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Update comment in cc.cljc.

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Richard Newman 2016-09-29 15:49:30 -07:00
parent 6ab93208cb
commit a7d6a37cfc
1 changed files with 7 additions and 6 deletions
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13
src/common/datomish/query/cc.cljc
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@ -37,18 +37,19 @@
;; bind it to the outer variables, or adds simple WHERE clauses to the outer
;; clause.
;; - `not-join` is similar, but with explicit binding.
;; - `or` turns into a collection of UNIONs inside a subquery, or a simple
;; alternation.
;; `or`'s documentation states that all clauses must include the same vars,
;; but that's an over-simplification: all clauses must refer to the external
;; unification vars.
;; The entire UNION-set is JOINed to any surrounding expressions per the `rule-vars`
;; clause, or the intersection of the vars in the two sides of the JOIN.
;;
;; Not yet done:
;; - Function clauses with bindings turn into:
;; * Subqueries. Perhaps less efficient? Certainly clearer.
;; * Projection expressions, if only used for output.
;; * Inline expressions?
;; - `or` turns into a collection of UNIONs inside a subquery.
;; `or`'s documentation states that all clauses must include the same vars,
;; but that's an over-simplification: all clauses must refer to the external
;; unification vars.
;; The entire UNION-set is JOINed to any surrounding expressions per the `rule-vars`
;; clause, or the intersection of the vars in the two sides of the JOIN.
;;---------------------------------------------------------------------------------------
;;
;; `from` is a list of [source alias] pairs, suitable for passing to honeysql.