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package org.apache.poi.ss.formula.functions;

import org.apache.poi.ss.formula.eval.BlankEval;
import org.apache.poi.ss.formula.eval.ErrorEval;
import org.apache.poi.ss.formula.eval.MissingArgEval;
import org.apache.poi.ss.formula.eval.ValueEval;

Common interface for all implementations of Excel built-in functions.
Author:
Amol S. Deshmukh < amolweb at ya hoo dot com >/**
 * Common interface for all implementations of Excel built-in functions.
 *
 * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
 */
public interface Function {

	
Params:
args – the evaluated function arguments. Empty values are represented with BlankEval or MissingArgEval, never null.
srcRowIndex – row index of the cell containing the formula under evaluation
srcColumnIndex – column index of the cell containing the formula under evaluation
Returns:
The evaluated result, possibly an ErrorEval, never null.
Note - Excel uses the error code #NUM! instead of IEEE NaN, so when numeric functions evaluate to Double.NaN be sure to translate the result to ErrorEval.NUM_ERROR./**
	 * @param args the evaluated function arguments.  Empty values are represented with
	 * {@link BlankEval} or {@link MissingArgEval}, never <code>null</code>.
	 * @param srcRowIndex row index of the cell containing the formula under evaluation
	 * @param srcColumnIndex column index of the cell containing the formula under evaluation
	 * @return The evaluated result, possibly an {@link ErrorEval}, never <code>null</code>.
	 * <b>Note</b> - Excel uses the error code <i>#NUM!</i> instead of IEEE <i>NaN</i>, so when
	 * numeric functions evaluate to {@link Double#NaN} be sure to translate the result to {@link
	 * ErrorEval#NUM_ERROR}.
	 */
	ValueEval evaluate(ValueEval[] args, int srcRowIndex, int srcColumnIndex);
}