Get execution to a point where we can run (<?q db find args).

src/datomish/clauses.cljc

@@ -32,7 +32,8 @@
 ;;   * Projection expressions, if only used for output.
 ;;   * Inline expressions?
 ;; `not` turns into NOT EXISTS with WHERE clauses inside the subquery to
-;; bind it to the outer variables.
+;; bind it to the outer variables, or adds simple WHERE clauses to the outer
+;; clause.
 ;; `not-join` is similar, but with explicit binding.
 ;; `or` turns into a collection of UNIONs inside a subquery.
 ;; `or`'s documentation states that all clauses must include the same vars,

src/datomish/db.cljc

@@ -8,25 +8,63 @@
       [datomish.pair-chan :refer [go-pair <?]]
       [cljs.core.async.macros :refer [go]]))
   (:require
-   [datomish.util :as util :refer [raise-str]]
+   [datomish.context :as context]
+   [datomish.projection :as projection]
+   [datomish.query :as query]
+   [datomish.source :as source]
    [datomish.sqlite :as s]
    [datomish.sqlite-schema :as sqlite-schema]
+   [datomish.util :as util :refer [raise-str]]
    #?@(:clj [[datomish.pair-chan :refer [go-pair <?]]
-             [clojure.core.async :as a :refer [go <! >!]]])
+             [clojure.core.async :as a :refer [chan go <! >!]]])
    #?@(:cljs [[datomish.pair-chan]
-              [cljs.core.async :as a :refer [<! >!]]])))
+              [cljs.core.async :as a :refer [chan <! >!]]])))
 
 (defprotocol IDB
+  (query-context
+    [db])
   (close
     [db]
     "Close this database. Returns a pair channel of [nil error]."))
 
 (defrecord DB [sqlite-connection]
   IDB
-  (close [db] (close (.-sqlite-connection db))))
+  (query-context [db] (context/->Context (source/datoms-source db) nil nil))
+  (close [db] (s/close (.-sqlite-connection db))))
 
 (defn <with-sqlite-connection [sqlite-connection]
   (go-pair
     (when-not (= sqlite-schema/current-version (<? (sqlite-schema/<ensure-current-version sqlite-connection)))
       (raise-str "Could not ensure current SQLite schema version."))
     (->DB sqlite-connection)))
+
+(defn <?run
+  "Execute the provided query on the provided DB.
+   Returns a transduced channel of [result err] pairs.
+   Closes the channel when fully consumed."
+  [db find args]
+  (let [parsed (query/parse find)
+        context (-> db
+                  query-context
+                  (query/expand-find-into-context parsed))
+        row-pair-transducer (projection/row-pair-transducer context)
+        sql (query/context->sql-string context args)
+        chan (chan 50 row-pair-transducer)]
+
+    (s/<?all-rows (.-sqlite-connection db) sql chan)
+    chan))
+
+(defn reduce-error-pair [f [rv re] [v e]]
+  (if re
+    [nil re]
+    (if e
+      [nil e]
+      [(f rv v) nil])))
+
+(defn <?q
+  "Execute the provided query on the provided DB.
+   Returns a transduced pair-chan with one [[results] err] item."
+  [db find args]
+  (a/reduce (partial reduce-error-pair conj) [[] nil]
+            (<?run db find args)))
+    

src/datomish/exec.cljc

@@ -1,40 +0,0 @@
-;; This Source Code Form is subject to the terms of the Mozilla Public
-;; License, v. 2.0. If a copy of the MPL was not distributed with this
-;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-(ns datomish.exec
-  #?(:cljs
-     (:require-macros
-      [datomish.util :refer [while-let]]
-      [datomish.pair-chan :refer [go-pair <?]]
-      [cljs.core.async.macros :refer [go]]))
-  (:require
-   [datomish.sqlite :as s]
-   [datomish.sqlite-schema :as ss]
-   [datomish.query :as dq]
-   #?@(:clj
-       [[datomish.jdbc-sqlite]
-        [datomish.pair-chan :refer [go-pair <?]]
-        [datomish.util :refer [while-let]]
-        [clojure.core.async :refer
-         [go                   ; macro in cljs.
-          <! >! chan close! take!]]])
-   #?@(:cljs
-       [[datomish.promise-sqlite]
-        [datomish.pair-chan]
-        [datomish.util]
-        [cljs.core.async :as a :refer
-         [<! >! chan close! take!]]])))
-
-(defn <?run
-  "Execute the provided query on the provided DB.
-   Returns a transduced channel of [result err] pairs.
-   Closes the channel when fully consumed."
-  [db find]
-  (let [initial-context (dq/make-context)
-        context (dq/expand-find-into-context initial-context (dq/parse find))
-        row-pair-transducer (dq/row-pair-transducer context (dq/sql-projection context))
-        chan (chan 50 row-pair-transducer)]
-
-    (s/<?all-rows db (dq/context->sql-string context) chan)
-    chan))

src/datomish/exec_repl.cljc

@@ -9,6 +9,7 @@
       [datomish.pair-chan :refer [go-pair <?]]
       [cljs.core.async.macros :refer [go]]))
   (:require
+     [datomish.db :as db]
      [datomish.exec :as exec]
      [datomish.sqlite :as s]
      [datomish.sqlite-schema :as ss]
@@ -41,7 +42,7 @@
   [db find]
   (pair-channel->lazy-seq (exec/<?run db find))))
 
-#_(defn xxopen []
+(defn xxopen []
     (datomish.pair-chan/go-pair
       (let [d (datomish.pair-chan/<? (s/<sqlite-connection "/tmp/foo.sqlite"))]
         (clojure.core.async/<!! (ss/<ensure-current-version d))
@@ -58,13 +59,10 @@
       "/tmp/foo.sqlite"
       '[:find ?page :in $ :where [?page :page/starred true ?t]]))
 
-#_(defn test-run []
-    (datomish.pair-chan/go-pair
-      (let [d (datomish.pair-chan/<? (s/<sqlite-connection "/tmp/foo.sqlite"))]
-        (<! (ss/<ensure-current-version d))
-        (let [chan (exec/<?run d
-                               '[:find ?page :in $ :where [?page :page/starred true ?t]])]
-          (println (datomish.pair-chan/<? chan))
-          (println (datomish.pair-chan/<? chan))
-          (println (datomish.pair-chan/<? chan))
-          (s/close d)))))
+#_
+(go-pair
+  (let [connection (<? (s/<sqlite-connection "/tmp/foo.sqlite"))
+        d (<? (db/<with-sqlite-connection connection))]
+    (println
+      "Result: "
+      (<! (db/<?q d '[:find ?page :in $ :where [?page :page/starred true ?t]] {})))))

src/datomish/projection.cljc

@@ -12,7 +12,6 @@
   )
 
 (defn lookup-variable [cc variable]
-  (println "Looking up " variable " in " (:bindings cc))
   (or (-> cc :bindings variable first)
       (raise-str "Couldn't find variable " variable)))
 
@@ -36,6 +35,7 @@
    @param context A Context, containing elements.
    @return a sequence of pairs."
   [context]
+  (def foo context)
   (let [elements (:elements context)]
     (when-not (every? #(instance? Variable %1) elements)
       (raise-str "Unable to :find non-variables."))
@@ -44,10 +44,10 @@
              [(lookup-variable (:cc context) var) (util/var->sql-var var)]))
          elements)))
 
-(defn row-pair-transducer [context projection]
+(defn row-pair-transducer [context]
   ;; For now, we only support straight var lists, so
   ;; our transducer is trivial.
-  (let [columns-in-order (map second projection)]
+  (let [columns-in-order (map second (sql-projection context))]
     (map (fn [[row err]]
            (if err
              [row err]

src/datomish/query.cljc

@@ -60,6 +60,8 @@
     (raise-str "`with` not supported.")))
 
 (defn- validate-in [in]
+  (when (nil? in)
+    (raise-str ":in expression cannot be nil."))
   (when-not (= "$" (name (-> in first :variable :symbol)))
     (raise-str "Non-default sources not supported."))
   (when-not (every? (partial instance? BindScalar) (rest in))
@@ -81,7 +83,11 @@
     {}
     in))
 
-(defn expand-find-into-context [context find]
+(defn find-into-context
+  "Take a parsed `find` expression and return a fully populated
+  Context. You'll want this so you can get access to the
+  projection, amongst other things."
+  [context find]
   (let [{:keys [find in with where]} find]  ; Destructure the Datalog query.
     (validate-with with)
     (validate-in in)
@@ -90,15 +96,18 @@
              :elements (:elements find)
              :cc (clauses/patterns->cc (:default-source context) where external-bindings)))))
 
+(defn context->sql-string
+  [context args]
+  (-> context
+    context->sql-clause
+    (sql/format args :quoting sql-quoting-style)))
+
 (defn find->sql-clause
   "Take a parsed `find` expression and turn it into a structured SQL
    expression that can be formatted by honeysql."
   [context find]
-  ;; There's some confusing use of 'where' and friends here. That's because
-  ;; the parsed Datalog includes :where, and it's also input to honeysql's
-  ;; SQL formatter.
   (->> find
-       (expand-find-into-context context)
+       (find-into-context context)
        context->sql-clause))
 
 (defn find->sql-string

src/datomish/sqlite.cljc

@@ -59,7 +59,9 @@
    when no more results exist. Consume with <?."
   [db [sql & bindings :as rest] chan]
   (go-safely [c chan]
-    (let [result (<! (-each db sql bindings (fn [row] (put! c [row nil]))))]
+    (let [result (<! (-each db sql bindings
+                            (fn [row]
+                              (put! c [row nil]))))]
       ;; We assume that a failure will result in the promise
       ;; channel being rejected and no further row callbacks
       ;; being called.