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Added util/if+ which allows sharing vars between if condition and the…
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…n clause
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tonsky committed Jun 18, 2024
1 parent 9ae1fd5 commit 8e203f7
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Showing 4 changed files with 105 additions and 25 deletions.
2 changes: 2 additions & 0 deletions deps.edn
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Expand Up @@ -22,11 +22,13 @@

:dev
{:extra-paths ["dev"]
:jvm-opts ["-ea" "-Ddatascript.debug" "-Dclojure.main.report=stderr"]
:extra-deps
{io.github.tonsky/duti {:git/sha "fc833a87a8687b67e66281e216eeee1ad6048168"}}}

:test
{:extra-paths ["test"]
:jvm-opts ["-ea" "-Ddatascript.debug" "-Dclojure.main.report=stderr"]
:extra-deps
{org.clojure/clojurescript {:mvn/version "1.10.520"}
metosin/jsonista {:mvn/version "0.3.3"}
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6 changes: 2 additions & 4 deletions dev/user.clj
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Expand Up @@ -7,10 +7,8 @@
(def reload
duti/reload)

(defn -main [& {:as args}]
(set! *warn-on-reflection* true)
(require 'datascript.test)
(duti/start-socket-repl))
(def -main
duti/-main)

(defn test-all []
(duti/test #"datascript\.test\..*"))
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36 changes: 18 additions & 18 deletions src/datascript/db.cljc
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Expand Up @@ -56,7 +56,7 @@
:do `(do ~expr (cond+ ~@rest))
:let `(let ~expr (cond+ ~@rest))
:some `(or ~expr (cond+ ~@rest))
`(if ~test ~expr (cond+ ~@rest))))))
`(util/if+ ~test ~expr (cond+ ~@rest))))))

#?(:clj
(defmacro some-of
Expand Down Expand Up @@ -1354,17 +1354,13 @@
entity
(assoc entity :db/id (auto-tempid))))

(not (sequential? entity))
entity

:let [[op e a v] entity]

(and (= :db/add op) (ref? db a))
(cond
(and (multival? db a) (sequential? v))
(and
(sequential? entity)
:let [[op e a v] entity]
(= :db/add op)
(ref? db a))
(if (and (multival? db a) (sequential? v))
[op e a (assoc-auto-tempids db v)]

:else
[op e a (first (assoc-auto-tempids db [v]))])

:else
Expand Down Expand Up @@ -1664,7 +1660,8 @@
(assoc tempid upserted-eid))
report' (-> initial-report
(assoc :tempids tempids')
(update ::upserted-tempids assoc tempid upserted-eid))]
(update ::upserted-tempids assoc tempid upserted-eid))]
(util/log "retry" tempid "->" upserted-eid)
(transact-tx-data-impl report' es))))

(def builtin-fn?
Expand Down Expand Up @@ -1718,6 +1715,7 @@
initial-es)]
(loop [report initial-report'
es initial-es']
(util/log "transact" es)
(cond+
(empty? es)
(-> report
Expand Down Expand Up @@ -1858,8 +1856,9 @@
(or (= op :db/add) (= op :db/retract))
(not (::internal (meta entity)))
(tuple? db a)
(not= v (resolve-tuple-refs db a v)))
(recur report (cons [op e a (resolve-tuple-refs db a v)] entities))
:let [v' (resolve-tuple-refs db a v)]
(not= v v'))
(recur report (cons [op e a v'] entities))

(tempid? e)
(let [upserted-eid (when (is-attr? db a :db.unique/identity)
Expand All @@ -1873,11 +1872,12 @@
(and
(is-attr? db a :db.unique/identity)
(contains? (::reverse-tempids report) e)
(let [upserted-eid (:e (first (-datoms db :avet a v nil nil)))]
(and e upserted-eid (not= e upserted-eid))))
:let [upserted-eid (:e (first (-datoms db :avet a v nil nil)))]
e
upserted-eid
(not= e upserted-eid))
(let [tempids (get (::reverse-tempids report) e)
tempid (util/find #(not (contains? (::upserted-tempids report) %)) tempids)
upserted-eid (:e (first (-datoms db :avet a v nil nil)))]
tempid (util/find #(not (contains? (::upserted-tempids report) %)) tempids)]
(if tempid
(retry-with-tempid initial-report report initial-es tempid upserted-eid)
(raise "Conflicting upsert: " e " resolves to " upserted-eid " via " entity
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86 changes: 83 additions & 3 deletions src/datascript/util.cljc
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Expand Up @@ -7,9 +7,89 @@
(def ^:dynamic *debug*
false)

(defmacro log [& body]
`(when *debug*
(println ~@body)))
#?(:clj
(defmacro log [& body]
(when (System/getProperty "datascript.debug")
`(when *debug*
(println ~@body)))))

#?(:clj
(def ^:private ^:dynamic *if+-syms))

#?(:clj
(defn- if+-rewrite-cond-impl [cond]
(clojure.core/cond
(empty? cond)
true

(and
(= :let (first cond))
(empty? (second cond)))
(if+-rewrite-cond-impl (nnext cond))

(= :let (first cond))
(let [[var val & rest] (second cond)
sym (gensym)]
(vswap! *if+-syms conj [var sym])
(list 'let [var (list 'clojure.core/vreset! sym val)]
(if+-rewrite-cond-impl
(cons
:let
(cons rest
(nnext cond))))))

:else
(list 'and
(first cond)
(if+-rewrite-cond-impl (next cond))))))

#?(:clj
(defn- if+-rewrite-cond [cond]
(binding [*if+-syms (volatile! [])]
[(if+-rewrite-cond-impl cond) @*if+-syms])))

#?(:clj
(defn- flatten-1 [xs]
(vec
(mapcat identity xs))))

#?(:clj
(defmacro if+
"Allows sharing local variables between condition and then clause.
Use `:let [...]` form (not nested!) inside `and` condition and its bindings
will be visible in later `and` clauses and inside `then` branch:
(if+ (and
(= 1 2)
;; same :let syntax as in doseq/for
:let [x 3
y (+ x 4)]
;; x and y visible downstream
(> y x))
;; then: x and y visible here!
(+ x y 5)
;; else: no x or y
6)"
[cond then else]
(if (and
(seq? cond)
(or
(= 'and (first cond))
(= 'clojure.core/and (first cond))))
(let [[cond' syms] (if+-rewrite-cond (next cond))]
`(let ~(flatten-1
(for [[_ sym] syms]
[sym '(volatile! nil)]))
(if ~cond'
(let ~(flatten-1
(for [[binding sym] syms]
[binding (list 'deref sym)]))
~then)
~else)))
(list 'if cond then else))))

(defn- rand-bits [pow]
(rand-int (bit-shift-left 1 pow)))
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