use flake .
#use flake .#default
NIX_ENFORCE_PURITY=1
NixDirEnvVersion="2.2.1"
if ! has nix_direnv_version || ! nix_direnv_version ${NixDirEnvVersion}; then
# - https://github.com/nix-community/nix-direnv
# source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/${NixDirEnvVersion}/direnvrc" "sha256-0000000000000000000000000000000000000000000="
  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/${NixDirEnvVersion}/direnvrc" "sha256-zelF0vLbEl5uaqrfIzbgNzJWGmLzCmYAkInj/LNxvKs="
fi
watch_file flake.lock
watch_file flake.nix
if [ -f .envrc-local ]; then
  source_env_if_exists .envrc-local || source .envrc-local
fi
PATH_add result/bin
#nix flake update && nix flake check --show-trace && nix flake show