{#
    Builds a single checkbox input.

    name        - The name of the form parameter.
    id          - The id to use on the input and label. Convention is to prefix with 'field-'.
    label       - The human readable label.
    value       - The value of the input.
    checked     - If true the checkbox will be checked
    error       - An error string for the field or just true to highlight the field.
    classes     - An array of classes to apply to the form-group.
    is_required - Boolean of whether this input is required for the form to validate

    Example:

    {% import 'macros/form.html' as form %}
    {{ form.checkbox('remember', checked=true) }}

    #}
{% macro checkbox(name, id='', label='', value='', checked=false, placeholder='', error="", classes=[], attrs={}, is_required=false) %}
    {%- set extra_html = caller() if caller -%}
    {{ ui.checkbox(extra_html, name=name, id=id, label=label, value=value, checked=checked, errors=error, attrs=attrs, required=is_required) }}
{% endmacro %}