Provide separate prefix and suffix values for the start and end values

Do you have any plans for this? :)
thepearson solved it in the ex-Ranges module (mentioned in #1912804: Merge with thepearson's Ranges sandbox module?) with providing separate prefix and suffix instance settings for the separate start and end values.

Here are some relevant code snippets taken from the file ranges.module, see the ['start']['prefix'], ['start']['suffix'], ['end']['prefix'] and ['end']['suffix'] array indices:

line 55-95:

/**
 * Implements hook_field_info().
 */
function ranges_field_info() {
  return array(
    'ranges' => array(
      'label' => t('Range'),
      'description' => t('Provides ability to specify numerical ranges.'),
      'instance_settings' => array(
        'start' => array(
          'min_value' => '',
          'max_value' => '',
          'prefix' => '',
          'suffix' => '',
          'size' => 12,
          'title' => t('Start'),
        ),
        'end' => array(
          'min_value' => '',
          'max_value' => '',
          'prefix' => '',
          'suffix' => '',
          'size' => 12,
          'title' => t('End'),
        ),
        'formatting' => array(
          'prefix' => '',
          'suffix' => '',
          'indicator' => '-',
        ),
      ),
      'settings' => array(
        'type' => 'integer',
      ),
      'default_widget' => 'ranges_textfield',
      'default_formatter' => 'default',
      'property_type' => 'field_ranges_field',
      'property_callbacks' => array('ranges_field_property_info_callback'),
    ),
  );
}

line 200-353 :

/**
 * Implements hookd_field_instance_settings_form().
 */
function ranges_field_instance_settings_form($field, $instance) {
  $settings = $instance['settings'];

  $form['start'] = array(
    '#type' => 'fieldset',
    '#collapsible' => TRUE,
    '#title' => t('Start value limits'),
  );

  $form['start']['min_value'] = array(
    '#type' => 'textfield',
    '#title' => t('Min'),
    '#size' => 12,
    '#description' => t('Specify a minimum value for the start value. Leave blank for none.'),
    '#default_value' => isset($settings['start']['min_value']) ? $settings['start']['min_value'] : '',
  );

  $form['start']['max_value'] = array(
    '#type' => 'textfield',
    '#title' => t('Max'),
    '#size' => 12,
    '#description' => t('Specify a maximum value for the start value. Leave blank for none.'),
    '#default_value' => isset($settings['start']['max_value']) ? $settings['start']['max_value'] : '',
  );

  $form['start']['prefix'] = array(
    '#type' => 'textfield',
    '#title' => t('Start prefix'),
    '#size' => 12,
    '#description' => t('Specify a value to place in front of the start field. (eg $)'),
    '#default_value' => isset($settings['start']['prefix']) ? $settings['start']['prefix'] : '',
  );

  $form['start']['suffix'] = array(
    '#type' => 'textfield',
    '#title' => t('Start suffix'),
    '#size' => 12,
    '#description' => t('Specify a value to place after the start field. (eg .00)'),
    '#default_value' => isset($settings['start']['suffix']) ? $settings['start']['suffix'] : '',
  );

  $form['start']['size'] = array(
    '#type' => 'textfield',
    '#title' => t('Size'),
    '#size' => 12,
    '#description' => t('Specify a size for the field.'),
    '#default_value' => isset($settings['start']['size']) ? $settings['start']['size'] : 6
  );

  $form['start']['title'] = array(
    '#type' => 'textfield',
    '#title' => t('Title'),
    '#size' => 20,
    '#description' => t('Specify a maximum value for the start value. Leave blank for none.'),
    '#default_value' => isset($settings['start']['title']) ? $settings['start']['title'] : t('Start'),
  );

  $form['end'] = array(
    '#type' => 'fieldset',
    '#collapsible' => TRUE,
    '#title' => t('End value limits'),
  );

  $form['end']['min_value'] = array(
    '#type' => 'textfield',
    '#title' => t('Min'),
    '#size' => 12,
    '#description' => t('Specify a minimum value for the end value. Leave blank for none.'),
    '#default_value' => isset($settings['end']['min_value']) ? $settings['end']['min_value'] : '',
  );

  $form['end']['max_value'] = array(
    '#type' => 'textfield',
    '#title' => t('Max'),
    '#size' => 12,
    '#description' => t('Specify a maximum value for the end value. Leave blank for none.'),
    '#default_value' => isset($settings['end']['max_value']) ? $settings['end']['max_value'] : '',
  );

  $form['end']['prefix'] = array(
    '#type' => 'textfield',
    '#title' => t('End prefix'),
    '#size' => 12,
    '#description' => t('Specify a value to place in front of the end field. (eg $)'),
    '#default_value' => isset($settings['end']['prefix']) ? $settings['end']['prefix'] : '',
  );

  $form['end']['suffix'] = array(
    '#type' => 'textfield',
    '#title' => t('End suffix'),
    '#size' => 12,
    '#description' => t('Specify a value to place after the end field. (eg .00)'),
    '#default_value' => isset($settings['end']['suffix']) ? $settings['end']['suffix'] : '',
  );

  $form['end']['size'] = array(
    '#type' => 'textfield',
    '#title' => t('Size'),
    '#size' => 12,
    '#description' => t('Specify a size for the field.'),
    '#default_value' => isset($settings['end']['size']) ? $settings['end']['size'] : 6,
  );

  $form['end']['title'] = array(
    '#type' => 'textfield',
    '#title' => t('Title'),
    '#size' => 20,
    '#description' => t('Specify a maximum value for the end value. Leave blank for none.'),
    '#default_value' => isset($settings['end']['title']) ? $settings['end']['title'] : t('End'),
  );

  $form['formatting'] = array(
    '#type' => 'fieldset',
    '#title' => t('More'),
    '#description' => t('These formatting options affect the range as a whole.'),
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
  );
  $form['formatting']['prefix'] = array(
    '#type' => 'textfield',
    '#title' => t('Prefix'),
    '#size' => 12,
    '#description' => t('Specify a value to place in front of the range field.'),
    '#default_value' => isset($settings['formatting']['prefix']) ? $settings['formatting']['prefix'] : '',
  );

  $form['formatting']['suffix'] = array(
    '#type' => 'textfield',
    '#title' => t('Suffix'),
    '#size' => 12,
    '#description' => t('Specify a value to place after the entire range field.'),
    '#default_value' => isset($settings['formatting']['suffix']) ? $settings['formatting']['suffix'] : '',
  );

  $form['formatting']['indicator'] = array(
    '#type' => 'textfield',
    '#title' => t('Sperator'),
    '#size' => 12,
    '#description' => t('Specify an indicator to display between the two range values.'),
    '#default_value' => isset($settings['formatting']['indicator']) ? $settings['formatting']['indicator'] : '-',
  );

  $form['formatting']['force_end_greater'] = array(
    '#type' => 'checkbox',
    '#title' => t('Force end to be greater'),
    '#description' => t('Check this box to force the "end" range value to be greater than the "start" value.'),
    '#default_value' => isset($settings['formatting']['force_end_greater']) ? $settings['formatting']['force_end_greater'] : 0,
  );

  return $form;
}

line 356-389:

/**
 * Implements hook_field_widget_form().
 */
function ranges_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {

  if ($instance['widget']['type'] == 'ranges_textfield') {

    $element['range'] = array(
      '#type' => 'fieldset',
      '#title' => check_plain($instance['label']),
    );

    $element['range']['range_start'] = array(
      '#type' => 'textfield',
      '#prefix' => isset($instance['settings']['formatting']['prefix']) ? $instance['settings']['formatting']['prefix'] : NULL,
      '#title' => isset($instance['settings']['start']['title']) ? $instance['settings']['start']['title'] : t('Start'),
      '#field_prefix' => isset($instance['settings']['start']['prefix']) ? $instance['settings']['start']['prefix'] : NULL,
      '#field_suffix' => isset($instance['settings']['start']['suffix']) ? $instance['settings']['start']['suffix'] : NULL,
      '#size' => isset($instance['settings']['start']['size']) ? $instance['settings']['start']['size'] : 6,
      '#default_value' => isset($items[$delta]['range_start']) ? $items[$delta]['range_start'] : '',
    );

    $element['range']['range_end'] = array(
      '#type' => 'textfield',
      '#suffix' => isset($instance['settings']['formatting']['suffix']) ? $instance['settings']['formatting']['suffix'] : NULL,
      '#title' => isset($instance['settings']['end']['title']) ? $instance['settings']['end']['title'] : t('End'),
      '#field_prefix' => isset($instance['settings']['end']['prefix']) ? $instance['settings']['end']['prefix'] : NULL,
      '#field_suffix' => isset($instance['settings']['end']['suffix']) ? $instance['settings']['end']['suffix'] : NULL,
      '#size' => isset($instance['settings']['end']['size']) ? $instance['settings']['end']['size'] : 6,
      '#default_value' => isset($items[$delta]['range_end']) ? $items[$delta]['range_end'] : '',
    );
  }
  return $element;
}

line 518-536:

/**
 * Implements hook_field_formatter_view().
 */
function ranges_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  foreach ($items as $delta => $item) {
    $element[$delta] = array('#markup' => implode('', array(
      $instance['settings']['formatting']['prefix'] . ' ',
      $instance['settings']['start']['prefix'],
      $item['range_start'],
      $instance['settings']['start']['suffix'] . ' ',
      $instance['settings']['formatting']['indicator'] . ' ',
      $instance['settings']['end']['prefix'],
      $item['range_end'],
      $instance['settings']['end']['suffix'] . ' ',
      $instance['settings']['formatting']['suffix'],
    )));
  }
  return $element;
}

etc.

Thanks in advance!

Wow, thank you very much, Taran2L! :) I've just tested it, and it works.

And I'm really sorry that I reopen this issue, but couldn't we ALSO keep the old prefixes and suffixes, like the ex-Ranges module did? (Sorry that I didn't mention it in the original feature request. :( )
I know it may sound silly, but there may be some weird cases it's needed, and it would be much better to keep another additional opportunity to make this module even better.
So what I'm thinking about is the following (see WRAPPERPREFIX and WRAPPERSUFFIX):

WRAPPERPREFIX testprefix 1234 testsuffix — another testprefix 234132 another testsuffix WRAPPERSUFFIX

This is how it looks like now:

What I think would be even better:

And this is what the field edit form would look like:

I hope you won't find this a silly idea, and there's a chance to implement it too (e.g. with putting back some parts of the old code).
I'll try to help with a patch as soon as I'll have time if needed.

Thank you very much in advance again!