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(defne nqueenso [l n]
  ([() _])                    ;; queen list empty, s#
  ([[[x y] . t] _]            ;; match/destruct head.tail, ignore n
     (nqueenso t n)
     (membero x (range n))
     (safeo [x y] t)))

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(def subo
  (fn ([x y r]
        (conde
          [(== x 0) (== y 0) (== r 0)]
          [(== x 0) (== y 1) (== r -1)]
          [(== x 1) (== y 0) (== r 1)]
          [(== x 1) (== y 1) (== r 0)]))))

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;; Datomic example code
(use '[datomic.api :only (db q) :as d])

;; ?answer binds a scalar
(q '[:find ?answer :in ?answer]
   42)

;; of course you can bind more than one of anything
(q '[:find ?last ?first :in ?last ?first]
   "Doe" "John")

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(ns tut.hello
  (:use [datomic.api :only [db q] :as d]))

(defn add-get-user [uri]
  (d/create-database uri)
  (let [conn (d/connect uri)
        dbase (d/db conn)]
    (d/transact conn [{:db/id #db/id [:db.part/user]
                       :db/doc "Hello World!"}])

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(ns logevt-cl
  (:refer-clojure :exclude [==])
  (:use [clojure.core.logic])
  (:import [java.util UUID]))

(defrel id-name ^:index id ^:index name)
(defrel id-time ^:index id ^:index time)
(defrel id-op ^:index id ^:index op)
(defrel id-cat ^:index id ^:index cat)
(defrel id-parent-op ^:index id ^:index parent-op)

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(let [id (java.util.UUID/randomUUID)]
  (emit-timed {:id id :op :add})
  (emit-timed {:id id :cat :backend :op :send})
  (emit-timed {:id id :cat :backend :op :ack :parent-op :send})
  (emit-timed {:id id :cat :backend :op :sub :parent-op :send})
  (emit-timed {:id id :cat :distribution :op :contribute})
  (emit-timed {:id id :cat :distribution :op :chain-contribute})
  (emit-timed {:id id :cat :distribution :op :chain-event :parent-op :contribute})
  (emit-timed {:id id :op :done :parent-op :add})))

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(defn draw-line!
  "Draws a line (bresenham algorithm)"
  [color [c0 r0] [c1 r1] screen]
  (let [dc (- c1 c0)
        dr (- r1 r0)
        derr (Math/abs (/ dr dc))]
    (loop [err derr
           r r0
           c c0]
      (when (< c c1)

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;; example from ScalaCheck

(ns string-tests
  (:use clojure.test.generative))

(defspec startsWith
  (partial map identity)
  [^string a ^string b]
  (assert (.startsWith (str a b) a)))

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;; Alan Dipert BFC

(defn bfc [program]
  (let [allowed #{\+ \- \< \> \[ \] \.}
        src (->> program (filter allowed)
                 (interpose \space) (apply str))
        fns (zipmap '(- + < > . ?) (repeatedly gensym))]
    (letfn [(bfc* [s]
              (if (vector? s)
                `(while (not (~(fns '?))) ~@(map bfc* s))

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(ns monads
  (:require clojure.set))

(declare ^:dynamic return
         ^:dynamic bind)

(defn lift-inc [v]
  (return (inc v)))

(defn m-add [mv n]