Nix-writers

Nix-writers are a way to write other programming languages inline in nix-code. They are like writeScript/writeScriptBin but for other languages.

Every writer has a ...Bin variant which can be used inside environment.systemPackages. Most of the writers take an attrributeset where one can add libraries.

Languages

bash

This is basically writeScript but with the shebang to bash already included.

pkgs.writers.writeBash "hello_world" ''
  echo 'hello world!'
''

dash

pkgs.writers.writeDash "hello_world" ''
  echo 'hello world!'
''

Haskell

writeHaskell "missiles" {
  libraries = [ pkgs.haskellPackages.acme-missiles ];
} ''
  import Acme.Missiles

  main = launchMissiles
''

JavaScript

writeJS "example" {
  libraries = [ pkgs.nodePackages.uglify-js ];
} ''
  var UglifyJS = require("uglify-js");
  var code = "function add(first, second) { return first + second; }";
  var result = UglifyJS.minify(code);
  console.log(result.code);
''

Perl

writePerl "example" {
  libraries = [ pkgs.perlPackages.boolean ];
} ''
  use boolean;
  print "Howdy!\n" if true;
''

Python2

writePython2 "test_python2" {
  deps = [ pkgs.python2Packages.enum ];
} ''
  from enum import Enum

  class Test(Enum):
      a = "success"

  print Test.a
''

Python3

writePython3 "test_python3" {
  libraries = [ pkgs.python3Packages.pyyaml ];
} ''
  import yaml

  y = yaml.load("""
    - test: success
  """)
  print(y[0]['test'])
''

To disable errors use 'flakeIgnore' like this:

writePython3 "test_python3" {
  libraries = [ pkgs.python3Packages.pyyaml ];
  flakeIgnore = [ "E265" "E225" ];
} ''
  import yaml

  y = yaml.load("""
    - test: success
  """)
  print(y[0]['test'])
''