From fbd5863921f1c66fb0ef84cbd8466ae6b3c92ddc Mon Sep 17 00:00:00 2001
From: Nick Alexander <nalexander@mozilla.com>
Date: Wed, 27 Jul 2016 14:29:51 -0700
Subject: [PATCH] Resolve lookup-refs.

---
 src/datomish/db.cljc | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/datomish/db.cljc b/src/datomish/db.cljc
index f2a61ca4..e1103f15 100644
--- a/src/datomish/db.cljc
+++ b/src/datomish/db.cljc
@@ -315,6 +315,10 @@
         (transduce conj [] initial-es))
       (assoc-in report [:entities]))))
 
+(defn- lookup-ref? [x]
+  (and (sequential? x)
+       (= (count x) 2)))
+
 (defn <?run
   "Execute the provided query on the provided DB.
    Returns a transduced channel of [result err] pairs.
@@ -345,6 +349,17 @@
   (a/reduce (partial reduce-error-pair conj) [[] nil]
             (<?run db find args)))
 
+
+(defn <resolve-lookup-refs [db report]
+  (go-pair
+    (->>
+      (vec (for [[op & entity] (:entities report)]
+             (into [op] (for [field entity]
+                          (if (lookup-ref? field)
+                            (first (<? (<eavt db field))) ;; TODO improve this
+                            field)))))
+      (assoc-in report [:entities])))) ;; TODO: meta.
+
 (defonce -eid (atom (- 0x200 1)))
 
 ;; TODO: better here.
@@ -497,6 +512,9 @@
     (->> initial-report
          (preprocess db)
 
+         (<resolve-lookup-refs db)
+         (<?)
+
          (<resolve-id-literals db)
          (<?)