Build Helpers in Nix

# Build helpers {#part-builders} A build helper is a function that produces derivations. :::{.warning} This is not to be confused with the [`builder` argument of the Nix `derivation` primitive](https://nixos.org/manual/nix/unstable/language/derivations.html), which refers to the executable that produces the build result, or [remote builder](https://nixos.org/manual/nix/stable/advanced-topics/distributed-builds.html), which refers to a remote machine that could run such an executable. ::: Such a function is usually designed to abstract over a typical workflow for a given programming language or framework. This allows declaring a build recipe by setting a limited number of options relevant to the particular use case instead of using the `derivation` function directly. [`stdenv.mkDerivation`](#part-stdenv) is the most widely used build helper, and serves as a basis for many others. In addition, it offers various options to customize parts of the builds. There is no uniform interface for build helpers. [Trivial build helpers](#chap-trivial-builders) and [fetchers](#chap-pkgs-fetchers) have various input types for convenience. [Language- or framework-specific build helpers](#chap-language-support) usually follow the style of `stdenv.mkDerivation`, which accepts an attribute set or a fixed-point function taking an attribute set. ```{=include=} chapters build-helpers/fixed-point-arguments.chapter.md build-helpers/fetchers.chapter.md build-helpers/trivial-build-helpers.chapter.md build-helpers/testers.chapter.md build-helpers/dev-shell-tools.chapter.md build-helpers/special.md build-helpers/images.md hooks/index.md languages-frameworks/index.md packages/index.md ```

This section introduces build helpers in Nix, which are functions that produce derivations and abstract over typical workflows for specific programming languages or frameworks. The most widely used build helper is `stdenv.mkDerivation`, which serves as a basis for many others. Build helpers do not have a uniform interface and can accept various input types. The following chapters delve into trivial build helpers, fetchers, language-specific build helpers, testers, dev shell tools, special build helpers, images, hooks, language/framework support, and packages.