Hare

Building Hare programs with hareHook

The hareHook package sets up the environment for building Hare programs by doing the following:

1. Setting the HARECACHE, HAREPATH and NIX_HAREFLAGS environment variables;
2. Propagating harec, qbe and two wrapper scripts for the hare binary.

It is not a function as is the case for some other languages --- e. g., Go or Rust ---, but a package to be added to nativeBuildInputs.

Attributes of hareHook

The following attributes are accepted by hareHook:

1. hareBuildType: Either release (default) or debug. It controls if the -R flag is added to NIX_HAREFLAGS.

Example for `hareHook

{
  hareHook,
  lib,
  stdenv,
}:
stdenv.mkDerivation {
  pname = "<name>";
  version = "<version>";
  src = "<src>";

  nativeBuildInputs = [ hareHook ];

  meta = {
    description = "<description>";
    inherit (hareHook) badPlatforms platforms;
  };
}
```

## <a id="hareHook-cross-compilation"></a> Cross Compilation
`hareHook` should handle cross compilation out of the box. This is the main
purpose of `NIX_HAREFLAGS`: In it, the `-a` flag is passed with the architecture
of the `hostPlatform`.

However, manual intervention may be needed when a binary compiled by the build
process must be run for the build to complete --- *e. g.*, when using Hare's
`hare` module for code generation.

In those cases, `hareHook` provides the `hare-native` script, which is a wrapper
around the hare binary for using the native (`buildPlatform`) toolchain.

nixos.org/manual/nixpkgs/stable/languages-frameworks/hare.html