2018-08-31 17:23:04 +02:00
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# `dhall-nix 1.1.6`
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2017-01-22 04:13:50 +01:00
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This `dhall-nix` package provides a Dhall to Nix compiler. You can use this
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compiler to program Nix using the Dhall language. This package targets people
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who wish Nix had a type system.
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## Quick start
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If you have Nix installed then you can build and run this package using:
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```bash
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$ nix-build -A dhall-nix release.nix
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$ result/bin/dhall-to-nix <<< "λ(x : Bool) → x == False"
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x: x == false
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$ result/bin/dhall-to-nix <<< "{ foo = 1, bar = True }"
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{ bar = true; foo = 1; }
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$ result/bin/dhall-to-nix <<< "< Left = 2 | Right : Natural >"
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{ Left, Right }: Left 2
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```
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However, this package is also designed to be used directly from Nix. You can
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use the following `dhallToNix` utility to translate Dhall source code to the
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corresponding Nix expression directly within Nix:
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```nix
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dhallToNix = code :
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let
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file = builtins.toFile "dhall-expr" code;
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drv = pkgs.stdenv.mkDerivation {
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name = "dhall-expr-as-nix";
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buildCommand = ''
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dhall-to-nix <<< "${file}" > $out
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'';
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buildInputs = [ pkgs.haskellPackages.dhall-nix ];
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};
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in
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import "${drv}";
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```
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2017-03-01 17:46:20 +01:00
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The above `dhallToNix` utility is now in `nixpkgs` so you can use `pkgs.dhallToNix`
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to transform Dhall expressions to Nix expressions
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2017-01-22 04:13:50 +01:00
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## Development status
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[](https://travis-ci.org/Gabriel439/Haskell-Dhall-Nix-Library)
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I don't expect this library to change unless:
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* ... the Dhall language changes, which is possible but not very likely
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* ... there are bugs, but the test suite in [release.nix](./release.nix) should
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protect against this
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## License (BSD 3-clause)
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Copyright (c) 2017 Gabriel Gonzalez
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All rights reserved.
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Redistribution and use in source and binary forms, with or without modification,
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are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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* Neither the name of Gabriel Gonzalez nor the names of other contributors
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may be used to endorse or promote products derived from this software
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without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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