METALICENSE

Copyright (C) 2009-2024, Kaz Kylheku <kaz@kylheku.com>.
All rights reserved.

The document named LICENSE specifies the license for the TXR program,
including the library modules which it it uses, most of which are likewise
BSD licensed.

The MPI library, found in the mpi/ subdirectory, was developed over
the years 1998-2006 by Michael J. Fromberger. Its license consists
of the mpi/README file, which states:

   This software is in the public domain.  It is entirely free, and you
   may use it and/or redistribute it for whatever purpose you choose;
   however, as free software, it is provided without warranty of any
   kind, not even the implied warranty of merchantability or fitness for
   a particular purpose.

Whether or not software can be explicitly deposited into the public domain is
controversial, so the MPI library may have to be regarded as being copyrighted
by Michael J. Fromberger. The above text can be reasonably understood to
constitute a license grant which is compatible with TXR's Two-Clause BSD
license in the sense that it is at least as permissive.

The RSA-derived MD5 digest routines are used in in accordance with the
permission granted by a February 23, 2000 memo from John Linn
<jlinn@rsasecurity.com> to the IETF. License-like wording from this memo
has been placed by the TXR project into block comments of the md5.c
and md5.h files. The permission is compatible with the BSD license,
as it allows unfettered redistribution and use, without any advertizing
clauses.

SHA-1 routines used in TXR are derived from code written by Jun-ichiro Itoh
in the 1990s.  Their copyright notice attributes them to the WIDE project,
and licenses them under a three-clause BSD license.

SHA-256 routines used in TXR are derived from code which is
Copyright 2005 Colin Percival, and available under the same two-clause
BSD license as TXR.

TXR ships with files (y.tab.c, y.tab.h) generated from the file parser.y using
GNU Bison. The source file parser.y is the original work of Kaz Kylheku, and
licensed under the same terms as the rest of TXR. The generated files contain
all of that material, plus material coming from Bison. The material coming from
Bison is owned by the Free Software Foundation, distributed under the GPLv3
license, with a special "Bison exception" which allows unrestricted,
unencumbered redistribution in source or compiled form, similar to the BSD
license. That special exception lapses if the material is borrowed for creating
a parser skeleton for a parser generator program (analogous to Bison). In such
a situation, the GPLv3 license comes into full force. TXR readily complies with
this condition; therefore, those two files are compatible with TXR's BSD
license, and may be redistributed as part of TXR.

TXR is ported to Windows with the help of a derivative of the Cygwin library.
For user convenience, a packaged version of TXR includes the CYGWIN1.DLL, in
accordance with the terms of Cygwin's license, the GNU Lesser Public License,
Version 3.  More details are in the document LICENSE-CYG, which is incorporated
into the Windows installer and displayed to users during installation to inform
them of the dependency on a LGPL-ed library.