52 lines
1.4 KiB
Plaintext
52 lines
1.4 KiB
Plaintext
include "List.aes"
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include "Option.aes"
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include "Pair.aes"
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namespace Set =
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record set('a) = { to_map : map('a, unit) }
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function new() : set('a) =
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{ to_map = {} }
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function member(e : 'a, s : set('a)) : bool =
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Map.member(e, s.to_map)
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function insert(e : 'a, s : set('a)) : set('a) =
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{ to_map = s.to_map{[e] = ()} }
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function delete(e : 'a, s : set('a)) : set('a) =
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{ to_map = Map.delete(e, s.to_map) }
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function size(s : set('a)) : int =
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Map.size(s.to_map)
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function to_list(s : set('a)) : list('a) =
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List.map(Pair.fst, Map.to_list(s.to_map))
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function from_list(l : list('a)) : set('a) =
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{ to_map = Map.from_list(List.map((x) => (x, ()), l)) }
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function filter(p : 'a => bool, s : set('a)) : set('a) =
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from_list(List.filter(p, to_list(s)))
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function fold(f : ('a, 'b) => 'b, acc : 'b, l : set('a)) : 'b =
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List.foldr(f, acc, to_list(l))
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function subtract(s1 : set('a), s2 : set('a)) : set('a) =
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filter((x) => !member(x, s2), s1)
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function intersection(s1 : set('a), s2 : set('a)) : set('a) =
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filter((x) => member(x, s2), s1)
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function intersection_list(sets : list(set('a))) : set('a) =
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List.foldr(
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intersection,
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Option.default(new(), List.first(sets)),
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Option.default([], List.tail(sets)))
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function union(s1 : set('a), s2 : set('a)) : set('a) =
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from_list(to_list(s1) ++ to_list(s2))
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function union_list(sets : list(set('a))) : set('a) =
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List.foldr(union, new(), sets)
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