Trait django_query::filtering::MetaVisitor

source · [−]
pub trait MetaVisitor<R> {
    fn visit_member<F, O, T>(&mut self, name: &str, member: &F, defop: O)
    where
        F: Member<R, Value = T> + Clone + 'static,
        O: OperatorClass<<T as Operable>::Base> + 'static,
        <O as OperatorClass<<T as Operable>::Base>>::Instance: 'static,
        T: Operable;
    fn visit_record<F, T, U>(&mut self, name: &str, field: &F, inner_record: &T)
    where
        F: Field<R, Value = U> + Clone + 'static,
        T: Meta<U> + 'static,
        U: 'static;
}
Expand description

Something that can receive callbacks about the members and fields in a Meta.

A MetaVisitor can be passed to Meta::accept_visitor to receive a callback for each of the exposed members of a type.

Required methods

This should be called by Meta for each exposed structure field which is Operable. Here:

  • name is the name of the field, as exposed.
  • member is the Member for that field.
  • defop is the default OperatorClass for that field, which should be applied when no operator is specified (i.e. in the "record__field" case as opposed to the "record__field__op" case)

This should be called by Meta for each exposed structure field which can be traversed, that is where the type of the field is itself a structured type, for example when modelling foreign keys. Here:

  • name is the name of the field, as exposed.
  • field is the Field for that field (note the difference: there are no exposed operators for a Field, and operators are applied to the record type, since there could be no one Operable::Base type.
  • inner_record is the Meta for the field.

Implementors