Type Geometry

[RudolfMan]

When using with TypedEctoSchema

defmodule MyApp.Service do
  use TypedEctoSchema

  typed_schema "services" do
    field :location, Geo.PostGIS.Geometry
    field :foo, :integer
  end
end

it tries to create a type for the schema as

  @type t() :: %__MODULE__{
          location: Geo.PostGIS.Geometry.t()
          foo: integer()
          ...
        }

And Geometry.t() is not declared.

Current workaround for us is declaring that type in our application

defmodule MyApp.Geo.PostGIS.Geometry do
  @type t ::
            Geo.Point.t()
            | Geo.PointZ.t()
            ...
end

and refer to it in schema

typed_schema "services" do
  field(:location, Geo.PostGIS.Geometry) :: MyApp.Geo.PostGIS.Geometry.t()
  field :foo, :integer
end

[RudolfMan]

We could use some macro to generate this..

something like

@type t :: unquote(Enum.reduce(@geometries, fn g, acc -> {:|, [], [g, acc]} end))

but I'm not sure if it's better..

[s3cur3]

Mmm, right... I do think we should build the type automatically from the @geometries list, just so that the long-term maintenance doesn't depend on remembering to add new types in both places. We could potentially wrap the AST generation in a macro like this, but I'd be comfortable with the above inline unquote with a comment explaining that it's producing the union of all the geometry types.

[RudolfMan]

hey! actually this is already declared as Geo.geometry() all we need is just to refer to it!

[s3cur3]

Ahhh! Thanks for this, @RudolfMan! I'm excited to finally be able to get rid of the Dialyzer ignore rule I've been carrying for years. 😆

[s3cur3]

Mmm, right... I do think we should build the type automatically from the @geometries list, just so that the long-term maintenance doesn't depend on remembering to add new types in both places. We could potentially wrap the AST generation in a macro like this, but I'd be comfortable with the above inline unquote with a comment explaining that it's producing the union of all the geometry types.

[axelson]

Nice find! Getting the typing right here will be soo nice.