{{alias}}( idx )
    Returns a function which always returns a specified argument.

    The input argument corresponds to the zero-based index of the argument to
    return.

    Parameters
    ----------
    idx: integer
        Argument index to return (zero-based).

    Returns
    -------
    out: Function
        Argument function.

    Examples
    --------
    > var argn = {{alias}}( 1 );
    > var v = argn( 3.14, -3.14, 0.0 )
    -3.14
    > v = argn( -1.0, -0.0, 1.0 )
    -0.0
    > v = argn( 'beep', 'boop', 'bop' )
    'boop'
    > v = argn( 'beep' )
    undefined

    See Also
    --------