update Nix tarball pins (e.g. Nixpkgs) from (n)vim

example-nixos.nix

let nixpkgs = import ./nixpkgs.nix; in
import "${nixpkgs.nixpkgs}/nixos" {
  configuration = {
    imports = [
      ./configuration.nix
    ];
  };

  system = "x86_64-linux";
}

# vim:et:sw=2:tw=78

example-shell.nix

let nixpkgs = import ./nix/nixpkgs.nix; in
{ pkgs ? nixpkgs.pkgs-unstable }:
pkgs.mkShell {
  name = "example-env";
  src = pkgs.nix-gitignore.gitignoreSource [
    "*.nix"
    ".git"
    ".gitignore"
  ] ./.;

  buildInputs = [
    pkgs.cargo-edit
    pkgs.cargo-tree
    (pkgs.nur.repos.mozilla.rustChannelOf {
      channel = "nightly";
      date = "2019-06-01";
    }).rust
  ];
}

# vim:et:sw=2:tw=78

nix-update.vim

function! NixPrefetchUrl(url)
  echom a:url
  let l:prefetch_raw = systemlist(
  \ "nix-prefetch-url --type sha256 ".shellescape(a:url)." 2>/dev/null")
  let l:prefetch = join(l:prefetch_raw, "\n")
  echom l:prefetch
  return l:prefetch
endfunction

function! NixUpdateTarball()
  let [_, l:command; _] = matchlist(getline(line(".") + 1),
  \ '\v^\s*#\s*:!\s*(.*)$')
  let l:url = trim(system(l:command))
  let [_, l:pat; _] = matchlist(getline(line(".") + 2),
  \ '\v^\s*#\s*(.*)$')
  let [_, l:sub; _] = matchlist(getline(line(".") + 3),
  \ '\v^\s*#\s*(.*)$')
  let l:fetch_url = substitute(l:url, l:pat, l:sub, '')
  let l:prefetch = NixPrefetchUrl(l:fetch_url)

  let l:save_winview = winsaveview()
  s/# .*/\="# ".trim(system("date -u '+%F %R'"))/
  +5s@\v^(\s*)url \= ".*";\n\1sha256 \= ".*";@\=submatch(1).'url = "'.l:fetch_url."\";\r".submatch(1).'sha256 = "'.l:prefetch.'";'@
  call winrestview(l:save_winview)
endfunction

function! NixPrefetchGitHub(owner, repo, rev)
  echom a:owner a:repo a:rev
  let l:prefetch_raw = systemlist(
  \ "nix-prefetch-github " . a:owner . " " . a:repo . " --rev " . a:rev)
  echom join(l:prefetch_raw, "\n")
  return json_decode(l:prefetch_raw)
endfunction

function! NixUpdateChannel()
  let l:matchline = getline(line(".") + 1)
  let [_, l:channel, l:checkowner, l:checkrepo, l:checkrev; _] =
  \ matchlist(l:matchline,
    \ '\v^\s*(.*) \= builtins\.fetchTarball \{ # (.*)/(.{-})%(#(.*))?$')
  if l:checkrev == ""
    let l:checkrev = l:channel
  endif

  let l:prefetch = NixPrefetchGitHub(l:checkowner, l:checkrepo, l:checkrev)

  let l:save_winview = winsaveview()
  s/# .*/\="# ".trim(system("date -u '+%F %R'"))/
  +2s@\v^(\s*)url \= "https://github.com/(.*)/(.*)/archive/.*\.tar\.gz";\n\1sha256 \= ".*";@\=submatch(1).'url = "https://github.com/'.submatch(2).'/'.submatch(3).'/archive/'.l:prefetch.rev.".tar.gz\";\r".submatch(1).'sha256 = "'.l:prefetch.sha256.'";'@
  call winrestview(l:save_winview)
endfunction

" vim:et:sw=2:tw=78

nixpkgs.nix

# for vim commands listed:
# :so nix-update.vim
rec {
  nixpkgs = nixpkgs;
  pkgs = instantiate nixpkgs;

  nixpkgs-stable = nixos-19_03;
  pkgs-stable = instantiate nixpkgs-stable;

  nixpkgs-unstable = nixos-unstable;
  pkgs-unstable = instantiate nixpkgs-unstable;

  instantiate = nixpkgs: import nixpkgs nixpkgsOpts;
  nixpkgsOpts = { config = nixConfig; };
  nixConfig = {
    allowUnfree = true;
    packageOverrides = pkgs: {
      nur = import nur { inherit pkgs; };
    };
  };

  # :call NixUpdateChannel()

  # 2019-06-01 18:26
  nixos-19_03 = builtins.fetchTarball { # NixOS/nixpkgs-channels#nixos-19.03
    url = "https://github.com/NixOS/nixpkgs/archive/55df3fe5f3fcb24237475671160f3114fba82d15.tar.gz";
    sha256 = "06digim3nc1xjyahr5v4k33pfmvl2aypx5653rbcx3zsjyis200q";
  };
  # 2019-06-01 18:25
  nixos-unstable = builtins.fetchTarball { # NixOS/nixpkgs-channels
    url = "https://github.com/NixOS/nixpkgs/archive/b3dd39ca0e9a8da121154e59fea86143232c0ab7.tar.gz";
    sha256 = "09n1ag253sk1jk1ci6xh64hdp031yzs4x5ja2h89wfwhpk01kmz3";
  };
  # 2019-06-01 18:24
  nur = builtins.fetchTarball { # nix-community/NUR#master
    url = "https://github.com/nix-community/NUR/archive/d1cda131b01fac4ad6dd46eb40f9f03e265ccf83.tar.gz";
    sha256 = "173c2zchk3b30qpjq3n2bdvhc66b2sg67xl7wky848zb9vh1277x";
  };

  # :call NixUpdateTarball()

  # 2019-06-01 18:56
  # :!curl -w "%{url_effective}\n" -I -L -s -S 'https://cachix.org/api/v1/install' -o /dev/null
  # \v^https://codeload.github.com/(.*)/(.*)/legacy.tar.gz/(.*)$
  # https://github.com/\1/\2/archive/\3.tar.gz
  cachix = builtins.fetchTarball {
    url = "https://github.com/NixOS/nixpkgs/archive/d45ba336b28661b16e6c8bb027bb68ba4e62c1c6.tar.gz";
    sha256 = "05knm7gsdjzy6w1xr7hskixvii95sra9vi49sx91ixym3a8rxw5g";
  };
}

# vim:et:sw=2:tw=78