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(.module:
lux
(lux (control ["p" parser]
["ex" exception (#+ exception:)])
(data ["E" error]))
[// (#+ Tree)]
(// [zipper (#+ Zipper)]))
(type: #export (Parser t a)
(p.Parser (Zipper t) a))
(def: #export (run-zipper zipper parser)
(All [t a] (-> (Zipper t) (Parser t a) (E.Error a)))
(case (p.run zipper parser)
(#E.Success [zipper output])
(#E.Success output)
(#E.Error error)
(#E.Error error)))
(def: #export (run tree parser)
(All [t a] (-> (Tree t) (Parser t a) (E.Error a)))
(run-zipper (zipper.zip tree) parser))
(def: #export value
(All [t] (Parser t t))
(function (_ zipper)
(#E.Success [zipper (zipper.value zipper)])))
(exception: #export cannot-move-further)
(do-template [<name> <direction>]
[(def: #export <name>
(All [t] (Parser t []))
(function (_ zipper)
(let [next (<direction> zipper)]
(if (is? zipper next)
(ex.throw cannot-move-further [])
(#E.Success [next []])))))]
[up zipper.up]
[down zipper.down]
[left zipper.left]
[right zipper.right]
[root zipper.root]
[rightmost zipper.rightmost]
[leftmost zipper.leftmost]
[next zipper.next]
[prev zipper.prev]
)
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