Add nix shell

shell.nix

@@ -0,0 +1,48 @@
+{ pkgs ? import (fetchTarball https://github.com/NixOS/nixpkgs/archive/23.05.tar.gz) {} }:
+
+let
+  pythonPkgs = pkgs.python3Packages;
+  boostPython = pkgs.boost.override { python = pythonPkgs.python; enablePython = true; };
+  vscode = pkgs.vscode-with-extensions.override {
+    vscodeExtensions = with pkgs.vscode-extensions; [
+      bbenoist.nix
+      ms-vscode.cpptools
+      ms-vscode.cmake-tools
+      twxs.cmake
+      usernamehw.errorlens
+      llvm-vs-code-extensions.vscode-clangd
+    ] ++ pkgs.vscode-utils.extensionsFromVscodeMarketplace [
+      {
+        name = "VerilogHDL";
+        publisher = "mshr-h";
+        version = "1.11.4";
+        sha256 = "sha256-4JY0eaN2IkwHv8u8X6ejDXk6vT1qB4vJjWdIy8b/jj4=";
+      }
+    ];
+  };
+in pkgs.mkShell {
+  buildInputs = with pkgs; [
+    cmake
+    eigen
+    boostPython
+    pythonPkgs.python
+    pythonPkgs.apycula
+    libsForQt5.qt5.qtbase
+    llvmPackages.openmp
+    icestorm
+    trellis
+    mold
+    yosys
+    clang
+    valgrind
+    cling
+    gdb
+    vscode
+  ];
+
+  shellHook = ''
+    export TRELLIS_INSTALL_PREFIX=${pkgs.trellis}
+    export ICESTORM_INSTALL_PREFIX=${pkgs.icestorm}
+    export QT_QPA_PLATFORM_PLUGIN_PATH="${pkgs.libsForQt5.qt5.qtbase.bin}/lib/qt-${pkgs.libsForQt5.qt5.qtbase.version}/plugins";
+  '';
+}