Add time macro

sci

@@ -1 +1 @@
-Subproject commit 51961ef24817bb2e33a75946a74c493eac9bcbcf
+Subproject commit 689a4d018f8f729ff79408b6a43aed631138b19a

src/babashka/impl/clojure/core.clj

@@ -6,6 +6,15 @@
 (defn locking* [form bindings v f & args]
   (apply @#'locking/locking form bindings v f args))
 
+(defn time*
+  "Evaluates expr and prints the time it took.  Returns the value of
+  expr."
+  [_ _ expr]
+  `(let [start# (. System (nanoTime))
+         ret# ~expr]
+     (prn (str "Elapsed time: " (/ (double (- (. System (nanoTime)) start#)) 1000000.0) " msecs"))
+     ret#))
+
 (def core-extras
   {'file-seq file-seq
    'agent agent
@@ -18,5 +27,6 @@
    'shutdown-agents shutdown-agents
    'slurp slurp
    'spit spit
+   'time (with-meta time* {:sci/macro true})
    'Throwable->map Throwable->map
    'compare-and-set! compare-and-set!})