From (https://github.com/bbarker/LearningAgda): NixOS support file for Agda-Pkg

agda_requirements.txt

standard-library==v1.2

deps.nix

with import <nixpkgs> {};
let
  thisAgda = pkgs.haskellPackages.ghcWithPackages ( p: [p.Agda p.ieee754] );
in
agda.mkDerivation(self:  {
  name = "commonAgdaDeps";
  dontUnpack = true;
  myAgda = thisAgda;
  buildDepends = [
    thisAgda
    # Using agda-pkg instead for deps for now:
    # pkgs.AgdaStdlib (pkgs.haskellPackages.ghcWithPackages ( p: [p.ieee]) )
    # pkgs.agdaPrelude (pkgs.haskellPackages.ghcWithPackages ( p: [p.ieee]) )
  ];
  src = null;
})

emacs.nix

{ pkgs ? import <nixpkgs> {} }: 
let
  myEmacs = pkgs.emacs26-nox; 
  emacsWithPackages = (pkgs.emacsPackagesGen myEmacs).emacsWithPackages;
  deps = (import ./deps.nix);
in
  emacsWithPackages (epkgs: (with epkgs.melpaStablePackages; [ 
    magit          # ; Integrate git <C-x g>
    zerodark-theme # ; Nicolas' theme
  ]) ++ (with epkgs.melpaPackages; [ 
    # undo-tree      # ; <C-x u> to show the undo tree
    # zoom-frm       # ; increase/decrease font size for all buffers %lt;C-x C-+>
  ]) ++ (with epkgs.elpaPackages; [ 
    auctex         # ; LaTeX mode
    beacon         # ; highlight my cursor when scrolling
    nameless       # ; hide current package name everywhere in elisp code
  ]) ++ [
    deps.myAgda # This is where agda-mode is located
    # pkgs.notmuch   # From main packages set 
  ])

hello-world.agda

module hello-world where

open import IO

main = run (putStrLn "Hello, World!")

shell.nix

with import <nixpkgs> {};
let
  deps = (import ./deps.nix);
  myEmacs = (import ./emacs.nix { inherit pkgs; });
  
in
agda.mkDerivation(self:  {
  name = "agdaShellEnv";
  dontUnpack = true;
  buildDepends = deps.buildDepends;
  buildInputs = deps.buildInputs ++ [
    myEmacs

    # these packages are required for virtualenv and pip to work:
    #
    mypy
    python38Full
    python38Packages.virtualenv
  ];
  # libPath = deps.libPath;
  src = null;
  shellHook = ''

    # set SOURCE_DATE_EPOCH so that we can use python wheels
    SOURCE_DATE_EPOCH=$(date +%s)
    export LANG=en_US.UTF-8

    activate_python_env () {
      source venv/bin/activate
      export PATH=$PWD/venv/bin:$PATH
      export PYTHONPATH=$PWD:$PYTHONPATH
    }
    
    if [ ! -d "venv" ]; then
      # initialize python environment
      virtualenv venv
      activate_python_env
      pip install agda-pkg
    else
      activate_python_env
    fi

    export AGDA_PROJ_DIR=$PWD
    export AGDA_DIR=$AGDA_PROJ_DIR/.agda
    if [ ! -d "$AGDA_DIR" ]; then
      mkdir -p "$AGDA_DIR"
      apkg init
      apkg upgrade
      apkg install -r agda_requirements.txt
    fi


    if [ ! -f "$AGDA_PROJ_DIR/.emacs" ]; then
      export ORIG_HOME=$HOME
      export HOME=$AGDA_PROJ_DIR

      echo '(load (expand-file-name "~/.emacs") "" nil t)' > $AGDA_PROJ_DIR/.emacs
      agda-mode setup
      export EMACS_USER_FILE="$AGDA_PROJ_DIR/.emacs_user_config"
      if [ -f "$EMACS_USER_FILE" ]; then
        cat "$EMACS_USER_FILE" >> $AGDA_PROJ_DIR/.emacs
      fi
      export HOME=$ORIG_HOME
      unset ORIG_HOME
      rmdir .emacs.d
      unset EMACS_USER_FILE
    fi
    
    mymacs () {
      emacs -Q --load $AGDA_PROJ_DIR/.emacs $@
    }
  '';
})

Hi, I recently found a few issues in deps.nix and shell.nix: I put in fixes at https://gist.github.com/bbarker/c0c7f014a9ee677f83b03a3fe6c93bf9