Merge pull request #41 from paulrbr-fl/dhall-version-upgrade

dhall(upgrade): upgrade code to be compatible with dhall 1.21.0

.travis.yml

@@ -4,9 +4,8 @@ language: nix
 sudo: false
 
 install:
-  - nix-env -i python2.7-ansible
-  - nix-env -i python2.7-ansible-lint
-  - nix-env -if ./dhall-1.18.nix
+  - nix-env -i python2.7-ansible python2.7-ansible-lint
+  - nix-env -if ./dhall-1.21.0.nix
 
   # Check ansible version
   - ansible --version

dhall-1.21.0.nix

@@ -0,0 +1,22 @@
+{ pkgs ? import <nixpkgs> {} }: with pkgs;
+
+let
+  mkVersion =
+    version: sha256:
+      stdenv.mkDerivation {
+        name = "dhall-${version}";
+        inherit version;
+        src = fetchurl {
+          url = "https://github.com/dhall-lang/dhall-haskell/releases/download/${version}/dhall-${version}-x86_64-linux.tar.bz2";
+          inherit sha256;
+        };
+        unpackPhase = ''
+          tar -xjf $src
+        '';
+        installPhase = ''
+          mkdir -p $out/bin
+          mv bin/dhall $out/bin/
+        '';
+      };
+in
+  mkVersion "1.21.0" "0x7q6v1y62fq6724kx1hcfp1fcqv3lbv33ji6jzfd5y316a31r77"

dhall/addon/Postgresql.dhall

@@ -1,3 +1,3 @@
-    let addon = constructors ./Addon.dhall
+let addon = ./Addon.dhall
 
 in  addon.Postgresql { name = "pg", env_prefix = "POSTGRESQL_ADDON" }