{{alias}}( str )
    Parses a regular expression string and returns a new regular expression.

    Provided strings should be properly escaped.

    If unable to parse a string as a regular expression, the function returns
    `null`.

    Parameters
    ----------
    str: string
        Regular expression string.

    Returns
    -------
    out: RegExp|null
        Regular expression or null.

    Examples
    --------
    > var re = {{alias}}( '/beep/' )
    /beep/
    > re = {{alias}}( '/beep' )
    null

    See Also
    --------