diff --git a/c_.nix b/c_.nix
new file mode 100644
index 0000000..8e787e9
--- /dev/null
+++ b/c_.nix
@@ -0,0 +1,100 @@
+# a small helper that only builds on top of builtins functions
+{src}@inputs:
+builtins // (let 
+formatSecondsSinceEpoch = t:
+let
+rem = x: y: x - x / y * y;
+days = t / 86400;
+secondsInDay = rem t 86400;
+hours = secondsInDay / 3600;
+minutes = (rem secondsInDay 3600) / 60;
+seconds = rem t 60;
+
+# Courtesy of https://stackoverflow.com/a/32158604.
+z = days + 719468;
+era = (if z >= 0 then z else z - 146096) / 146097;
+doe = z - era * 146097;
+yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
+y = yoe + era * 400;
+doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+mp = (5 * doy + 2) / 153;
+d = doy - (153 * mp + 2) / 5 + 1;
+m = mp + (if mp < 10 then 3 else -9);
+y' = y + (if m <= 2 then 1 else 0);
+
+pad = s: if builtins.stringLength s < 2 then "0" + s else s;
+in "${toString y'}${pad (toString m)}${pad (toString d)}${pad (toString hours)}"
++ "${pad (toString minutes)}${pad (toString seconds)}";
+
+fetchTree =
+# this is the value of flake.lock#lock.nodes.${input_name}.locked
+{type
+, host? ""
+, owner? ""
+, repo? ""
+, rev? ""
+, submodules? ""
+, path? ""
+, narHash? null
+, lastModified? 0
+}@info:
+if info.type == "github" then
+{ outPath =
+  fetchTarball
+    ({ url = "https://api.${info.host or "github.com"}/repos/"
+     + "${info.owner}/${info.repo}/tarball/${info.rev}"; }
+     // (if info ? narHash then { sha256 = info.narHash; } else {})
+    );
+  rev = info.rev;
+  shortRev = builtins.substring 0 7 info.rev;
+  lastModified = info.lastModified;
+  lastModifiedDate = formatSecondsSinceEpoch info.lastModified;
+  narHash = info.narHash;
+}
+else if info.type == "git" then
+{ outPath =
+  builtins.fetchGit
+    ({ url = info.url; }
+     // (if info ? rev then { inherit (info) rev; } else {})
+     // (if info ? ref then { inherit (info) ref; } else {})
+     // (if info ? submodules then { inherit (info) submodules; } else {})
+    );
+  lastModified = info.lastModified;
+  lastModifiedDate = formatSecondsSinceEpoch info.lastModified;
+  narHash = info.narHash;
+} // (if info ? rev then {
+rev = info.rev;
+shortRev = builtins.substring 0 7 info.rev;
+} else {
+})
+else if info.type == "path" then
+{ outPath = builtins.path { 
+  path = if builtins.substring 0 1 info.path != "/"
+    then src + ("/" + info.path)  # make this absolute path by prepending ./
+    else info.path; # it's already an absolute path
+                          };
+narHash = info.narHash;
+}
+else if info.type == "tarball" then
+{ outPath =
+  fetchTarball
+    ({ inherit (info) url; }
+     // (if info ? narHash then { sha256 = info.narHash; } else {})
+    );
+}
+else if info.type == "gitlab" then
+{ inherit (info) rev narHash lastModified;
+  outPath =
+    fetchTarball
+    ({ url = "https://${info.host or "gitlab.com"}/api/v4/projects/${info.owner}%2F${info.repo}/repository/archive.tar.gz?sha=${info.rev}"; }
+     // (if info ? narHash then { sha256 = info.narHash; } else {})
+    );
+  shortRev = builtins.substring 0 7 info.rev;
+}
+else
+# FIXME: add Mercurial, tarball inputs.
+throw "flake input has unsupported input type '${info.type}'";
+in {
+  inherit fetchTree;
+})
+
diff --git a/default.nix b/default.nix
index 3fa0b39..9004ce7 100644
--- a/default.nix
+++ b/default.nix
@@ -1,11 +1,11 @@
 # We use top-level nix-flake, so default.nix is basically just a wrapper around ./flake.nix
 (import
   (
-    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
-    fetchTarball {
-      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
-      sha256 = lock.nodes.flake-compat.locked.narHash;
-    }
+    let 
+      lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+      c_ = import ./c_.nix {src = ./.;};
+    in
+    c_.fetchTree lock.nodes.flake-compat.locked
   )
   { src = ./.; }
 ).defaultNix
diff --git a/flake.lock b/flake.lock
index 277ba5c..112842d 100644
--- a/flake.lock
+++ b/flake.lock
@@ -156,11 +156,11 @@
       },
       "locked": {
         "dir": "contrib",
-        "lastModified": 1673683108,
-        "narHash": "sha256-zg1W14wyrOCKiTkXU+nGHf/EfqX6wtcUWcMo4O/Q6nY=",
+        "lastModified": 1673746461,
+        "narHash": "sha256-Y21pbVNlPWPokXFbngSahnxeCff0LX+LKdDktEBIVm4=",
         "owner": "neovim",
         "repo": "neovim",
-        "rev": "e89c39d6f016a4140293755250e968e839009617",
+        "rev": "6134c1e8a39a5e61d0593613343a5923a86e3545",
         "type": "github"
       },
       "original": {
@@ -177,11 +177,11 @@
         "nixpkgs": "nixpkgs"
       },
       "locked": {
-        "lastModified": 1673684013,
-        "narHash": "sha256-ljfG17g9K5sl7DGounCwOIfQLOGzXF0ffuDGxo3UN1E=",
+        "lastModified": 1673770422,
+        "narHash": "sha256-hYVEUzvqobxAM2FZfWTrTLKKNfkOSfsm0uGqNoSiIvw=",
         "owner": "nix-community",
         "repo": "neovim-nightly-overlay",
-        "rev": "85b0900729bffa5e0d1817bbc6f024916dc1f38e",
+        "rev": "fd8e5953cfeada345d7daeedce6ab0919f1284d4",
         "type": "github"
       },
       "original": {
@@ -197,11 +197,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1673365945,
-        "narHash": "sha256-/duo8kCEbo62D5gn46m//jfvRtT56KS5dy+j6+Rl+4Y=",
+        "lastModified": 1673752441,
+        "narHash": "sha256-/g4ImZWV05CrXRWTSJsda6ztIp7LAPxs2L6RCrbQ66U=",
         "owner": "mic92",
         "repo": "nix-index-database",
-        "rev": "0e51ff44d6bef0b6b2bbf9e34fdc029fc24820fc",
+        "rev": "391180f77505c1c8cdd45fe1a59dc89d3e40300a",
         "type": "github"
       },
       "original": {
@@ -308,11 +308,11 @@
         "nixpkgs": "nixpkgs_4"
       },
       "locked": {
-        "lastModified": 1673662873,
-        "narHash": "sha256-/YOtiDKPUXKKpIhsAds11llfC42ScGW27bbHnNZebco=",
+        "lastModified": 1673749717,
+        "narHash": "sha256-hgrw8w/AThRWfVafx3EO3/TQlGcUou4nui8X47cVhXo=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "90163bbbadce526f8b248a5fe545b06c59597108",
+        "rev": "aab6eb2dfc7a1e42d94b6f24ef13639ff8544af4",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 43bcfae..19ce7a9 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,4 +1,7 @@
 {
+  nixConfig = {
+    
+  };
   description = "My personal configuration in Nix (and some native configurations)";
   inputs = {
     nixpkgs.url = "nixpkgs/nixos-unstable";
diff --git a/nix-conf/home-manager/base/default.nix b/nix-conf/home-manager/base/default.nix
index a64a7a1..d3a0d50 100644
--- a/nix-conf/home-manager/base/default.nix
+++ b/nix-conf/home-manager/base/default.nix
@@ -1,4 +1,6 @@
-{
+{nix-index-database
+,...
+}@inputs:{
   mkModuleArgs = import ./mkModuleArgs.nix;
   modules = [
     ./alacritty.nix
@@ -8,5 +10,6 @@
     {
       config.programs.home-manager.enable = true;
     }
+    nix-index-database.hmModules.nix-index
   ];
 }
diff --git a/nix-conf/home-manager/flake.nix b/nix-conf/home-manager/flake.nix
index e461ad6..3bc3e2d 100644
--- a/nix-conf/home-manager/flake.nix
+++ b/nix-conf/home-manager/flake.nix
@@ -1,4 +1,8 @@
 {
+  nixConfig = {
+    accept-flake-config = true;
+    experimental-features = "nix-command flakes";
+  };
   description = "simple home-manager config";
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
@@ -59,7 +63,7 @@
         config = { allowUnfree = true; };
       };
       # lib = (import ../lib { inherit pkgs; lib = pkgs.lib; });
-      base = import ./base;
+      base = import ./base flake_inputs;
       inherit (base) mkModuleArgs;
 
       nerd_font_module = { config, pkgs, ... }: {
diff --git a/scripts/hm-switch.sh b/scripts/hm-switch.sh
index 2c41ad5..b99a7ac 100755
--- a/scripts/hm-switch.sh
+++ b/scripts/hm-switch.sh
@@ -2,7 +2,7 @@
 # NOTE: Untested on case of no home-manager
 set -xv
 # Where this script located
-SCRIPT_DIR=$(realpath $(dirname $0))
+SCRIPT_DIR=$(readlink -f $(dirname $0))
 echo "SCRIPT_DIR: ${SCRIPT_DIR}"
 
 HOME_MANAGER_DIR="${SCRIPT_DIR}/../nix-conf/home-manager"
diff --git a/shell.nix b/shell.nix
index 7409f9a..0995f35 100644
--- a/shell.nix
+++ b/shell.nix
@@ -3,11 +3,9 @@
 # This architecture is because we use top-level flake.nix
 (import
   (
-    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
-    fetchTarball {
-      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
-      sha256 = lock.nodes.flake-compat.locked.narHash;
-    }
+    let 
+      lock = builtins.fromJSON (builtins.readFile ./flake.lock); 
+    in (import ./c_.nix {src = ./.;}).fetchTree lock.nodes.flake-compat.locked
   )
   { src = ./.; }
 ).shellNix