Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.numeric;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class ATanFunction extends AbstractFunction {

    public ATanFunction() {

        super("Numeric", "ATAN", Range.is(1),

            "Returns the arc tangent of a value; the returned angle is in the range -pi/2 through pi/2. Special cases:\n" +

            "- If the argument is NaN, then the result is NaN.\n" +

            "- If the argument is zero, then the result is a zero with the same sign as the argument.\n" +

            "The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.\n",

            "ATAN({{a}})",

            new String[]{

                "a - the value whose arc tangent is to be returned."

            },

            "Double"

        );

    }

    @Override

    public Object call(Interpreter interpreter, Object[] args) {

        double r = Math.atan(getDouble(args, 0));

        return r;

    }

}