chore: add standard devenv.nix #5

.devenv.flake.nix

+{
+  inputs = {
+    pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
+    pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    devenv.url = "github:cachix/devenv?dir=src/modules";
+  } // (if builtins.pathExists ./.devenv/flake.json 
+       then builtins.fromJSON (builtins.readFile ./.devenv/flake.json)
+       else {});
+
+  outputs = { nixpkgs, ... }@inputs:
+    let
+      devenv = if builtins.pathExists ./.devenv/devenv.json
+        then builtins.fromJSON (builtins.readFile ./.devenv/devenv.json)
+        else {};
+      getOverlays = inputName: inputAttrs:
+        map (overlay: let
+            input = inputs.${inputName} or (throw "No such input `${inputName}` while trying to configure overlays.");
+          in input.overlays.${overlay} or (throw "Input `${inputName}` has no overlay called `${overlay}`. Supported overlays: ${nixpkgs.lib.concatStringsSep ", " (builtins.attrNames input.overlays)}"))
+          inputAttrs.overlays or [];
+      overlays = nixpkgs.lib.flatten (nixpkgs.lib.mapAttrsToList getOverlays (devenv.inputs or {}));
+      pkgs = import nixpkgs {
+        system = "x86_64-linux";
+        config = {
+          allowUnfree = devenv.allowUnfree or false;
+          permittedInsecurePackages = devenv.permittedInsecurePackages or [];
+        };
+        inherit overlays;
+      };
+      lib = pkgs.lib;
+      importModule = path:
+        if lib.hasPrefix "./" path
+        then ./. + (builtins.substring 1 255 path) + "/devenv.nix"
+        else if lib.hasPrefix "../" path 
+            then throw "devenv: ../ is not supported for imports"
+            else let
+              paths = lib.splitString "/" path;
+              name = builtins.head paths;
+              input = inputs.${name} or (throw "Unknown input ${name}");
+              subpath = "/${lib.concatStringsSep "/" (builtins.tail paths)}";
+              devenvpath = "${input}" + subpath + "/devenv.nix";
+              in if builtins.pathExists devenvpath
+                then devenvpath
+                else throw (devenvpath + " file does not exist for input ${name}.");
+      project = pkgs.lib.evalModules {
+        specialArgs = inputs // { inherit inputs pkgs; };
+        modules = [
+          (inputs.devenv.modules + /top-level.nix)
+          { devenv.cliVersion = "0.6.3"; }
+        ] ++ (map importModule (devenv.imports or [])) ++ [
+          ./devenv.nix
+          (devenv.devenv or {})
+          (if builtins.pathExists ./devenv.local.nix then ./devenv.local.nix else {})
+        ];
+      };
+      config = project.config;
+
+      options = pkgs.nixosOptionsDoc {
+        options = builtins.removeAttrs project.options [ "_module" ];
+        # Unpack Nix types, e.g. literalExpression, mDoc.
+        transformOptions =
+          let isDocType = v: builtins.elem v [ "literalDocBook" "literalExpression" "literalMD" "mdDoc" ];
+          in lib.attrsets.mapAttrs (_: v:
+            if v ? _type && isDocType v._type then
+              v.text
+            else if v ? _type && v._type == "derivation" then
+              v.name
+            else
+              v
+          );
+      };
+    in {
+      packages."x86_64-linux" = {
+        optionsJSON = options.optionsJSON;
+        inherit (config) info procfileScript procfileEnv procfile;
+        ci = config.ciDerivation;
+      };
+      devenv.containers = config.containers;
+      devShell."x86_64-linux" = config.shell;
+    };
+}

.devenv/devenv.json

+{"inputs": {"nixpkgs": {"url": "github:nixos/nixpkgs/nixos-23.05"}, "version": {"url": "git+https://gitlab.schukai.com/oss/utilities/version.git", "flake": true}}, "allowUnfree": false}
\ No newline at end of file

.devenv/flake.json

+{"nixpkgs": {"url": "github:nixos/nixpkgs/nixos-23.05"}, "version": {"url": "git+https://gitlab.schukai.com/oss/utilities/version.git", "flake": true}}
\ No newline at end of file

.devenv/gc/shell

+shell-2-link
\ No newline at end of file

.devenv/gc/shell-2-link

+/nix/store/1ppns0fipd84msivyw8ypd4804zn8jli-devenv-shell-env
\ No newline at end of file

.devenv/profile

+/nix/store/ishxkjwm6m1nq2dzailw41xw5rczf6hi-devenv-profile
\ No newline at end of file

.devenv/state/go/pkg/mod/cache/download/github.com/agnivade/levenshtein/@v/list

+v1.1.1

.devenv/state/go/pkg/mod/cache/download/github.com/agnivade/levenshtein/@v/v1.1.1.mod

+module github.com/agnivade/levenshtein
+
+go 1.13
+
+require (
+	github.com/arbovm/levenshtein v0.0.0-20160628152529-48b4e1c0c4d0
+	github.com/dgryski/trifles v0.0.0-20200323201526-dd97f9abfb48
+)

.devenv/state/go/pkg/mod/cache/download/github.com/arbovm/levenshtein/@v/list

+v0.0.0-20160628152529-48b4e1c0c4d0

.devenv/state/go/pkg/mod/cache/download/github.com/arbovm/levenshtein/@v/v0.0.0-20160628152529-48b4e1c0c4d0.mod

+module github.com/arbovm/levenshtein

.devenv/state/go/pkg/mod/cache/download/github.com/davecgh/go-spew/@v/list

+v1.1.0
+v1.1.1

.devenv/state/go/pkg/mod/cache/download/github.com/davecgh/go-spew/@v/v1.1.0.mod

+module github.com/davecgh/go-spew

.devenv/state/go/pkg/mod/cache/download/github.com/davecgh/go-spew/@v/v1.1.1.info

+{"Version":"v1.1.1","Time":"2018-02-21T23:26:28Z"}
\ No newline at end of file

.devenv/state/go/pkg/mod/cache/download/github.com/davecgh/go-spew/@v/v1.1.1.mod

+module github.com/davecgh/go-spew

.devenv/state/go/pkg/mod/cache/download/github.com/davecgh/go-spew/@v/v1.1.1.ziphash

+h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
\ No newline at end of file

.devenv/state/go/pkg/mod/cache/download/github.com/dgryski/trifles/@v/list

+v0.0.0-20200323201526-dd97f9abfb48

.devenv/state/go/pkg/mod/cache/download/github.com/dgryski/trifles/@v/v0.0.0-20200323201526-dd97f9abfb48.mod

+module github.com/dgryski/trifles