Encapsulating Specifications
You can give a specification a name and attach it to a fact type.
Use the Relation type to define a property.
[FactType("Construction.Project")]
public record Project(User creator, Guid id)
{
public Relation<ProjectName> Names => Relation.Define(_ =>
this.Successors().OfType<ProjectName>(n => n.project)
.WhereCurrent((ProjectName next) => next.prior)
);
}
var namesOfProject = Given<Project>.Match(p =>
p.Names
);Since the Jinaga.User type is defined in the Jinaga library, you need to use an extension member to add a relation to it.
public static class UserExtensions
{
extension(User user)
{
public Relation<Project> Projects => Relation.Define(_ =>
user.Successors().OfType<Project>(p => p.creator)
.WhereNotDeletedOrRestored((ProjectDeleted d) => d.project,
(ProjectRestored r) => r.deleted));
}
}
var projectsCreatedByUser = Given<User>.Match(u =>
u.Projects
);