diff options
Diffstat (limited to 'nixpkgs/pkgs/build-support/dhall/to-nix.nix')
-rw-r--r-- | nixpkgs/pkgs/build-support/dhall/to-nix.nix | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/build-support/dhall/to-nix.nix b/nixpkgs/pkgs/build-support/dhall/to-nix.nix new file mode 100644 index 000000000000..96cc16e16f36 --- /dev/null +++ b/nixpkgs/pkgs/build-support/dhall/to-nix.nix @@ -0,0 +1,38 @@ +/* `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 |