diff --git a/src/Tpl.php b/src/Tpl.php
index 02ed8af..dc5e493 100644
--- a/src/Tpl.php
+++ b/src/Tpl.php
@@ -233,6 +233,106 @@ class Tpl {
     self :: $smarty -> registerPlugin("function", $name, $callable);
   }
 
+  /**
+   * Register a callable usable from template files
+   * @param callable $callable The callable
+   * @param string|null $name The name of the callable exposed in template files
+   *                          (optional, default: the function/method name)
+   * @param string|null $type The type of method:
+   *                          - "display" (default): the result of the callable execution will be
+   *                            displayed
+   *                          - "output_variable": the result of the callable execution will be
+   *                            assign to the template variable (name specified using
+   *                            $output_variable)
+   * @param string|null $output_variable The name of the output variable (optional, required if
+   *                                     $type == "output_variable")
+   * @return void
+   */
+  public static function register_callable($callable, $name=null, $type=null, $output_variable=null) {
+    if (!is_callable($callable))
+      self::fatal_error("Tpl::register_callable(): invalid callable provided");
+    if (is_array($callable)) {
+      if (is_object($callable[0]))
+        self::fatal_error(
+          "Tpl::register_callable(): can't register template function from instantiated object."
+        );
+      $class = new \ReflectionClass($callable[0]);
+      $method = $class->getMethod($callable[1]);
+      if (!$method->isStatic())
+        self::fatal_error(
+          "Tpl::register_callable(): can't register template function from non-static method."
+        );
+      $callable_txt = sprintf("['\\%s', '%s']", $callable[0], $callable[1]);
+      $params = $method->getParameters();
+      $default_smarty_function_name = sprintf(
+        "smarty_%s_%s",
+        str_replace("\\", "_", $class->getName()),
+        $method->getName()
+      );
+      $default_smarty_name = $method->getName();
+    }
+    else {
+      $function = new \ReflectionFunction($callable);
+      $default_smarty_function_name = "smarty_$function";
+      $default_smarty_name = $callable;
+      $callable_txt = $callable;
+      $params = $function->getParameters();
+    }
+    $args = [];
+    foreach($params as $idx => $param) {
+      if ($param->isOptional()) {
+        $args[] = sprintf(
+          "\$params['%s'] ?? %s",
+          $param->getName(),
+          var_export($param->getDefaultValue(), true)
+        );
+      }
+      else {
+        $args[] = sprintf("\$params['%s']", $param->getName());
+      }
+    }
+    $idx = 0;
+    $smarty_function_name = $default_smarty_function_name;
+    while (function_exists($smarty_function_name))
+      $smarty_function_name = $default_smarty_function_name . $idx++;
+    switch($type) {
+      case "output_variable":
+        if (!$output_variable)
+          self::fatal_error("Tpl::register_callable(): no output variable name specified");
+        $code = sprintf(
+          "function %s(\$params, \$smarty) {
+            \$smarty->assign(
+              '%s',
+              call_user_func_array(%s, [%s])
+            );
+          }",
+          $output_variable,
+          $smarty_function_name,
+          $callable_txt,
+          implode(", ", $args)
+        );
+        break;
+      case "display":
+      default:
+        $code = sprintf(
+          "function %s(\$params, \$smarty) {
+            echo call_user_func_array(%s, [%s]);
+          }",
+          $smarty_function_name,
+          $callable_txt,
+          implode(", ", $args)
+        );
+    }
+    $smarty_name = $name ?? $default_smarty_name;
+    Log::debug(
+      "Tpl::register_callable(): register template function %s from %s with following middleware ".
+      "function:\n%s",
+      $smarty_name, format_callable($callable), $code
+    );
+    eval($code);
+    self::register_function($smarty_name, $smarty_function_name);
+  }
+
   /**
    * Register a modifier usable from template files
    * @param string $name The modifier name