Qualified names

[madstap]

When using hodur I ran into an issue with names.

(def meta-db
  (engine/init-schema
   '[^{:spec/tag-recursive true
       :datomic/tag-recursive true}
     tx
     [^Integer amount]]))

(hodur-spec/defspecs meta-db {:prefix :foo}) ;=> [:foo.tx/amount :foo/tx]

(hodur-datomic/schema meta-db) ;=>
[#:db{:ident :tx/amount,
      :valueType :db.type/long,
      :cardinality :db.cardinality/one}]

The amount attribute is defined as :foo.tx/amount when it's a
spec, and just :tx/amount in the db. I want to have the same
identifier for the same attribute everywhere in my clojure code, so
amount would be called :foo.tx/amount everywhere. I also ran into this
same issue when writing a plugin to generate a json (de)serializer.

(def meta-db
  (engine/init-schema
   '[^{:spec/tag-recursive true
       :datomic/tag-recursive true
       :json-serde/tag-recursive true}
     tx
     [^Integer amount]]))

(hodur-spec/defspecs meta-db {:prefix :foo}) ;=> [:foo.tx/amount :foo/tx]

;; When I write my own plugin it needs the prefix arg
(def parse-json
  (hodur-json/parser meta-db :tx {:prefix :foo}))

;; To use the same qualified name everywhere, I wrote a wrapper
(def schema
  (my-hodur-datomic-wrapper/schema meta-db {:prefix :foo}))

Now I need to pass the prefix a bunch of places in the code. It would
be better to specify the prefix together with the rest of the data
model.

I think most plugins are going to want to refer to a canonical, unique,
qualified name for each attribute, so I feel like this
should be the responsibility of hugin-engine.

The api I want is the following:

(def meta-db
  (engine/init-schema
   '[^{:spec/tag-recursive true
       :datomic/tag-recursive true
       :json-serde/tag-recursive true
       :ns-prefix/tag-recursive :foo}
     tx
     [^Integer amount]]))

(hodur-spec/defspecs meta-db) ;=> [:foo.tx/amount :foo/tx]

(def parse-json
  (hodur-json/parser meta-db :foo/tx))

(parse-json "{\"amount\":10}") ;=> {:foo.tx/amount 10}

(def schema
  (hodur-datomic/schema meta-db))
;; =>
[#:db{:ident :foo.tx/amount,
      :valueType :db.type/long,
      :cardinality :db.cardinality/one}]

When no ns-prefix is specified, default to the current namespace, like the spec plugin.

(ns my.app
  (:require [hodur-engine.core :as engine]))

(def meta-db
  (engine/init-schema
   '[^{:spec/tag-recursive true}
     tx
     [^Integer amount]]))

(hodur-spec/defspecs meta-db) ;=> [:my.app.tx/amount :my.app/tx]

On the meta-api side, this would involve adding a
:<node-type>/qualified-name to each entity.

{:type/qualified-name  :foo/tx}
{:field/qualified-name :foo.tx/amount}
{:param/qualified-name :foo.tx.nested/param}

The downside to all this is that it would be a breaking change
for the datomic plugin and maybe others.

What do you think? How would you structure the namespaces?

[madstap]

Actually doesn't need to be a breaking change to anything if you don't default to the current namespace.

{:ns-prefix/tag true} can mean the current namespace.