diff options
| -rw-r--r-- | by-name-overlay.nix | 149 |
1 files changed, 105 insertions, 44 deletions
diff --git a/by-name-overlay.nix b/by-name-overlay.nix index 3e52e64..0395492 100644 --- a/by-name-overlay.nix +++ b/by-name-overlay.nix @@ -12,22 +12,21 @@ # This file should not depend on `pkgs` and thus not use `lib`. { baseDirectory, - fileName, + fileName ? null, + fileRegex ? null, finalizeFunction ? name: value: value, useShards ? true, -}: let - # Takes a list of attrs as input and returns one merged attr set. - flattenAttrs = list: - if builtins.isList list - then - builtins.foldl' (acc: elem: - if builtins.isList elem - # Merging them with `//` is okay here, as we can be sure that the attr names are - # unique (they were separate dictionary after all) - then acc // (flattenAttrs elem) - else acc // elem) {} - list - else list; +}: +assert fileName == null -> fileRegex != null; +assert fileRegex == null -> fileName != null; let + finalFileRegex = + if fileRegex == null + then "^${escapeRegex fileName}$" + else fileRegex; + fileDisplay = + if fileName == null + then "matching ${fileRegex}" + else fileName; # From nixpkgs/lib {{{ # These functions are taken straight out of the `nixpkgs/lib`. @@ -36,6 +35,12 @@ mapAttrsToList = f: attrs: builtins.map (name: f name attrs.${name}) (builtins.attrNames attrs); + stringToCharacters = s: builtins.genList (p: builtins.substring p 1 s) (builtins.stringLength s); + escape = list: builtins.replaceStrings list (map (c: "\\${c}") list); + escapeRegex = escape (stringToCharacters "\\[{()^$?*+|."); + + mapAttrs' = f: set: builtins.listToAttrs (map (attr: f attr set.${attr}) (builtins.attrNames set)); + nameValuePair = name: value: {inherit name value;}; filterAttrs = pred: set: builtins.listToAttrs (builtins.concatMap (name: let @@ -46,39 +51,95 @@ else []) (builtins.attrNames set)); # }}} - # Module files for a single shard - # Type: String -> String -> ListOf Path - namesForShard = shard: type: - if type != "directory" - then warn "Ignored non-directory, whilst importing by-name directory (${fileName}): '${shard}'" {} - else if useShards - then namesForElement shard type - else namesForElement "." type; + rawByName = { + baseDirectory, + finalFileRegex, + fileDisplay, + finalizeFunction, + useShards, + }: let + # Takes a list of attrs as input and returns one merged attr set. + flattenAttrs = list: + if builtins.isList list + then + builtins.foldl' (acc: elem: + if builtins.isList elem + # Merging them with `//` is okay here, as we can be sure that the attr names are + # unique (they were separate dictionary after all) + then acc // (flattenAttrs elem) + else acc // elem) {} + list + else list; - namesForElement = shard: _type: let - mkPath = name: type: let - path = baseDirectory + "/${shard}/${name}" + "/${fileName}"; + # Module files for a single shard + # Type: String -> String -> ListOf Path + namesForShard = shard: type: + if type != "directory" + then warn "Ignored non-directory, whilst importing by-name directory (${fileDisplay}): '${shard}'" {} + else if useShards + then namesForElementShard shard type + else namesForElementDirect shard type; + + # Type: String -> String -> ListOf Path + mkPath = name: toplevelType: let + rawPath = baseDirectory + "/${name}"; + paths = filterAttrs (_: v: v != null) (mapAttrs' (name: value: + if builtins.match finalFileRegex name != null + then nameValuePair name value + else nameValuePair name null) (builtins.readDir rawPath)); + + checkPath = path: type: + if builtins.pathExists "${rawPath}/${path}" + then + if toplevelType != "directory" + then + # The `namesForShard` function should have already printed a warning. + [null] + else path + else warn "'${builtins.toString path}' does not exist. Skipped" null; in - if builtins.pathExists path + if toplevelType != "directory" then - if type != "directory" - then - # The `namesForShard` function should have already printed a warning. - null - else path - else warn "'${builtins.toString path}' does not exist. Skipped" null; + # The `namesForShard` function should have already printed a warning. + [null] + else if (builtins.attrValues paths) == [] + then warn "'${fileDisplay}' did not match anything in ${rawPath}. Skipped" [null] + else mapAttrsToList checkPath paths; + + # Type: String -> String -> AttrSet + namesForElementShard = shard: _type: + filterAttrs (name: value: value != null) + (builtins.mapAttrs + mkPath + (builtins.readDir (baseDirectory + "/${shard}"))); + + # Type: String -> String -> AttrSet + namesForElementDirect = name: type: {"${name}" = builtins.filter (value: value != null) (mkPath name type);}; + + # A list of all paths. + files = flattenAttrs (mapAttrsToList namesForShard (builtins.readDir baseDirectory)); + output = + builtins.mapAttrs + finalizeFunction + files; in - filterAttrs (name: value: value != null) - (builtins.mapAttrs - mkPath - (builtins.readDir (baseDirectory + "/${shard}"))); + output; + + firstPass = rawByName { + inherit + baseDirectory + finalFileRegex + fileDisplay + finalizeFunction + useShards + ; + }; - # A list of all module paths. - # These can the be simply injected into `import` - files = flattenAttrs (mapAttrsToList namesForShard (builtins.readDir baseDirectory)); - output = - builtins.mapAttrs - finalizeFunction - files; + secondPass = + if fileName != null + then + builtins.mapAttrs (name: value: builtins.head value) + (filterAttrs (_: value: value != []) firstPass) + else firstPass; in - output + secondPass |