Add MicroHs support.

.github/workflows/main.yml

@@ -96,6 +96,12 @@ jobs:
      - name: (WASM) Miso examples
        run: nix-build -A wasmExamples && ./result/bin/build.sh
 
+     - name: (x86) Example.hs (MicroHS 0.12.4.0)
+       run: cd micro/ && nix-shell --run 'mhs -temscripten Example -oout.js && qjs out.js'
+
+     - name: (JS) Example.hs (MicroHS 0.12.4.0)
+       run: cd micro/ && nix-shell --run 'mhs -r Example'
+
      - name: Nix garbage collect
        run: nix-collect-garbage -d
 

default.nix

@@ -98,4 +98,11 @@ with pkgs.haskell.lib;
   # bun
   inherit (pkgs)
     bun;
+
+  # MicroHs-Miso
+  inherit (pkgs)
+    microhs
+    microhs-env
+    microhs-wrapper;
+
 }

micro/Example.hs

@@ -0,0 +1,11 @@
+module Example(fac, main) where
+
+fac :: Int -> Int
+fac 0 = 1
+fac n = n * fac(n - 1)
+
+main :: IO ()
+main = do
+  let rs = map fac [1,2,3,10]
+  putStrLn "Some factorials"
+  print rs

micro/miso.cabal

@@ -0,0 +1,81 @@
+cabal-version:      3.0
+name:               miso
+version:            1.9.0.0
+synopsis:           A tasty Haskell front-end framework
+homepage:           https://haskell-miso.org
+license:            BSD-3-Clause
+license-file:       LICENSE
+author:             dmjio
+maintainer:         [email protected]
+copyright:          Copyright (c) 2016-2025 @dmjio
+category:           Web
+build-type:         Simple
+extra-doc-files:    CHANGELOG.md
+
+library
+  default-language:
+    Haskell2010
+  other-modules:
+    Miso.Concurrent
+    Miso.Delegate
+    Miso.Diff
+    Miso.Effect
+    Miso.Event
+    Miso.Event.Decoder
+    Miso.Event.Types
+    Miso.Exception
+    Miso.FFI
+    Miso.FFI.History
+    Miso.FFI.SSE
+    Miso.FFI.Storage
+    Miso.FFI.WebSocket
+    Miso.FFI.Internal
+    Miso.Html
+    Miso.Html.Element
+    Miso.Html.Event
+    Miso.Html.Property
+    Miso.Html.Types
+    Miso.Internal
+    Miso.Mathml
+    Miso.Mathml.Element
+    Miso.Render
+    Miso.Router
+    Miso.Run
+    Miso.Storage
+    Miso.Subscription
+    Miso.Subscription.History
+    Miso.Subscription.Keyboard
+    Miso.Subscription.Mouse
+    Miso.Subscription.WebSocket
+    Miso.Subscription.Window
+    Miso.Subscription.SSE
+    Miso.Svg.Attribute
+    Miso.Svg.Element
+    Miso.Svg.Event
+    Miso.Types
+    Miso.Util
+    Miso.WebSocket
+  exposed-modules:
+    Miso
+    Miso.Lens
+    Miso.Svg
+    Miso.String
+  ghc-options:
+    -Wall
+  hs-source-dirs:
+    ../src, ../text-src
+  build-depends:
+    aeson         < 2.3,
+    base          < 5,
+    bytestring    < 0.13,
+    containers    < 0.9,
+    http-api-data < 0.9,
+    http-media    < 0.9,
+    http-types    < 0.13,
+    jsaddle       < 0.10,
+    mtl           < 2.4,
+    network-uri   < 2.7,
+    servant       < 0.21,
+    tagsoup       < 0.15,
+    text          < 2.2,
+    transformers  < 0.7,

micro/shell.nix

@@ -0,0 +1 @@
+(import ../default.nix {}).microhs-env

nix/haskell/packages/ghc/default.nix

@@ -24,4 +24,7 @@ self: super:
   monad-logger = doJailbreak super.monad-logger;
   string-interpolate = doJailbreak super.string-interpolate;
   servant-server = doJailbreak super.servant-server;
+
+  /* microhs */
+  microhs = self.callCabal2nix "microhs" source.microhs {};
 }

nix/overlay.nix

@@ -24,6 +24,69 @@ self: super: {
           then import ./haskell/packages/ghcjs self
           else import ./haskell/packages/ghc self;
       };
+      ghc9101 = super.haskell.packages.ghc9101.override {
+        overrides = import ./haskell/packages/ghc self;
+      };
     };
   };
+
+  microhsTargetsConf =
+    super.writeTextFile {
+      name = "targets.conf";
+      text = ''
+        [default]
+        cc = "gcc"
+        ccflags = ""
+        conf = "unix-64"
+
+        [emscripten]
+        cc = "emcc"
+        ccflags = "-sALLOW_MEMORY_GROWTH -sTOTAL_STACK=5MB -sSINGLE_FILE -sENVIRONMENT=shell -sWASM=0"
+        conf = "unix-64"
+      '';
+    };
+
+  microhs =
+    super.stdenv.mkDerivation {
+      name = "MicroHs";
+      src = (import ../nix/source.nix super).microhs;
+      buildInputs = with super; [ emscripten ];
+      installPhase = ''
+        mkdir -p $out/{bin,share,lib/bin}
+
+        cp -v ./bin/mcabal $out/bin
+        cp -v ./bin/cpphs $out/bin
+        cp -v ./bin/mhs $out/bin
+        cp -rv ./lib $out
+
+        cp -rv ./generated $out
+        cp -rv ./boards $out
+        cp -rv ./paths $out
+        cp -rv ./doc $out
+        cp -rv ./src $out
+        cat ${self.microhsTargetsConf} > $out/targets.conf
+
+        cp README.md $out/share
+      '';
+    };
+
+  microhs-env = super.mkShell {
+    name = "microhs-env";
+    buildInputs = with self; [ microhs emscripten nodejs quickjs ];
+    # https://github.com/NixOS/nixpkgs/issues/139943#issuecomment-930432045
+    # dmj: Fix for using emcc in Darwin shell environment
+    #
+    # dmj: to compile /only/ JS, and work w/ QuickJS:
+    # $ emcc -sENVIRONMENT=shell -sWASM=0 main.c -oout.js && qjs out.js
+    shellHook = with super; ''
+      export MHSDIR=${self.microhs}
+      export CC=${super.emscripten}/bin/emcc
+      export PATH=$PATH:${self.microhs}/bin
+      mkdir -p ~/.emscripten_cache
+      chmod u+rwX -R ~/.emscripten_cache
+      cp -r ${super.emscripten}/share/emscripten/cache ~/.emscripten_cache
+      export EM_CACHE=~/.emscripten_cache
+    '';
+  };
+
 }

nix/source.nix

@@ -73,4 +73,12 @@ in
     rev = "d99f1965654568c0ced7bcd54c0d5083e08fce9c";
     sha256 = "1fz4wac1if0lc54gvga640dybwlchi1ybzxw8yjz5836674mdkid";
   };
+  microhs = fetchFromGitHub {
+    owner = "augustss";
+    repo = "microhs";
+    rev = "db0d3d12b0ee814441c6045bd680cc7d92a41375";
+    sha256 = "sha256-raTlZBQ5seYo/ez0Cg++nbQSLIKvSLLSqcCSL0svrLE=";
+    fetchSubmodules = true;
+  };
+
 }

shell.nix

@@ -4,7 +4,11 @@ with (import ./default.nix {});
 
 if pkg == "ghcjs"
 then miso-ghcjs.env
-else miso-ghc-9122.env.overrideAttrs (d: {
+else
+if pkg == "micro"
+then pkgs.microhs-env
+else
+ miso-ghc-9122.env.overrideAttrs (d: {
   shellHook = ''
     alias runner="${legacyPkgs.haskell.packages.ghc865.ghcid}/bin/ghcid -c 'cabal repl'"
   '';