An example of Clojure core.logic that finds map that match a certain structure. Both functions are equilivent but one uses list comprehension and the other uses core.logic

featurec.clj

(ns logicfun.core
  ;(:refer-clojure :exclude [==])
  (:use [clojure.core.logic :rename {== ?==}]))

(def data [
           {:id 1 :type :t1 :name "one" :other1 :o2}
           {:id 2 :type :t2 :name "two" :other2 :o1 :another :ao2}
           {:id 3 :type :t3 :name "three" :other2 :o1 :another :ao1}
           ])

(defn map-test-logic []
  (run* [q] 
       (fresh [?id ?type ?name ?pm] 
              (membero ?type [:t1 :t2])
              (?== q [?id ?name])
              (featurec ?pm  {:id ?id :type ?type :name ?name} )
              (membero ?pm data))))

(defn map-test []
  (for [{:keys [id type name]} data :when (#{:t1 :t2} type)]
    [id name]))