Anatomy of a Dacite app

Every portable example in this repo splits Values from Store. Domain code builds and updates Dacite values. Wiring opens a rooted store. The two meet at v/root.

Copy this shape. Do not start from a single namespace that both assocs fields and chooses a file path.

Public API only

(require '[dacite.value :as v]
         '[dacite.store :as s])

If a domain function needs dacite.value.collections, dacite.store.pack, or dacite.convert, that is a library hole. Promote a function on dacite.value (or wrap the store) in the same change. See The Dacite way.

1. Domain functions take and return values

Constructors take a context first — a store, a root, or another value. New nodes persist into that store:

(defn add-todo [todos title]
  (v/conj todos (v/map todos "title" title "done" false)))

Reads name a field, not the whole tree:

(v/native (v/get todo "title"))
(boolean (v/native (v/get todo "done")))

2. Bootstrap once

(require '[dacite.store :as s]
         '[dacite.value :as v])

(def rs (s/mem))
(def r (v/root rs))
(def doc (v/map r
                "title" (v/string r "Hello")
                "done" false))

(v/native (v/get doc "title"))
;; => "Hello"

(s/hash->hex (v/hash doc))

Every constructor takes the context. There is no implicit *store* form.

3. One rooted store, one v/root

(v/cas! r nil doc)          ; seed empty root (local and remote)
(v/swap! r add-todo "milk") ; CAS-retry
(v/deref r)                 ; current Dacite value, or nil

There is no unconditional reset! on the value API. Seed with cas! from nil; update with swap!.

On the JVM, @r and swap! on the root object still work.

4. Store section is a different concern

(s/mem)
(s/file "target/my-app")
(s/file "target/my-app" {:reset true})
(s/remote "http://127.0.0.1:8080")   ; JVM; write-back by default

The domain namespace should still compile if you swap file for HTTP.

On write-back HTTP, puts stay in local memory until commit. Flush packs literals and POST /nodes, then POST /root/cas. Domain code does not call pack.

5. The whole loop

(def rs (s/file path))     ; Store section
(def r (v/root rs))        ; Value section
(load-or-seed! r)
(v/swap! r domain-op …)

load-or-seed! is deref or, if empty, cas! from nil.

That is the architecture in todo.cljc and the other portable examples.

Next

• First values — constructors and hashes, no root.
• Persist and update a document — nested map, file or HTTP.
• Values API / Stores API.