Clarify keywords, symbols, maps, sets

ideaboard.txt

@@ -1,5 +1,8 @@
 Concepts / Language Features
 =====
+
+Quoting
+
 new record syntax
 Agents
 Vars

resources/koans.clj

@@ -5,6 +5,9 @@
                       false
                       true
                       true
+                      false
+                      "foo"
+                      "foo"
                       3]}]
 
  ["02_lists" {"__" [1 2 3 4 5
@@ -31,15 +34,14 @@
                    [:butter :and]
                    3]}]
 
- ["04_sets" {"__" [nil
+ ["04_sets" {"__" [[3]
                 3
                 #{1 2 3 4 5}
                 #{1 2 3 4 5}
                 #{2 3}
                 #{1 4}]}]
 
- ["05_maps" {"__" [{}
-                0
+ ["05_maps" {"__" [:b 2
                 1
                 2
                 2

src/koans/01_equalities.clj

@@ -20,5 +20,14 @@
   "Something is not equal to nothing"
   (= __ (not (= 1 nil)))
 
+  "Strings, and keywords, and symbols: oh my!"
+  (= __ (= "foo" :foo 'foo))
+
+  "Make a keyword with your keyboard"
+  (= :foo (keyword __))
+
+  "Symbolism is all around us"
+  (= 'foo (symbol __))
+
   "When things cannot be equal, they must be different"
   (not= :fill-in-the-blank __))

src/koans/04_sets.clj

@@ -1,11 +1,11 @@
 (meditations
-  "You can create a set in two ways"
-  (= #{} (set __))
+  "You can create a set by converting another collection"
+  (= #{3} (set __))
 
-  "They are another important data structure in clojure"
+  "Counting them is like counting other collections"
   (= __ (count #{1 2 3}))
 
-  "Remember that a set is a 'set'"
+  "Remember that a set is a *mathematical* set"
   (= __ (set '(1 1 2 2 3 3 4 4 5 5)))
 
   "You can ask clojure for the union of two sets"

src/koans/05_maps.clj

@@ -1,9 +1,6 @@
 (meditations
-  "There are two ways to create maps"
-  (= __ (hash-map))
-
-  "Maps in clojure associate keys with values"
-  (= __ (count (hash-map)))
+  "Don't get lost when creating a map"
+  (= {:a 1 :b 2} (hash-map :a 1 __ __))
 
   "A value must be supplied for each key"
   (= {:a 1} (hash-map :a __))
@@ -14,7 +11,7 @@
   "You can look up the value for a given key"
   (= __ (get {:a 1 :b 2} :b))
 
-  "Maps can be used as lookup functions"
+  "Maps can be used as functions to do lookups"
   (= __ ({:a 1 :b 2} :a))
 
   "And so can keywords"