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/* {{{ License.
 * 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
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */ //}}}

// :indentSize=4:lineSeparator=\n:noTabs=false:tabSize=4:folding=explicit:collapseFolds=0:
package org.mathpiper.builtin.functions.core;

import org.mathpiper.builtin.BigNumber;
import org.mathpiper.builtin.BuiltinFunction;
import org.mathpiper.lisp.Utility;

import org.mathpiper.lisp.Environment;

import org.mathpiper.lisp.Utility;

 *Corresponds to the MathPiper function AddN.
 *If called with one argument (unary plus), this argument is
 *converted to BigNumber. If called with two arguments (binary plus),
 *both argument are converted to a BigNumber, and these are added
 *together at the current getPrecision. The sum is returned.
 * See: getNumber(), BigNumber::Add().
00038 public class Add extends BuiltinFunction

    public void evaluate(Environment aEnvironment, int aStackTop) throws Exception
        int length = Utility.listLength(getArgumentPointer(aEnvironment, aStackTop, 0));
        if (length == 2)
            BigNumber x;
            x = Utility.getNumber(aEnvironment, aStackTop, 1);
            getTopOfStackPointer(aEnvironment, aStackTop).setCons(new org.mathpiper.lisp.cons.NumberCons(aEnvironment, x));
        } else
            BigNumber x = Utility.getNumber(aEnvironment, aStackTop, 1);
            BigNumber y = Utility.getNumber(aEnvironment, aStackTop, 2);
            int bin = aEnvironment.getPrecision();
            BigNumber z = new BigNumber(bin);
            z.add(x, y, aEnvironment.getPrecision());
            getTopOfStackPointer(aEnvironment, aStackTop).setCons(new org.mathpiper.lisp.cons.NumberCons(aEnvironment, z));
}//end class.

%mathpiper_docs,name="AddN",categories="User Functions;Numeric"
*CMD AddN --- add two numbers (arbitrary-precision math function)


This command performs the calculation of an elementary mathematical
function.  The arguments <i>must</i> be numbers.  The reason for the
postfix {N} is that the library needs to define equivalent non-numerical
functions for symbolic computations, such as {Exp}, {Sin}, etc.

Note that all xxxN functions accept integers as well as floating-point numbers.
The resulting values may be integers or floats.  If the mathematical result is an
exact integer, then the integer is returned.  For example, {Sqrt(25)} returns
the integer {5}, and {Power(2,3)} returns the integer {8}.  In such cases, the
integer result is returned even if the calculation requires more digits than set by
{BuiltinPrecisionSet}.  However, when the result is mathematically not an integer,
the functions return a floating-point result which is correct only to the current precision.



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