mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-12-01 01:51:24 +00:00
9a8850aea9
Fixes https://github.com/dhall-lang/dhall-haskell/issues/2267 `pkgs.dhallToNix` currently fails when a Dhall package is interpolated into the input source code, like this: ```nix let pkgs = import <nixpkgs> { }; f = { buildDhallPackage }: buildDhallPackage { name = "not"; code = "λ(x : Bool) → x == False"; source = true; }; not = pkgs.dhallPackages.callPackage f {}; in pkgs.dhallToNix "${not}/source.dhall True" ``` This is because `dhallToNix` was using `builtins.toFile`, which does not permit inputs with interpolated derivations. However, `pkgs.writeText` does not have this limitation, so we can switch to using that instead.
39 lines
993 B
Nix
39 lines
993 B
Nix
/* `dhallToNix` is a utility function to convert expressions in the Dhall
|
|
configuration language to their corresponding Nix expressions.
|
|
|
|
Example:
|
|
dhallToNix "{ foo = 1, bar = True }"
|
|
=> { foo = 1; bar = true; }
|
|
dhallToNix "λ(x : Bool) → x == False"
|
|
=> x : x == false
|
|
dhallToNix "λ(x : Bool) → x == False" false
|
|
=> true
|
|
|
|
See https://hackage.haskell.org/package/dhall-nix/docs/Dhall-Nix.html for
|
|
a longer tutorial
|
|
|
|
Note that this uses "import from derivation", meaning that Nix will perform
|
|
a build during the evaluation phase if you use this `dhallToNix` utility
|
|
*/
|
|
{ stdenv, dhall-nix, writeText }:
|
|
|
|
let
|
|
dhallToNix = code :
|
|
let
|
|
file = writeText "dhall-expression" code;
|
|
|
|
drv = stdenv.mkDerivation {
|
|
name = "dhall-compiled.nix";
|
|
|
|
buildCommand = ''
|
|
dhall-to-nix <<< "${file}" > $out
|
|
'';
|
|
|
|
buildInputs = [ dhall-nix ];
|
|
};
|
|
|
|
in
|
|
import drv;
|
|
in
|
|
dhallToNix
|