From 9b9005448b2c56ef197a87d75a4fe6019a814f30 Mon Sep 17 00:00:00 2001
From: "Michael S. Klishin" <michael@novemberain.com>
Date: Tue, 6 Mar 2012 19:38:40 +0400
Subject: [PATCH] Implement monger.internal.fn/expand-all-with

---
 src/monger/internal/fn.clj       | 46 +++++++++++++++++++++-----------
 test/monger/test/internal/fn.clj |  9 ++++++-
 2 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/src/monger/internal/fn.clj b/src/monger/internal/fn.clj
index 04f3690..46b4a6c 100644
--- a/src/monger/internal/fn.clj
+++ b/src/monger/internal/fn.clj
@@ -19,41 +19,55 @@
   (into {} (for [[k v] m]
              [k (f v)])))
 
-
 ;;
 ;; API
 ;;
 
+(defn fpartial
+  "Like clojure.core/partial but prepopulates last N arguments (first is passed in later)"
+  [f & args]
+  (fn [arg & more] (apply f arg (concat args more))))
+
 (defprotocol IFNExpansion
-  (expand-all [x] "Invokes functions, recursively expands maps, evaluates all other values to themselves"))
+  (expand-all      [x] "Replaces functions with their invocation results, recursively expands maps, evaluates all other values to themselves")
+  (expand-all-with [x f] "Replaces functions with their invocation results that function f is applied to, recursively expands maps, evaluates all other values to themselves"))
 
 (extend-protocol IFNExpansion
   java.lang.Integer
-  (expand-all [i] i)
+  (expand-all      [i]   i)
+  (expand-all-with [i f] i)
 
   java.lang.Long
-  (expand-all [l] l)
+  (expand-all      [l] l)
+  (expand-all-with [l f] l)
 
   java.lang.String
-  (expand-all [s] s)
+  (expand-all      [s] s)
+  (expand-all-with [s f] s)
 
   java.lang.Float
-  (expand-all [f] f)
+  (expand-all      [fl] fl)
+  (expand-all-with [fl f] fl)
 
   java.lang.Double
-  (expand-all [d] d)
+  (expand-all      [d] d)
+  (expand-all-with [d f] d)
 
-  java.util.Map
-  (expand-all [m] (apply-to-values m expand-all))
+  ;; maps are also functions, so be careful here. MK.
+  clojure.lang.IPersistentMap
+  (expand-all      [m]   (apply-to-values m expand-all))
+  (expand-all-with [m f] (apply-to-values m (fpartial expand-all-with f)))
 
   clojure.lang.PersistentVector
-  (expand-all [v] (map expand-all v))
+  (expand-all      [v]   (map expand-all v))
+  (expand-all-with [v f] (map (fpartial expand-all-with f) v))
 
-  clojure.lang.APersistentMap
-  (expand-all [m] (apply-to-values m expand-all))
-
-  clojure.lang.IFn
-  (expand-all [f] (f))
+  ;; this distinguishes functions from maps, sets and so on, which are also
+  ;; clojure.lang.AFn subclasses. MK.
+  clojure.lang.AFunction
+  (expand-all      [f]          (f))
+  (expand-all-with [f expander] (expander (f)))
 
   Object
-  (expand-all [x] x))
+  (expand-all      [x] x)
+  (expand-all-with [x f] x))
diff --git a/test/monger/test/internal/fn.clj b/test/monger/test/internal/fn.clj
index 62064bf..4d7c72b 100644
--- a/test/monger/test/internal/fn.clj
+++ b/test/monger/test/internal/fn.clj
@@ -3,7 +3,7 @@
         [monger.internal.fn]))
 
 
-(deftest test-recursive-function-values-expansion
+(deftest test-expand-all
   (are [i o] (is (= (expand-all i) o))
        { :int (fn [] 1) :str "Clojure" :float (Float/valueOf 11.0)  } { :int 1 :str "Clojure" :float (Float/valueOf 11.0 )}
        { :long (fn [] (Long/valueOf 11)) } { :long (Long/valueOf 11) }
@@ -36,3 +36,10 @@
                 :nested { :a { :b { :c "d" } } }
                 }
         }))
+
+(deftest test-expand-all-with
+  (let [expander-fn (fn [v]
+                      (* 3 v))]
+  (are [i o] (is (= (expand-all-with i expander-fn) o))
+       { :a 1 :int (fn [] 3) } { :a 1 :int 9 }
+       { :v [(fn [] 1) (fn [] 11)] :m { :inner (fn [] 3) } :s "Clojure" } { :v [3 33] :m { :inner 9 } :s "Clojure" })))