feat: update .gitignore and add Nix flake support

- Simplified .gitignore by removing unnecessary macOS and C++ rules
- Added rules for build results and direnv files
- Deleted Taskfile.yml as it's no longer needed
- Introduced flake.nix and flake.lock for managing development environment using Nix flakes

Author: gen740

.gitignore

@@ -1,63 +1,13 @@
-### https://raw.github.com/github/gitignore/b0012e4930d0a8c350254a3caeedf7441ea286a3/Global/macOS.gitignore
-build*
-cmake_build
-.build
-_build
+# Build folder
+result
+build
 
 # General
 .DS_Store
-.AppleDouble
-.LSOverride
 
-# Icon must end with two \r
-Icon
-
-
-# Thumbnails
-._*
+# Direnv
+.envrc
+.direnv
 
-# Files that might appear in the root of a volume
-.DocumentRevisions-V100
-.fseventsd
-.Spotlight-V100
-.TemporaryItems
-.Trashes
-.VolumeIcon.icns
-.com.apple.timemachine.donotpresent
+# Task file
 .task
-
-### https://raw.github.com/github/gitignore/b0012e4930d0a8c350254a3caeedf7441ea286a3/C++.gitignore
-
-# Prerequisites
-*.d
-
-# Compiled Object files
-*.slo
-*.lo
-*.o
-*.obj
-
-# Precompiled Headers
-*.gch
-*.pch
-
-# Compiled Dynamic libraries
-*.so
-*.dylib
-*.dll
-
-# Fortran module files
-*.mod
-*.smod
-
-# Compiled Static libraries
-*.lai
-*.la
-*.a
-*.lib
-
-# Executables
-*.exe
-*.out
-*.app
-.envrc

Taskfile.yml

@@ -0,0 +1,56 @@
+{
+  description = "Flake shell";
+  # inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  inputs.nixpkgs.url = "github:gen740/nixpkgs/cxx-import-std";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs =
+    { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system: with nixpkgs.legacyPackages.${system}; {
+        devShells.default = mkShellNoCC {
+          packages = [
+            llvmPackages_19.clang-tools
+            (llvmPackages_19.libcxxClang.overrideAttrs (oldAttrs: {
+              postFixup =
+                oldAttrs.postFixup
+                + ''
+                  ln -sf  ${oldAttrs.passthru.libcxx}/lib/libc++.modules.json $out/resource-root/libc++.modules.json
+                  ln -sf  ${oldAttrs.passthru.libcxx}/share $out
+                '';
+            }))
+            (cmake.overrideAttrs (oldAttrs: {
+              version = "3.30.2";
+              src = oldAttrs.src.overrideAttrs { outputHash = null; };
+            }))
+            ninja
+          ];
+        };
+
+        defaultPackage = stdenv.mkDerivation {
+          name = "import_std_example";
+          src = ./.;
+          nativeBuildInputs = [
+            llvmPackages_19.clang-tools
+            (llvmPackages_19.libcxxClang.overrideAttrs (oldAttrs: {
+              postFixup =
+                oldAttrs.postFixup
+                + ''
+                  ln -sf  ${oldAttrs.passthru.libcxx}/lib/libc++.modules.json $out/resource-root/libc++.modules.json
+                  ln -sf  ${oldAttrs.passthru.libcxx}/share $out
+                '';
+            }))
+            (cmake.overrideAttrs (oldAttrs: {
+              version = "3.30.2";
+              src = oldAttrs.src.overrideAttrs { outputHash = null; };
+            }))
+            ninja
+          ];
+          installPhase = ''
+            mkdir -p $out/bin
+            cp main $out/bin
+          '';
+        };
+      }
+    );
+}