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