many to many relationship

[FCO]

One of the best ways of doing a many-to-many relationship is something like this:

model Bli {...}

model Bla {
   has $!id   is serial;
   has $.a    is column;
   has @.bles is relationship( *.bla-id, :model<Ble>);
   method blis { self.bles.join-model(Bli, *.bli-id == *.id) }
}

model Ble {
   has $.bla-id is column{ :id, :references{ .id }, :model-name<Bla> };
   has $.bli-id is column{ :id, :references{ .id }, :model-name<Bli> };
}

model Bli {
   has $!id is serial;
   has $.i  is column;
   has @.bles is relationship( *.ble-id, :model<Ble>);
   method blas { self.bles.join-model(Bla, *.bla-id == *.id) }
}

red-defaults "SQLite";

schema(Bla, Ble, Bli).create;

Bla.^create: :a<bla1>;
Bli.^create: :i<bli1>;

Ble.^create: :1bla-id, :1bli-id;

.say for Bla.^load(1).blis 

But that has some problems, for example, it's not so easy to create new objects, so I think it should be improved.
Maybe something like this:

model Bla {
   has $!id   is serial;
   has $.a    is column;
   has @.bles is relationship( *.bla-id, :model<Ble>);
   has @.blis is relationship( *.bli-id, :many-to-many{ .bles }, :model<Bli> );
}

model Ble {
   has $.bla-id is column{ :id, :references{ .id }, :model-name<Bla> };
   has $.bli-id is column{ :id, :references{ .id }, :model-name<Bli> };
   has $.bla is relationship(*.bla-id, :model<Bla>);
   has $.bli is relationship(*.bli-id, :model<Bli>);
}

model Bli {
   has $!id is serial;
   has $.i  is column;
   has @.bles is relationship( *.ble-id, :model<Ble>);
   has @.blas is relationship( *.bla-id, :many-to-many{ .bles }, :model<Bla> );
}

But I'm not sure about that syntax. The important part is the @ sigil and some way of specifying 2 model/key pairs.

Something that should be defined is that we should use an intermediate to-many relationship:

has @.blis is relationship( *.bli-id, :many-to-many{ .bles }, :model<Bli> );

Or if we should specify 2 relationships:

has @.blis is relationship( :many{ .bles }, :to-many{ .bli } );

Or 2 pairs of column/model:

has @.blis is relationship( *.bli-id, :model<Bli>, :intermediate{ .bla-id }, :intermediate-model<Ble> );

Any suggestions?

[FCO]

maybe all should be accepted (with a more consistent syntax)

[FCO]

It's easily done with $post.post-tags>>.tag, so no need for special syntax.