/*
**
** Eval.c      A floating point expression evaluator.
**             Main source module.
**
** v1.18   7-11-05
**         Fixed bug where the constant list wasn't quite in alphabetic
**         order and this caused the value of _qe to be incorrectly
**         reported as unassigned.
**
** v1.17   4-27-05
**         Modified so that unary operators do not take precedence over
**         the power operator (^), so that -2^2 = -4 rather than 4.
**         This makes Eval more consistent with C and FORTRAN precedence
**         rules.
**
** v1.16   9-7-04    *Added colon as command separator and check
**                   *EVAL_STARTUP environment variable.
**                   *Updated constants with 2002 CODATA
**                    (http://physics.nist.gov/constants/)
**         Known bug:  The colon separator doesn't work immediately
**                     after "Press <ENTER> for more..."
**
** v1.15   11-7-03   Added an icon to the Win32 version.
**
** v1.14   3-5-99
**         *Fixed bug where bessi(0,0) returned 0 instead of 1.
**         *Fixed source so that it compiles without warnings under 
**          gcc -O2 -Wall
**         *Cleaned up the files from when I used to distribute Eval on Simtel
**          and Garbo.  Deleted redundant files from the distribution.
**         *Updated address information.
**
** v1.13   4-13-93
**         *I changed the command line argument interpretation so that eval
**          could evaluate a single expression and quit.
**
** v1.12   4-9-93
**         *I added a default write directory and read path for scripts, 
**          and I added the ability to specify a certain page of help.
**
** v1.11   approx 2/93
**         *A version I never released.  I added better script support.
**
** v1.10   approx 1/93
**         *A friend of mine asked me to put Eval in the public domain,
**          so I figured I'd better dress it up a little.  I added more
**          flexible output (user specified precision), automatic pausing
**          every 22 lines, and the ability to specify input and output
**          in any number base.
**
** v1.00   9/88
**         *Eval was originally written to be a flexible PC calculator.
**          Since I work in a lab where bessel functions are frequently used,
**          I placed emphasis on putting bessel functions in the code.  I
**          also wanted something more powerful than a simple mock-up of an
**          actual calculator.  And since I own an Amiga but work with
**          IBM PC clones, I used ANSI C for portability.  This version
**          stayed fairly constant over four years, and I ran it on unix,
**          VMS, and PC (Amiga, IBM, Mac) platforms.
**
** Eval is a floating point expression evaluator.
** Copyright (C) 1993-2006 http://willus.com
**
** 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 2 of the License, or 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, write to the Free Software Foundation, Inc.,
** 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Originally written 5/89 in ANSI C
**
*/