[bpt/guile.git] / libguile / guardians.c

/* Copyright (C) 1998,1999,2000,2001, 2006, 2008, 2009, 2011 Free Software Foundation, Inc.
 * 
 * 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
 */

\f
/* This is an implementation of guardians as described in
 * R. Kent Dybvig, Carl Bruggeman, and David Eby (1993) "Guardians in
 * a Generation-Based Garbage Collector" ACM SIGPLAN Conference on
 * Programming Language Design and Implementation, June 1993
 * ftp://ftp.cs.indiana.edu/pub/scheme-repository/doc/pubs/guardians.ps.gz
 *
 * Original design:          Mikael Djurfeldt
 * Original implementation:  Michael Livshin
 * Hacked on since by:       everybody
 *
 * By this point, the semantics are actually quite different from
 * those described in the abovementioned paper.  The semantic changes
 * are there to improve safety and intuitiveness.  The interface is
 * still (mostly) the one described by the paper, however.
 *
 * Boiled down again:        Marius Vollmer
 *
 * Now they should again behave like those described in the paper.
 * Scheme guardians should be simple and friendly, not like the greedy
 * monsters we had...
 *
Commit	Line	Data
393baa8a	1	/* Copyright (C) 1998,1999,2000,2001, 2006, 2008, 2009, 2011 Free Software Foundation, Inc.
e1f2bf99	2	*
73be1d9e	3	* This library is free software; you can redistribute it and/or
53befeb7 NJ	4	* modify it under the terms of the GNU Lesser General Public License
	5	* as published by the Free Software Foundation; either version 3 of
	6	* the License, or (at your option) any later version.
e1f2bf99	7	*
53befeb7 NJ	8	* This library is distributed in the hope that it will be useful, but
53befeb7 NJ	9	* WITHOUT ANY WARRANTY; without even the implied warranty of
73be1d9e MV	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
73be1d9e MV	11	* Lesser General Public License for more details.
e1f2bf99	12	*
73be1d9e MV	13	* You should have received a copy of the GNU Lesser General Public
73be1d9e MV	14	* License along with this library; if not, write to the Free Software
53befeb7 NJ	15	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
53befeb7 NJ	16	* 02110-1301 USA
73be1d9e	17	*/
1bbd0b84	18
e1f2bf99	19	\f
e1f2bf99 MD	20	/* This is an implementation of guardians as described in
	21	* R. Kent Dybvig, Carl Bruggeman, and David Eby (1993) "Guardians in
	22	* a Generation-Based Garbage Collector" ACM SIGPLAN Conference on
	23	* Programming Language Design and Implementation, June 1993
	24	* ftp://ftp.cs.indiana.edu/pub/scheme-repository/doc/pubs/guardians.ps.gz
	25	*
06c1d900 MV	26	* Original design: Mikael Djurfeldt
	27	* Original implementation: Michael Livshin
	28	* Hacked on since by: everybody
	29	*
56495472 ML	30	* By this point, the semantics are actually quite different from
	31	* those described in the abovementioned paper. The semantic changes
	32	* are there to improve safety and intuitiveness. The interface is
	33	* still (mostly) the one described by the paper, however.
	34	*
06c1d900 MV	35	* Boiled down again: Marius Vollmer
	36	*
	37	* Now they should again behave like those described in the paper.
	38	* Scheme guardians should be simple and friendly, not like the greedy
	39	* monsters we had...
bc700b6d	40	*
5aec3cf4	41