init cpp repo

flake.nix

@@ -0,0 +1,63 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    nixpkgs-gcc15.url = "github:NixOS/nixpkgs/?ref=pull/401948/head";
+    nixpkgs-cmake.url = "github:NixOS/nixpkgs/?ref=pull/394444/head";
+  };
+  outputs =
+    {
+      nixpkgs-cmake,
+      nixpkgs-gcc15,
+      nixpkgs,
+      flake-utils,
+      ...
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        inherit
+          (import nixpkgs-cmake {
+            inherit system;
+            config = {
+              cudaSupport = true;
+            };
+          })
+          cmake
+          ;
+        inherit
+          (import nixpkgs-gcc15 {
+            inherit system;
+            config = {
+              cudaSupport = true;
+            };
+          })
+          gcc15
+          gcc15Stdenv
+          ;
+        pkgs = import nixpkgs {
+          inherit system;
+          config = {
+            cudaSupport = true;
+          };
+        };
+      in
+      {
+        devShells.default =
+          pkgs.mkShell.override
+            {
+              stdenv = pkgs.llvmPackages_20.libcxxStdenv;
+              # stdenv = gcc15Stdenv;
+            }
+            {
+              packages = with pkgs; [
+                llvmPackages_20.clang-tools
+                gnumake
+                llvmPackages_20.clang
+                bear
+                # cmake
+                # gcc15
+              ];
+            };
+      }
+    );
+}