34 lines
736 B
Nix
34 lines
736 B
Nix
{ lib, ... }:
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let
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inherit (lib) filter foldl';
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in
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{
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# Count the number of appararitions of each value in a list.
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#
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# countValues ::
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# [ any ] -> ({ any = int; })
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countValues =
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let
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addToCount = acc: x:
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let
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v = toString x;
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in
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acc // { ${v} = (acc.${v} or 0) + 1; };
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in
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foldl' addToCount { };
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# Filter a list using a predicate function after applying a map.
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#
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# mapFilter ::
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# (value -> bool)
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# (any -> value)
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# [ any ]
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mapFilter = pred: f: attrs: filter pred (map f attrs);
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# Transform a nullable value into a list of zero/one element.
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#
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# nullableToList ::
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# (nullable a) -> [ a ]
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nullableToList = x: if x != null then [ x ] else [ ];
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}
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