The Yaf_Config_Simple construct method parameters may be wrong documenting, actually first parameter shoud be array and second is string indicating if readonly.(Yaf >=1.0.0)
Yaf_Config_Simple is a configuration adapter backed by a PHP array (or, optionally, an INI file). In contrast to Yaf_Config_Ini it is mutable by default: values can be changed at runtime, which makes it suitable both for programmatically built configuration and for configuration that needs to be adjusted during the request.
The Yaf_Config_Simple construct method parameters may be wrong documenting, actually first parameter shoud be array and second is string indicating if readonly.