Return a magic transformation of an adorned rules-set (rs). The
(i-preds) are the predicates of the intension database. These
default to the predicates within the rules-set.
Source
clojure/contrib/datalog/magic.clj:98
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(defn magic-transform
"Return a magic transformation of an adorned rules-set (rs). The
(i-preds) are the predicates of the intension database. These
default to the predicates within the rules-set."
([rs]
(magic-transform rs (all-predicates rs)))
([rs i-preds]
(let [not-duplicate? (fn [l mh bd]
(or (not (empty? bd))
(not (= (magic-literal l)
mh))))
xr (fn [rs rule]
(let [head (:head rule)
body (:body rule)
mh (magic-literal head)
answer-rule (build-rule head
(concat [mh] body))
step (fn [[rs bd] l]
(if (and (i-preds (literal-predicate l))
(not-duplicate? l mh bd))
(let [nr (build-rule (magic-literal l)
(concat [mh] bd))]
[(conj rs nr) (conj bd l)])
[rs (conj bd l)]))
[nrs _] (reduce step [rs []] body)]
(conj nrs answer-rule)))]
(reduce xr empty-rules-set rs))))
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