References in YAML Configuration
You can use a static method call, a service method call, and class constant access in the YAML datagrid configuration. These references will be called by SystemAwareResolver while building the datagrid in the datagrid manager.
Call method getChoicesQuery with datagrid name and YAML configuration key as arguments from oro_email.grid.query_builder service.
Static Method Call
The class name can be defined in the container’s parameters or specified directly.
PHP is_callable is used to determine if it is callable or should be treated as constant.
The value becomes unchanged if it is not callable and no constant exists with such a name in the class.