Module Cf_data_render.Field

Use required k v f to compose a group field where a required output value with key k and value matching the model v obtained by applying the projector f to the rendered value.

Use optional k v f to compose a group field where an optional output value with key k and value matching the model v obtained by applying the projector f to the rendered value. If the projector returns None then no field with key k is output.

Use constant k v def to compose a group field where a required output value with key k and value def matching the model v is produced regardless of the rendered value.