bot.clj

(ns pw.bot
  (:gen-class :main true :prefix "-")
  (:use [clojure.string :only (trim split-lines)]
        pw.planetwars))

;; Helpers for your bot
(defn my-strongest-planet
  [pw]
  ((first (sort-by #(> (:num-ships %1) (:num-ships %2))
                   (my-planets pw))) :planet-id))

(defn weakest-enemy-planet
  [pw]
  ((first (sort-by #(< (:num-ships %1) (:num-ships %2))
                   (enemy-planets pw))) :planet-id))

(defn ihalf [x] (int (/ x 2)))

;; Your Robot
(defn do-turn [pw]
  (cond
   ;; Do nothing if a fleet is in flight
   (pos? (count (my-fleets pw))) nil
   ;; Else send half your ships from your strongest planets
   ;; to your enemy's weakest planet
   :else (let [source (my-strongest-planet pw) 
               dest (weakest-enemy-planet pw)]
           (if (and (pos? source) (pos? dest))
             (issue-order source dest
                          (ihalf ((get-planet pw source) :num-ships)))))))


;; utility functions
(defn- go? [s] (= (apply str (take 2 s)) "go"))
(defn- take-turn
  [f pw]
  (f (parse-game-state pw)) ;; run your bot (f) on parsed pw
  (finish-turn)) ;; say go

;; Main IO loop
(defn -main [& args]
  (try
      (loop [line (read-line) pw ""]
        (cond (go? line) (if-not (empty? pw)
                           (do
                             (take-turn do-turn pw)
                             (recur (read-line) ""))
                           (do
                             (finish-turn)
                             (recur (read-line) "")))
              :else (recur (read-line)
                           (apply str (concat pw line "\n")))))
      (catch Exception e
          (java.lang.System/exit 1)))
    (java.lang.System/exit 0))

project.clj

(defproject clj-pwars "1.0.0-SNAPSHOT"
  :description "FIXME: write"
  :dependencies [[org.clojure/clojure "1.2.0"]
                 [org.clojure/clojure-contrib "1.2.0"]]
  :dev-dependencies [[swank-clojure "1.2.1"]]
  :aot [pw.bot pw.bot pw.planetwars]
  :main pw.bot
)