41.6 Resolving Intent Parameters
Each intent domain type has associated with it a group of parameters that are used to provide details about the task to be performed by the app. While many parameters are mandatory, some are optional. The intent to send a message must, for example, contain a valid recipient parameter in order for a message to be sent. A number of parameters for a Photo search intent, on the other hand, are optional. A user might, for example, want to search for photos containing particular people, regardless of the date that the photos were taken.
When working with Siri domains, Siri knows all of the possible parameters for each intent type, and for each parameter Siri will ask the app extension’s intent handler to resolve the parameter via a corresponding method call. If Siri already has a parameter, it will ask the intent handler to verify that the parameter is valid. If Siri does not yet have a value for a parameter it will ask the intent handler if the...
