Flexible parameters, hard returns

When programming a function, or a method of a class, always is the best thing to be able to receive any type of parameter. Analyze if is more comfortable to mix two parameters in one, using an Array, or if a data can be of several types. All these things it is necessary to have them in account so that soon it is less difficult to work with which already it is done. Another thing that we must try is always to return the same data type, even if it were not possible to be made what it was expected, then if an Array is due to return, but was an error we can return an empty Array instead of false or null. A simple example of this



function select($nombre, $valores = array(), $seleccionado = '', $atributos = array())
{
if (!is_array($valores) || count($valores) == 0)
{
return '';
}

if (is_string($nombre))
{
if (is_array($atributos))
{
$atributos['name'] = $nombre;
} else
{
$atributos .= ' name="' . htmlentities($nombre) . '"';
}
}
$out = '<select';
if (is_array($atributos))
{
foreach ($atributos as $atributo_nombre => $atributo_valor)
{
$out .= ' ' . $atributo_nombre . '="' . htmlentities($atributo_valor) . '"';
}
} else
{
$out .= ' ' . $atributos;
}
$out .= '>';
foreach ((array)$valores as $valor_clave => $valor_etiqueta)
{
$out .= '<option value="' . htmlentities($valor_clave) . '"' . ($valor_clave == $seleccionado || (is_array($seleccionado) && in_array($valor_clave,$seleccionado)) ? 'selected="selected"' : '') . '>' . htmlentities($valor_etiqueta) . '</option>';
}
return $out . '</select>';
}

echo select('select',array('a' => 'A', 'b' => 'B','c' => 'C','d' => 'D'),array('a'),array('id' => 'select', 'multiple' => 'multiple'));
echo PHP_EOL;
echo select('select',array('a' => 'A', 'b' => 'B','c' => 'C','d' => 'D'),'a','id="select"');
echo PHP_EOL;
echo select('select');