def field_xpath(field, attribute):
    """
    Field helper functions to locate select, textarea, and the other
    types of input fields (text, checkbox, radio)

    :param field: One of the values 'select', 'textarea', 'option', or
    'button-element' to match a corresponding HTML element (and to
    match a <button> in the case of 'button-element'). Otherwise a
    type to match an <input> element with a type=<field> attribute.

    :param attribute: An attribute to be matched against, or 'value'
    to match against the content within element being matched.
    """
    if field in ['select', 'textarea']:
        xpath = './/{field}[@{attr}=%s]'
    elif field == 'button-role':
        if attribute == 'value':
            xpath = './/*[@role="button"][contains(., %s)]'
        else:
            xpath = './/*[@role="button"][@{attr}=%s]'
    elif field == 'button-element':
        field = 'button'
        if attribute == 'value':
            xpath = './/{field}[contains(., %s)]'
        else:
            xpath = './/{field}[@{attr}=%s]'
    elif field == 'option':
        xpath = './/{field}[@{attr}=%s]'
    else:
        xpath = './/input[@{attr}=%s][@type="{field}"]'
    return xpath.format(field=field, attr=attribute)
