheme-*-
+
+;;; Mes --- Maxwell Equations of Software
+;;; Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;
+;;; This file is part of Mes.
+;;;
+;;; Mes 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.
+;;;
+;;; Mes 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 Mes. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(mes-use-module (mes guile))
+(mes-use-module (mes quasiquote))
+(include-from-path "mes/pmatch.scm")
--- /dev/null
+;;; pmatch, a simple matcher
+
+;;; Copyright (C) 2009, 2010, 2012 Free Software Foundation, Inc
+;;; Copyright (C) 2005,2006,2007 Oleg Kiselyov
+;;; Copyright (C) 2007 Daniel P. Friedman
+;;;
+;;; This library is free software; you can redistribute it and/or
+;;; modify it under the terms of the GNU Lesser General Public
+;;; License as published by the Free Software Foundation; either
+;;; version 3 of the License, or (at your option) any later version.
+;;;
+;;; This library 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
+;;; Lesser General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with this library; if not, write to the Free Software
+;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+;;; Originally written by Oleg Kiselyov for LeanTAP in Kanren, which is
+;;; available under the MIT license.
+;;;
+;;; http://kanren.cvs.sourceforge.net/viewvc/kanren/kanren/mini/leanTAP.scm?view=log
+;;;
+;;; This version taken from:
+;;; αKanren: A Fresh Name in Nominal Logic Programming
+;;; by William E. Byrd and Daniel P. Friedman
+;;; Proceedings of the 2007 Workshop on Scheme and Functional Programming
+;;; Université Laval Technical Report DIUL-RT-0701
+
+;;; To be clear: the original code is MIT-licensed, and the modifications
+;;; made to it by Guile are under Guile's license (currently LGPL v3+).
+
+;;; Code:
+
+(define-module (system base pmatch)
+ #:export-syntax (pmatch))
+
+(define-syntax-rule (pmatch e cs ...)
+ (let ((v e)) (pmatch1 v cs ...)))
+
+(define-syntax pmatch1
+ (syntax-rules (else guard)
+ ((_ v) (if #f #f))
+ ((_ v (else e0 e ...)) (let () e0 e ...))
+ ((_ v (pat (guard g ...) e0 e ...) cs ...)
+ (let ((fk (lambda () (pmatch1 v cs ...))))
+ (ppat v pat
+ (if (and g ...) (let () e0 e ...) (fk))
+ (fk))))
+ ((_ v (pat e0 e ...) cs ...)
+ (let ((fk (lambda () (pmatch1 v cs ...))))
+ (ppat v pat (let () e0 e ...) (fk))))))
+
+(define-syntax ppat
+ (syntax-rules (_ quote unquote)
+ ((_ v _ kt kf) kt)
+ ((_ v () kt kf) (if (null? v) kt kf))
+ ((_ v (quote lit) kt kf)
+ (if (equal? v (quote lit)) kt kf))
+ ((_ v (unquote var) kt kf) (let ((var v)) kt))
+ ((_ v (x . y) kt kf)
+ (if (pair? v)
+ (let ((vx (car v)) (vy (cdr v)))
+ (ppat vx x (ppat vy y kt kf) kf))
+ kf))
+ ((_ v lit kt kf) (if (eq? v (quote lit)) kt kf))))