50 lines
1.5 KiB
Nix
50 lines
1.5 KiB
Nix
{ lib ? import <nixpkgs/lib> }:
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let
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inherit (builtins) baseNameOf dirOf length genList pathExists;
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inherit (lib) take splitString concatStringsSep last foldl foldr head
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tail singleton removePrefix hasSuffix removeSuffix flatten crossLists reverseList;
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butlast = list: take (length list - 1) list;
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doFileSuffix = "do";
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genPatterns = path: let
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fn = baseNameOf path;
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in (map (x: "default." + x)
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(foldr (a: b: let x = (head b); in [ (a + "." + x) ] ++ b)
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[ doFileSuffix ]
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(tail (splitString "." fn))));
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searchPath = path:
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let
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pathlist = (splitString "/" path);
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pat = (last pathlist);
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doFile = path + "." + doFileSuffix;
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patlist = genPatterns pat;
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foldedpaths = foldr (a: b:
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let
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h = if length b == 0 then "" else head b;
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in [ (h + a + "/") ] ++ b) [] (tail (reverseList pathlist));
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pths = crossLists (p: pat: p + pat) [ foldedpaths patlist ];
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in [ doFile ] ++ pths;
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whichdo = path: let
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pathlist = searchPath path;
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in foldl (res: p: if res == "" then if pathExists p then p else res else res) "" pathlist;
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d1 = path: pat: let
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dir = (dirOf pat) + "/";
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in removePrefix dir path;
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d2 = path: pat: let
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dir = (dirOf pat) + "/";
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_path = removePrefix dir path;
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_pat = removeSuffix ".${doFileSuffix}" (removePrefix "${dir}default" pat);
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_out = removeSuffix _pat _path;
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in if _out == "" then _path else _out;
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self = {
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inherit searchPath doFileSuffix whichdo d1 d2;
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};
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in self
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