first import

sites/all/modules/variable/variable_example/variable_example.module

@@ -0,0 +1,81 @@
+<?php
+/**
+ * Variable example.
+ */
+
+/**
+ * Implements hook_variable_realm_info()
+ */
+function variable_example_variable_realm_info() {
+  $realm['example'] = array(
+    'title' => t('Example'),
+    'weight' => 10,
+    'store class' => 'VariableStoreRealmStore',
+    'keys' => array(
+      'first' => t('First example'),
+      'second' => t('Second example'),
+    ),
+  );
+  return $realm;
+}
+
+/**
+ * Implements hook_menu().
+ */
+function variable_example_menu() {
+  $items['admin/config/system/variable_example'] = array(
+    'title' => 'Variable example',
+    'description' => 'Example of auto generated settings form.',
+    'page callback' => 'drupal_get_form',
+    'page arguments' => array('variable_group_form', 'variable_example'),
+    'access arguments' => array('administer site configuration'),
+  );
+  $items['variable/example'] = array(
+    'title' => 'Variable example',
+    'description' => 'List some variables.',
+    'page callback' => 'variable_example_page_list',
+    'access arguments' => array('administer site configuration'),
+  );
+  $items['variable/realm/%/%'] = array(
+    'title' => 'Variable example realm',
+    'description' => 'Example of variable realms.',
+    'page callback' => 'variable_example_page_realm',
+    'page arguments' => array(2, 3),
+    'access arguments' => array('administer site configuration'),
+  );
+  return $items;
+}
+
+/**
+ * Variable example realm page.
+ *
+ * Will switch to given realm and display variables.
+ */
+function variable_example_page_list() {
+  variable_include();
+  $list = variable_list_group('site_information') + variable_list_group('variable_example');
+  foreach ($list as $name => $variable) {
+    $build[$name] = array(
+      '#type' => 'item',
+      '#title' => $variable['title'],
+      '#markup' => variable_format_value($variable),
+    );
+  }
+  return $build;
+}
+
+/**
+ * Variable example realm page.
+ *
+ * Will switch to given realm and display variables.
+ */
+function variable_example_page_realm($realm, $key) {
+  // Initialize realm from variable store.
+  $variables = variable_store($realm, $key);
+  // Set at least one variable for the realm
+  $variables += array('site_name' => 'Variable example realm');
+  variable_realm_add($realm, $key, $variables);
+  variable_realm_switch($realm, $key);
+  return variable_example_page_list();
+}
+