migrate to nix flake (#126)

.license-header

@@ -0,0 +1,5 @@
+Copyright (c) 2022 Espresso Systems (espressosys.com)
+This file is part of the Jellyfish library.
+
+You should have received a copy of the MIT License
+along with the Jellyfish library. If not, see <https://mit-license.org/>.

Cargo.toml

@@ -1,8 +1,8 @@
 [workspace]
 members = [
   "plonk",
-  "relation",
   "primitives",
+  "relation",
   "utilities",
   "utilities_derive",
 ]

README.md

@@ -1,4 +1,5 @@
 # Jellyfish cryptographic library
+
 ![example workflow](https://github.com/EspressoSystems/jellyfish/actions/workflows/build.yml/badge.svg)
 ![Crates.io (version)](https://img.shields.io/crates/dv/jf-plonk/0.1.0)
 ![GitHub](https://img.shields.io/github/license/EspressoSystems/jellyfish)
@@ -8,7 +9,7 @@
 **DISCLAIMER:** This software is provided "as is" and its security has not been externally audited. Use at your own risk.
 
 ## Chatroom
- 
+
 For general discussions on Jellyfish PLONK, please join our [Discord channel](https://discord.gg/GJa4gznGfU).
 
 ## Development environment setup
@@ -100,15 +101,12 @@ To format your code run
 
 ### Updating non-cargo dependencies
 
-- To update the [nix packages](https://github.com/NixOS/nixpkgs) run `./nix/update-nix`.
-- To update the [rust overlay](https://github.com/oxalica/rust-overlay) run
-  `./nix/update-rust-overlay`.
-
-To use the updates enter a new `nix-shell`.
+Run `nix flake update` if you would like to pin other version edit `flake.nix`
+beforehand. Commit the lock file when happy.
 
-### Testing the nix-shell dev environment on other platforms
+To update only a single input specify it as argument, for example
 
-Refer to the [nix/vagrant](./nix/vagrant/) directory.
+    nix flake update github:oxalica/rust-overlay
 
 ### Benchmarks
 

flake.nix

@@ -0,0 +1,98 @@
+# Copyright (c) 2022 Espresso Systems (espressosys.com)
+# This file is part of the Jellyfish library.
+
+# You should have received a copy of the MIT License
+# along with the Jellyfish library. If not, see <https://mit-license.org/>.
+
+{
+  description = "Jellyfish dev env";
+
+  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  inputs.flake-utils.url = "github:numtide/flake-utils"; # for dedup
+
+  # allow shell.nix alongside flake.nix
+  inputs.flake-compat.url = "github:edolstra/flake-compat";
+  inputs.flake-compat.flake = false;
+
+  inputs.rust-overlay.url = "github:oxalica/rust-overlay";
+  inputs.pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
+
+  outputs = { self, nixpkgs, flake-utils, flake-compat, rust-overlay, pre-commit-hooks, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs { inherit system overlays; };
+        nightlyToolchain = pkgs.rust-bin.selectLatestNightlyWith
+          (toolchain: toolchain.minimal.override { extensions = [ "rustfmt" ]; });
+
+        stableToolchain = pkgs.rust-bin.stable.latest.minimal.override {
+          extensions = [ "clippy" "llvm-tools-preview" "rust-src" ];
+        };
+      in with pkgs;
+      {
+        check = {
+          pre-commit-check = pre-commit-hooks.lib.${system}.run {
+            src = ./.;
+            hooks = {
+              check-format = {
+                enable = true;
+                files = "\\.rs$";
+                entry = "cargo fmt -- --check";
+              };
+              doctest = {
+                enable = true;
+                entry = "cargo test --doc";
+                files = "\\.rs$";
+                pass_filenames = false;
+              };
+              cargo-clippy = {
+                enable = true;
+                description = "Lint Rust code.";
+                entry = "cargo-clippy --workspace -- -D warnings";
+                files = "\\.rs$";
+                pass_filenames = false;
+              };
+              cargo-sort = {
+                enable = true;
+                description = "Ensure Cargo.toml are sorted";
+                entry = "cargo sort -w";
+                pass_filenames = false;
+              };
+              license-header-c-style = {
+                enable = true;
+                description =
+                  "Ensure files with c-style comments have license header";
+                entry = ''
+                  insert_license --license-filepath .license-header  --comment-style "//"'';
+                types_or = [ "rust" ];
+                pass_filenames = true;
+              };
+            };
+          };
+        };
+        devShell = mkShell {
+          buildInputs = [
+            argbash
+            openssl
+            pkgconfig
+            git
+
+            stableToolchain
+            nightlyToolchain
+            cargo-sort
+
+          ] ++ lib.optionals stdenv.isDarwin [ darwin.apple_sdk.frameworks.Security ];
+
+          shellHook = ''
+            export RUST_BACKTRACE=full
+            export PATH="$PATH:$(pwd)/target/debug:$(pwd)/target/release"
+
+            # Ensure `cargo fmt` uses `rustfmt` from nightly.
+            export RUSTFMT="${nightlyToolchain}/bin/rustfmt"
+          ''
+          # install pre-commit hooks
+          + self.check.${system}.pre-commit-check.shellHook;
+        };
+      }
+    );
+}