init

flake.nix

@@ -0,0 +1,62 @@
+{
+  description = "A naersk based rust flake";
+
+  inputs = {
+    utils.url = "github:numtide/flake-utils";
+    naersk = {
+      url = "github:nmattia/naersk";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    index = {
+      flake = false;
+      url = "github:rust-lang/crates.io-index";
+    };
+  };
+
+  outputs = { self, nixpkgs, utils, naersk, index }:
+    let
+      crate = self.lib.crate "bat";
+      pname = crate.latest.name;
+      forPkgs = pkgs:
+        rec {
+        # # `nix build`
+        # packages.${pname} = crate.latest.package { inherit pkgs; };
+
+        # # `nix run`
+        # apps.${pname} = utils.lib.mkApp {
+        #   drv = packages.${pname};
+        # };
+        # defaultApp = apps.${pname};
+        };
+      forSystem = system: forPkgs nixpkgs.legacyPackages."${system}";
+    in
+    (utils.lib.eachDefaultSystem forSystem) // {
+      lib = rec {
+        config = builtins.fromJSON (builtins.readFile "${index}/config.json");
+        crate = name:
+          let
+            dbg = val: builtins.trace val val;
+            strlen = builtins.stringLength;
+            substr = builtins.substring;
+            path = if strlen name < 4 then "${toString (strlen name)}/${substr 0 1 name}/${name}" else "${substr 0 2 name}/${substr 2 2 name}/${name}";
+            build = meta: extra @ { pkgs, ... }:
+              let naersk-lib = naersk.lib."${pkgs.system}"; in
+              naersk-lib.buildPackage ((builtins.removeAttrs extra [ "pkgs" ]) // {
+                root = pkgs.runCommandLocal "unpack-${name}" { buildInputs = [ pkgs.coreutils ]; } ''
+                  mkdir -p $out
+                  tar xvf ${meta.tarball} -C $out --strip-components=1
+                '';
+              });
+            versions = builtins.foldl'
+              (p: i:
+                let meta = i // rec { url = "${config.dl}/${name}/${i.vers}/download"; package = build meta; tarball = builtins.fetchurl { inherit url; sha256 = i.cksum; }; }; in
+                p // { latest = meta; "${i.vers}" = meta; }
+              )
+              { }
+              (map builtins.fromJSON (builtins.filter (s: builtins.isString s && strlen s > 0) (builtins.split "\n" (builtins.readFile "${index}/${path}"))));
+          in
+          versions;
+      };
+    };
+
+}