Reformat libosmium example and build it on CI

examples/cpp-libosmium/default.nix

@@ -0,0 +1,37 @@
+let
+  sources = import ./nix/sources.nix;
+  pkgs = import sources.nixpkgs {
+    overlays = [
+      (_: _: { inherit sources; })
+      (import ./overlay.nix)
+    ];
+  };
+in
+  with pkgs;
+
+  stdenv.mkDerivation {
+    name = "nix-cpp-demo";
+    nativeBuildInputs = [ cmake pkgconfig ];
+    src = pkgs.lib.cleanSource ./.;
+
+    # tell Cmake location of all headers
+    cmakeFlags = [
+      "-DEXTERNAL_INCLUDE_DIRECTORIES=${stdenv.lib.strings.makeSearchPathOutput "dev" "include" libosmium.buildInputs}"
+    ];
+
+    buildInputs = stdenv.lib.lists.concatLists [
+      # We want to check if dependencies exist using find_package
+      [
+        libosmium.buildInputs
+      ]
+      # dependencies
+      [
+        libosmium
+      ]
+    ];
+
+    installPhase = ''
+      mkdir -p $out/bin
+      cp bin/hello-world $out/bin
+    '';
+  }

examples/cpp-libosmium/nix/sources.nix

@@ -19,7 +19,7 @@ let
       pkgs.fetchzip { inherit (spec) url sha256; };
 
   fetch_git = spec:
-      builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
+    builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
 
   fetch_builtin-tarball = spec:
     builtins.trace
@@ -125,12 +125,14 @@ let
   # The "config" used by the fetchers
   mkConfig =
     { sourcesFile ? ./sources.json
+    , sources ? builtins.fromJSON (builtins.readFile sourcesFile)
+    , pkgs ? mkPkgs sources
     }: rec {
       # The sources, i.e. the attribute set of spec name to spec
-      sources = builtins.fromJSON (builtins.readFile sourcesFile);
+      inherit sources;
+
       # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
-      pkgs = mkPkgs sources;
+      inherit pkgs;
     };
 in
-mkSources (mkConfig {}) //
-  { __functor = _: settings: mkSources (mkConfig settings); }
+mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }

examples/cpp-libosmium/overlay.nix

@@ -1,3 +1,3 @@
 self: super: {
   libosmium = self.callPackage ./overlay/libosmium.nix {};
-}
+}

examples/cpp-libosmium/overlay/libosmium.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, cmake, protozero, expat, zlib, bzip2, boost, sources ? import ../nix/sources.nix  }:
+{ stdenv, cmake, protozero, expat, zlib, bzip2, boost, sources }:
 
 stdenv.mkDerivation rec {
   name = "libosmium";
@@ -13,10 +13,10 @@ stdenv.mkDerivation rec {
     "-DBUILD_TESTING=OFF"
   ];
   buildInputs = [
-    protozero 
+    protozero
     expat
-    zlib 
-    bzip2  
+    zlib
+    bzip2
     boost
   ];
-}
+}

examples/cpp/default.nix

@@ -1,37 +0,0 @@
-{ 
-  # import the sources
-  sources ? import ./nix/sources.nix
-}:     
-let 
-  pkgs = import sources.nixpkgs { 
-     overlays = [ (import ./overlay.nix) ];
-  };
-in
-with pkgs;
-
-stdenv.mkDerivation {
-    name = "nix-cpp-demo";
-    nativeBuildInputs = [ cmake pkgconfig];
-    src = ./.;
-
-    # tell Cmake location of all headers
-    cmakeFlags = [
-        "-DEXTERNAL_INCLUDE_DIRECTORIES=${stdenv.lib.strings.makeSearchPathOutput "dev" "include" libosmium.buildInputs}"
-    ];
-
-    buildInputs = stdenv.lib.lists.concatLists[
-        # We want to check if dependencies exist using find_package
-        [
-          libosmium.buildInputs
-        ]
-        # dependencies 
-        [
-          libosmium
-        ]
-    ];
-
-    installPhase = ''
-        mkdir -p $out/bin
-        cp bin/hello-world $out/bin
-    '';
-}

script/test

@@ -15,6 +15,10 @@ nixargs=(
     "--max-jobs" "10"
 )
 
+targets=(
+
+)
+
 
 if [[ ! $OSTYPE =~ darwin ]]; then
     echo "Not testing on darwin"
@@ -23,11 +27,11 @@ if [[ ! $OSTYPE =~ darwin ]]; then
 else
     echo "Testing on darwin"
     echo "Not enabling sandbox, not running integration"
-    nixargs+=("-A" "niv-test")
+    targets+=("-A" "niv-test")
 fi
 
 # Build and create a root
-nix-build ${nixargs[@]}
+nix-build ${nixargs[@]} ${targets[@]}
 
 echo "Formatting"
 if ! nixpkgs-fmt --check . ; then
@@ -36,4 +40,12 @@ if ! nixpkgs-fmt --check . ; then
   exit 1
 fi
 
+echo "Building examples"
+for example in examples/*; do
+    echo " - $(basename $example)"
+    pushd $example
+    nix-build ${nixargs[@]}
+    popd
+done
+
 echo "all good"