protected static Ptg calcLeft( Ptg[] operands )
	{
		int numchars = 1;
		if( operands.length < 1 )
		{
			return new PtgErr( PtgErr.ERROR_VALUE );
		}
		if( operands[0] instanceof PtgErr )
		{
			return new PtgErr( PtgErr.ERROR_NA );    // 'tis what excel does
		}
		if( operands.length == 2 )
		{
			if( operands[1] instanceof PtgErr )
			{
				return new PtgErr( PtgErr.ERROR_VALUE );
			}
			numchars = operands[1].getIntVal();
		}
		Object o = operands[0].getValue();
		if( o == null )
		{
			return new PtgStr( "" );
		}
		String str = String.valueOf( o );
		if( (str == null) || (numchars > str.length()) )
		{
			return new PtgStr( "" );    // 20081202 KSC: Don't error out if not enough chars ala Excel
		}
		String res = str.substring( 0, numchars );
		return new PtgStr( res );
	}