From a72b7f4b6526a5ceea28b96a679acd2124ba4ca3 Mon Sep 17 00:00:00 2001
From: Javier Sancho <jsf@jsancho.org>
Date: Wed, 5 Jun 2013 15:58:38 +0200
Subject: [PATCH] Structures for managing entities and components, using mutex
 for future synchronization with game loop

* src/gacela.scm: entity
                  get-entity
---
 src/gacela.scm | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/gacela.scm

diff --git a/src/gacela.scm b/src/gacela.scm
new file mode 100644
index 0000000..7fb242f
--- /dev/null
+++ b/src/gacela.scm
@@ -0,0 +1,61 @@
+;;; Gacela, a GNU Guile extension for fast games development
+;;; Copyright (C) 2013 by Javier Sancho Fernandez <jsf at jsancho dot org>
+;;;
+;;; This program 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.
+;;;
+;;; This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+(define-module (gacela gacela)
+  #:use-module (gacela system)
+  #:use-module (ice-9 threads)
+  #:use-module (srfi srfi-1))
+
+
+;;; Entities and components
+
+(define entities-mutex (make-mutex))
+(define game-entities '())
+(define game-components '())
+
+
+(define (entity . components)
+  (with-mutex entities-mutex
+   (let ((key (gensym)))
+     (set! game-entities
+	   (acons key
+		  (map (lambda (c) (list (get-component-type c) c)) components)
+		  game-entities))
+     (set! game-components (register-components key components))
+     key)))
+
+
+(define* (register-components entity components #:optional (clist game-components))
+  (cond ((null? components) clist)
+	(else
+	 (let* ((type (get-component-type (car components)))
+		(elist (assoc-ref clist type)))
+	   (register-components entity (cdr components)
+	     (assoc-set! clist type
+	       (cond (elist
+		      (lset-adjoin eq? elist entity))
+		     (else
+		      (list entity)))))))))
+
+
+(define (get-entity key)
+  (with-mutex entities-mutex
+   (assoc key game-entities)))
+
+
+(export entity
+	get-entity)
-- 
2.39.2