add nix flake

Author: adamjhf

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -1,14 +1,2 @@
-# Generated by Cargo
-# will have compiled files and executables
-/target/
-
-# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
-# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
-Cargo.lock
-
-# These are backup files generated by rustfmt
-**/*.rs.bk
-
-**/.idea/*
-
-**/main.rs
+target/**
+.direnv/**

flake.lock

@@ -0,0 +1,50 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    fenix.url = "github:nix-community/fenix";
+    fenix.inputs.nixpkgs.follows = "nixpkgs";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      nixpkgs,
+      fenix,
+      flake-utils,
+      ...
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+        };
+
+        # https://github.com/nix-community/fenix/issues/178
+        cargo = fenix.packages.${system}.stable.cargo.overrideAttrs (old: {
+          postBuild = pkgs.lib.optionalString pkgs.stdenv.isDarwin ''
+            cargo="./cargo/bin/cargo"
+            install_name_tool \
+              -change "/usr/lib/libcurl.4.dylib" "${pkgs.curl.out}/lib/libcurl.4.dylib" \
+              "$cargo"
+          '';
+        });
+        rustToolchain =
+          with fenix.packages.${system};
+          combine [
+            cargo
+            stable.rustc
+            stable.clippy
+            stable.rustfmt
+          ];
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            rustToolchain
+            rust-analyzer
+          ];
+        };
+      }
+    );
+}