Add clojure

.gitignore

@@ -0,0 +1,12 @@
+clojure/resources
+clojure/target
+clojure/classes
+clojure/checkouts
+pom.xml
+pom.xml.asc
+*.jar
+*.class
+*.lein-*
+*.nrepl-port
+*.hgignore
+*.hg/

README.md

@@ -6,7 +6,8 @@ Attempts at solving a gogen puzzle solver in various languages
 
     cd ruby & ruby gogen.rb
     cd go & go run gogen.go
-    cd elixir & elixir gogen.go
+    cd elixir & elixir gogen.exs
+    cd clojure & lein repl # then (-main) I have no idea what I'm doing here
 
 Coming Soon: Clojure
 
@@ -31,3 +32,9 @@ Coming Soon: Clojure
 - The solve function was another interesting issue using the parameters I'd used in previous solutions, namely: `letters_to_find`, map of unfound letters and potential positions, `letters_found` a map of found letters and known positions, and `adjacencies`, a map of letter adjacencies from the word list. The inability to modify variables outside of the loop, i.e. updating the maps - meant that I ended up nesting reduce statements, and implementing my own break/continue pattern using the accumulator tuple, [see here](https://github.com/redroot/gogen/blob/d66047ff2e9e8b9387ee65756ae93287838eabe4/elixir/gogen.exs#L16).
 - One question that came to me while I was doing above if I could do the same with only one map of known letters - possible but I doubt I could use guards since determining if there was still work to do would involve `map_size(Enum.filter(letter_pos_set, fn {k,v} -> length(v) > 1 end))` which I wouldn't be able to write in a guard. Unless I passed the count of remaining letters through as a parameter on each pass. Thats what I did in the `elixir-alt` branch - simplifying the data structures making the reduce accumlator simpler too and only involving a control parameter within the loop once! [See the commit here](https://github.com/redroot/gogen/commit/c9656f92a4460e05a1fb61a0125e809e871e3cf9)
 - But then I realised I didn't even need to control variable now I was doing the length check in the nested reducer! So I managed to make it even simpler, which was the final edition.
+
+#### Clojure
+
+- `lein repl` is super useful, but a pain if there are compilation errors as you have to restart the whole repl to get things to load properly.
+- Errors messaging relating to syntax aren't the most helpful out of the box
+- Simple pure functions are a joy to write, many different ways of doing it, however complicated control flows took a little while longer and doesn't seem as neat, such as print a few blank lines either side of the grid - later I found out you can have multiple statements in a function body with negates the wrapping method I found first. Feels like its best for people who know exactly what they are doing from the get go rather than stepping through an idea.

clojure/project.clj

@@ -0,0 +1,9 @@
+(defproject gogen-clojure "0.1.0-SNAPSHOT"
+  :description "FIXME: write description"
+  :url "http://example.com/FIXME"
+  :license {:name "Eclipse Public License"
+            :url "http://www.eclipse.org/legal/epl-v10.html"}
+  :dependencies [[org.clojure/clojure "1.8.0"]]
+  :main ^:skip-aot gogen-clojure.core
+  :target-path "target/%s"
+  :profiles {:uberjar {:aot :all}})

clojure/src/gogen_clojure/core.clj

@@ -0,0 +1,216 @@
+(ns gogen-clojure.core
+  "A Gogen solver!"
+  (require clojure.string clojure.set)
+  (:gen-class))
+
+(def ^:const text-input-split "#####")
+(def ^:const grid-size 5)
+(def ^:const blank-character "_")
+
+(defn surround-vec
+  [middle end]
+  (into [end]
+    (conj middle end)))
+
+(def all-positions
+  (for [row (range 0 grid-size)
+       col (range 0 grid-size)]
+    [col row]))
+
+(def all-letters
+  (map #(str (char %))
+    (range (int \A) (int \Z))))
+
+(def initial-letter-map
+  (let [letter all-letters]
+    (into {}
+      (map
+        (fn [l] [l,[]])
+        all-letters))))
+
+(defn build-neighbourhood [x y]
+  (let [low-x (max 0 (- x 1))
+        low-y (max 0 (- y 1))
+        high-x (min (- grid-size 1) (+ x 1))
+        high-y (min (- grid-size 1) (+ y 1))
+        x-range (range low-x (+ high-x 1))
+        y-range (range low-y (+ high-y 1))]
+    (map vec
+      (for [a x-range b y-range]
+        (list a b)))))
+
+; optimise this to break to false if it finds any count > 1?
+(defn is-solved?
+  [letters-pos-map]
+  (= (count all-letters)
+     (count
+       (filter
+         #(-> (second %) count (= 1))
+         letters-pos-map))))
+
+(defn puzzle-id []
+  (or (System/getenv "PUZZLE")
+      "1"))
+
+(defn puzzle-raw []
+  (let [id (puzzle-id)]
+    (slurp
+      (str "../examples/" id "-unsolved.txt"))))
+
+(defn raw-from-puzzle []
+  (let [raw (puzzle-raw)]
+    (clojure.string/split raw #"#####")))
+
+(defn extract-grid
+  [grid-raw]
+  (apply mapv vector
+    (mapv #(clojure.string/split % #" ")
+      (clojure.string/split grid-raw #"\n"))))
+
+(defn extract-words
+  [words-raw]
+  (clojure.string/split (clojure.string/trim words-raw) #"\n"))
+
+(defn word-to-letter-pairs
+  [word]
+  (let [word-length (count word)
+        max-index (- word-length 1)]
+    (map
+      (fn [index]
+        (into []
+          [(subs word index (+ index 1))
+           (subs word (+ index 1) (+ index 2))]))
+      (range 0 max-index))))
+
+(defn unique-letter-pairs
+  [words]
+  (distinct
+    (apply concat
+      (map word-to-letter-pairs words))))
+
+(defn extract-adjacencies
+  [words]
+  (let [pairs-list (unique-letter-pairs words)]
+    (reduce
+      (fn [acc pair]
+        (let [a (first pair)
+              b (second pair)
+              a-val (get acc a)
+              b-val (get acc b)]
+          (assoc acc a (conj a-val b)
+                     b (conj b-val a))))
+       initial-letter-map
+       pairs-list)))
+
+(defn extract-known-positions-from-grid
+  [grid]
+  (into {}
+    (remove nil?
+      (apply concat
+        (map-indexed
+          (fn [row_idx row]
+            (map-indexed
+              (fn [col_idx val]
+                (if (= val "_") nil [val [[col_idx row_idx]]])) row))
+          grid)))))
+
+(defn extract-known-positions-from-map
+  [letters-pos-map]
+  (set
+    (mapcat second
+      (filter
+        #(-> (second %) count (= 1))
+        letters-pos-map))))
+
+(defn extract-letters-pos-map
+  [grid]
+  (let [known-letters-pos-map (extract-known-positions-from-grid grid)
+        known-letters-positions (set (map first (vals known-letters-pos-map)))
+        unknown-positions (clojure.set/difference (set all-positions) known-letters-positions)]
+    (into {}
+      (map
+        (fn [[letter v]]
+          (let [known-val (get known-letters-pos-map letter)]
+            (if (nil? known-val) [letter unknown-positions] [letter (set known-val)])))
+        initial-letter-map))))
+
+; we can have statements per function, fix this
+(defn print-grid
+  [grid]
+  (map
+    (fn [l] (apply println l))
+      (vec
+        (map
+          (fn [pos] (clojure.string/join "" pos))
+          grid))))
+
+(defn data-from-puzzle []
+  (let [[grid-raw words-raw] (raw-from-puzzle)
+        grid (extract-grid grid-raw)
+        words (extract-words words-raw)]
+    (into []
+          [grid
+           (extract-adjacencies words)
+           (extract-letters-pos-map grid)])))
+
+(defn build-neighbourhood-set-from-pos-list
+  [pos-list]
+  (set
+    (distinct ; uniq positible identity
+      (mapcat identity ; flatten 1 layer
+        (map
+          (fn
+            [pos]
+            (build-neighbourhood (first pos) (second pos)))
+          pos-list)))))
+
+(defn updated-value-from-adjacencies
+  [letter-positions adj-letter-positions known-positions]
+  (let [neighbour-set (build-neighbourhood-set-from-pos-list adj-letter-positions)]
+    (clojure.set/intersection
+      letter-positions
+      (clojure.set/difference neighbour-set known-positions))))
+
+(defn solve-step
+  [adjacencies letters-pos-map]
+  (reduce
+    (fn
+      [acc [letter _]]
+      (reduce
+        (fn [inner-map adj-letter]
+          (let [inner-map-letter-ps (get inner-map letter)
+                inner-map-adj-letter-ps (get inner-map adj-letter)
+                known-positions (extract-known-positions-from-map inner-map)
+                neighbour-set (build-neighbourhood-set-from-pos-list inner-map-adj-letter-ps)
+                updated-value (updated-value-from-adjacencies inner-map-letter-ps inner-map-adj-letter-ps known-positions)]
+                (if (= (count inner-map-letter-ps) 1)
+                  inner-map ; exit early
+                  (assoc inner-map letter updated-value))))
+        acc
+        (get adjacencies letter)))
+    letters-pos-map
+    letters-pos-map))
+
+(defn solve
+  [adjacencies letters-pos-map]
+  (if (is-solved? letters-pos-map)
+      letters-pos-map
+      (recur adjacencies (solve-step adjacencies letters-pos-map))))
+
+(defn update-grid
+  [grid letters-pos-map]
+  (reduce
+    (fn
+      [new-grid [letter pos-map]]
+      (let [[x y] (first pos-map)]
+        (update-in new-grid [y x] (fn [_] letter))))
+    grid
+    letters-pos-map))
+
+(defn -main
+  "Main entry point to solving Gogen puzzles"
+  [& args]
+  (let [[grid adjacencies letters-pos-map] (data-from-puzzle)]
+    (print-grid
+      (update-grid grid
+        (solve adjacencies letters-pos-map)))))