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.
38 lines
993 B
Nix
38 lines
993 B
Nix
/* `dhallToNix` is a utility function to convert expressions in the Dhall
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configuration language to their corresponding Nix expressions.
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Example:
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dhallToNix "{ foo = 1, bar = True }"
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=> { foo = 1; bar = true; }
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dhallToNix "λ(x : Bool) → x == False"
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=> x : x == false
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dhallToNix "λ(x : Bool) → x == False" false
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=> true
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See https://hackage.haskell.org/package/dhall-nix/docs/Dhall-Nix.html for
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a longer tutorial
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Note that this uses "import from derivation", meaning that Nix will perform
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a build during the evaluation phase if you use this `dhallToNix` utility
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*/
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{ stdenv, dhall-nix, writeText }:
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let
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dhallToNix = code :
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let
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file = writeText "dhall-expression" code;
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drv = stdenv.mkDerivation {
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name = "dhall-compiled.nix";
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buildCommand = ''
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dhall-to-nix <<< "${file}" > $out
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'';
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buildInputs = [ dhall-nix ];
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};
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in
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import drv;
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in
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dhallToNix
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