Sell book works!

src/book/core.clj

@@ -1,10 +1,17 @@
 (ns book.core
+  (:import [book.PersistentSortedList])
   (:require [book.order]
             [clojure.spec.alpha :as s]
             [clojure.edn :as edn])
   (:gen-class))
 
 
+(defn sorted-list [& keys]
+  (book.PersistentSortedList/create (seq keys)))
+
+(defn sorted-list-by [comparator & keys]
+  (book.PersistentSortedList/create comparator (seq keys)))
+
 
 ;; Let say a book is two collections.  The first called
 ;; sell-book contains all the sell orders.  The second
@@ -12,7 +19,14 @@
 
 (defn create-book [& args]
   (let [cmp #(< (:price %1) (:price %2))]
-    (apply sorted-set-by cmp args)))
+    (apply sorted-list-by cmp args)))
+
+
+(defn sorted-set-rest [s]
+  (print "=>" s)
+  (if (empty? s)
+    s
+    (disj s (first s))))
 
 
 (def book {:sell (create-book) :buy (create-book)})
@@ -65,12 +79,18 @@
       (rest new-book))))
 
 
+(defn leftover-order [order trades]
+  (let [traded-quantity (reduce + (map :book.order/quantity trades))
+        leftover-quantity  (- (:quantity order) traded-quantity)]
+    (when (pos? leftover-quantity)
+      (assoc order :quantity leftover-quantity))))
+
 
 (defn match-buy-order-in-sell-book [sell-book order]
-  (let [trades-1 [(create-trade order (first sell-book))]
-        trades (create-sell-trades order sell-book)
-        new-book (compute-new-sell-book-after-trades sell-book trades)]
-    [trades new-book]))
+  (let [trades (create-sell-trades order sell-book)
+        new-book (compute-new-sell-book-after-trades sell-book trades)
+        new-buy-order (leftover-order order trades)]
+    [trades new-book new-buy-order]))
 
 
 (defn place-buy-order [book order]