This is a learning project.
lhrb.ukanren contains an implementations of the microKanren language as described in this
paper.
To create an (hopefully) easy to understand Clojure implementation I used cons cells instead
of the Clojure sequence abstraction. This yielded an implementation much closer to the original
scheme version.
On the official minikanren site are only two working Clojure implementations and I'm a bit proud that my implementation joins the club alongside core.logic and mullr/micrologic.
lhrb.query contains
- a basic e-a-v-triplet store implementation.
- a datomic inspired query language which uses the
ukanrenimplementation as back-end. (Planned to )
;; basic example
(def db
[[0 :name "Bob"]
[0 :age 40]
[0 :likes "Pizza"]
[1 :name "Alice"]
[1 :likes "Pizza"]
[1 :age 30]
[1 :name "Jutta"]
[2 :age 40]
[2 :likes "Burger"]])
(q {:find [?e]
:where [[?e :likes "Pizza"]
[?e :age (> ?a 30)]]}
db)
=> [[0]]
;; queries against a got db
(require '[lhrb.readcsv :refer [create-got-db]])
(def db (create-got-db))
;; names and nobility of the defending commanders in the battle at Storm's End
(q {:find [?name ?noble]
:where [[?b :battle/location "Storm's End"]
[?b :battle/defender_commander ?name]
[?p :char/Name ?name]
[?p :char/Nobility ?noble]]}
db)
=> [["Renly Baratheon" "nobel"]
["Randyll Tarly" "nobel"]
["Mathis Rowan" "nobel"]
["Cortnay Penrose" "nobel"]
["Loras Tyrell" "nobel"]]
;; battle names where the attacking army size is bigger than 10000
(q {:find [?name ?num]
:where [[?b :battle/name ?name]
[?b :battle/attacker_size (> ?num 10000)]]}
db)
=> [["Battle of Riverrun" 15000]
["Battle of Castle Black" 100000]
["Battle of the Golden Tooth" 15000]
["Battle of the Green Fork" 18000]
["Battle of the Blackwater" 21000]
["Battle of the Fords" 20000]] Rules are currently only supported by using ukanren syntax. Compilation for rules will be supported as soon as I figured out how to schedule the evaluation of recursive rules (currently paths get repeated).
lhrb.readcsvcontains helper to readcsvfiles and also parsing of the got db.lhrb.loadjsoncontains helper to transform basic json to e a v triplets.