; [q X] -> q(X)
; [q :x] -> q(x)
; [q #(+ 1 2)] -> q(3)

(fn clause [c]
  (match c
    (where [escape expr] (list? c) (= (tostring escape) :hashfn)) `[:const ,expr]
    (where [name & params] (sequence? c)) `[:literal ,(tostring name) ,(icollect [_ param (ipairs params)] (clause param))]
    (where [head & args] (list? c) (sym? head)) (icollect [_ expr (ipairs args) :into [(tostring head)]] (clause expr))
    (where c (list? c)) (icollect [_ val (ipairs c)] (clause val))
    (where v (sym? c)) `[:var ,(tostring v)]
    _ `[:const ,c]))

(fn clauses [...]
  (icollect [_ c (ipairs [...]) :into `(values)] (clause c)))

(fn defrule [s ...] `(: ,s :defrule ,(clauses ...)))

(fn defrules [s ...]
  (icollect [_ rule (ipairs [...]) :into `(do)]
    (defrule s (table.unpack rule))))

(fn query [s ...] `(: ,s :query ,(clauses ...)))
(fn insert [s ...] `(: ,s :insert ,(clauses ...)))
(fn delete [s ...] `(: ,s :delete ,(clauses ...)))
(fn update [s ...] `(: ,s :update ,(clauses ...)))
(fn specify [s ...] `(: ,s :specify ,(clauses ...)))

{: clause : clauses :$ clauses : defrule : defrules : query : insert : delete : update : specify}