feature(core): more hash table functions

2 files changed, 50 insertions, 2 deletions

diff --git a/cljlib.fnl b/cljlib.fnl
index f400340..f649b1a 100644
--- a/cljlib.fnl
+++ b/cljlib.fnl
@@ -906,7 +906,7 @@ use."
             res))))))
 
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Hash map extras ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Hash table extras ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (fn* core.assoc
   "Associate key `k` with value `v` in `tbl`."
@@ -955,6 +955,36 @@ found in the table."
        (set res not-found)))
    res))
 
+(fn* core.keys
+  "Returns a sequence of the table's keys, in the same order as [`seq`](#seq)."
+  [tbl]
+  (let [res []]
+    (each [k _ (pairs tbl)]
+      (insert res k))
+    res))
+
+(fn* core.vals
+  "Returns a sequence of the table's values, in the same order as [`seq`](#seq)."
+  [tbl]
+  (let [res []]
+    (each [_ v (pairs tbl)]
+      (insert res v))
+    res))
+
+(fn* core.find
+  "Returns the map entry for `key`, or `nil` if key not present."
+  [tbl key]
+  (when-some [v (. tbl key)]
+    [key v]))
+
+(fn* core.dissoc
+  "Remove `key` from table `tbl`."
+  ([tbl] tbl)
+  ([tbl key]
+   (doto tbl (tset key nil)))
+  ([tbl key & keys]
+   (apply dissoc (dissoc tbl key) keys)))
+
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Multimethods ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
diff --git a/tests/core.fnl b/tests/core.fnl
index 1921a05..d323a07 100644
--- a/tests/core.fnl
+++ b/tests/core.fnl
@@ -423,7 +423,25 @@
     (assert-not (pcall assoc))
     (assert-not (pcall assoc {}))
     (assert-eq (assoc {} :a 1) {:a 1})
-    (assert-eq (assoc {} :a 1 :b 2 :c 3 :d 4) {:a 1 :b 2 :c 3 :d 4})))
+    (assert-eq (assoc {} :a 1 :b 2 :c 3 :d 4) {:a 1 :b 2 :c 3 :d 4}))
+
+  (testing "dissoc"
+    (assert-not (pcall dissoc))
+    (assert-eq (dissoc {}) {})
+    (assert-eq (dissoc {:a 1 :b 2} :b) {:a 1})
+    (assert-eq (dissoc {:a 1 :b 2 :c 3} :a :c) {:b 2}))
+
+  (testing "find, keys and vals"
+    (assert-not (pcall keys))
+    (assert-not (pcall keys {} {} {}))
+    (assert-not (pcall vals))
+    (assert-not (pcall vals {} {} {}))
+    (assert-not (pcall find))
+    (assert-not (pcall find {} {} {}))
+    (assert-eq (keys {:a 1 :b 2 :c 3}) (hash-set :a :b :c))
+    (assert-eq (vals {:a 1 :b 2 :c 3}) (hash-set 1 2 3))
+    (assert-eq (find {:a 1 :b 2 :c 3} :c) [:c 3])
+    (assert-eq (find {:a 1 :b 2 :c 3} :d) nil)))
 
 (deftest function-manipulation
   (testing "constantly"