[%########################################
  form_checkbox( name, value, picked )
    Generate a checkbox that's checked if value == picked.
  ########################################-%]

[%- is_checked = ( value == picked ) ? 'CHECKED' : '' -%] 
<input type="checkbox" name="[% name %]"
       value="[% value %]" [% is_checked %]> [% field_label %]