Initial commit

Initial commit of ghc-wasm-reflex-examples forked from
ghc-wasm-miso-examples.

Co-authored-by: Cheng Shao <terrorjack@type.dance>

.github/workflows/build.yml

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+name: build
+
+on:
+  merge_group:
+  pull_request:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  nix-build:
+    name: nix-build
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: install-nix
+        uses: DeterminateSystems/nix-installer-action@v15
+
+      - name: build-frontend
+        run: |
+          nix develop --command bash -c "cd frontend && wasm32-wasi-cabal update && exec ./build.sh --debuginfo --low-memory-unused --converge --gufa --flatten --rereloop -Oz"
+
+  ghcup-build:
+    name: ghcup-build
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: install-happy
+        run: |
+          cabal path --installdir >> "$GITHUB_PATH"
+          cabal update -z
+          cabal install -z happy
+
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: ghc-wasm-meta
+        run: |
+          pushd "$(mktemp -d)"
+          curl -f -L --retry 5 https://gitlab.haskell.org/ghc/ghc-wasm-meta/-/archive/master/ghc-wasm-meta-master.tar.gz | tar xz --strip-components=1
+          SKIP_GHC=1 ./setup.sh
+          ~/.ghc-wasm/add_to_github_path.sh
+          popd
+
+      - name: cabal
+        run: |
+          ghcup config add-release-channel https://raw.githubusercontent.com/haskell/ghcup-metadata/develop/ghcup-prereleases-0.0.8.yaml
+          ghcup install cabal --set 3.15.0.0.2024.10.3
+
+      - name: wasm32-wasi-ghc
+        run: |
+          ghcup config add-release-channel https://raw.githubusercontent.com/haskell/ghcup-metadata/develop/ghcup-cross-0.0.8.yaml
+          ghcup install ghc --set wasm32-wasi-9.10.1.20241021 -- $CONFIGURE_ARGS
+
+      - name: build-frontend
+        run: |
+          cd frontend
+          cabal \
+            --with-compiler=wasm32-wasi-ghc \
+            --with-hc-pkg=wasm32-wasi-ghc-pkg \
+            --with-hsc2hs=wasm32-wasi-hsc2hs \
+            update
+          ./build.sh --debuginfo --low-memory-unused --converge --gufa --flatten --rereloop -Oz
+
+  non-nix-build:
+    name: non-nix-build
+    runs-on: ubuntu-latest
+    permissions:
+      pages: write
+      id-token: write
+    steps:
+
+      - name: install-happy
+        run: |
+          cabal path --installdir >> "$GITHUB_PATH"
+          cabal update -z
+          cabal install -z happy
+
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: ghc-wasm-meta
+        run: |
+          pushd "$(mktemp -d)"
+          curl -f -L --retry 5 https://gitlab.haskell.org/ghc/ghc-wasm-meta/-/archive/master/ghc-wasm-meta-master.tar.gz | tar xz --strip-components=1
+          ./setup.sh
+          ~/.ghc-wasm/add_to_github_path.sh
+          popd
+        env:
+          FLAVOUR: '9.10'
+
+      - name: build-frontend
+        run: |
+          cd frontend
+          ./build.sh --debuginfo --low-memory-unused --converge --gufa --flatten --rereloop -Oz
+
+      - name: upload-pages-artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: frontend/dist
+          retention-days: 90
+
+      - name: deploy-pages
+        uses: actions/deploy-pages@v4

.gitignore

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+dist-newstyle/

LICENSE

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+MIT License
+
+Copyright (c) Tweag I/O Limited.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# `ghc-wasm-reflex-examples`
+
+[![Chat on Matrix](https://matrix.to/img/matrix-badge.svg)](https://matrix.to/#/#haskell-wasm:matrix.terrorjack.com)
+
+The GHC wasm backend supports the
+[JSFFI](https://ghc.gitlab.haskell.org/ghc/doc/users_guide/wasm.html#javascript-ffi-in-the-wasm-backend)
+feature, allowing Haskell wasm apps to interop with JavaScript
+seamlessly in the browser. This repo contains an example to
+demonstrate this ability based on the
+[`reflex`](https://reflex-frp.org/) frontend framework as well as an
+experimental [`jsaddle-wasm`](https://github.com/amesgen/jsaddle-wasm)
+library under the hood.
+
+See also:
+[`ghc-wasm-miso-examples`](https://github.com/tweag/ghc-wasm-miso-examples)
+
+## Live demo
+
+- [reflex-todomvc](https://tweag.github.io/ghc-wasm-reflex-examples/reflex-todomvc.html)
+
+## Building
+
+### With nix
+
+Within the `nix develop` shell:
+
+```sh
+cd frontend
+wasm32-wasi-cabal update
+./build.sh
+```
+
+If you pass additional arguments to `build.sh`, they will be
+redirected to `wasm-opt`, otherwise a dev build without `wasm-opt`
+will be performed.
+
+The artifacts will be available in `frontend/dist`.
+
+### Without nix
+
+You can set up the toolchain by either:
+
+- Using
+  [`ghc-wasm-meta`](https://gitlab.haskell.org/ghc/ghc-wasm-meta#getting-started-without-nix)
+  directly to set up ghc 9.10
+- Using [`ghcup`](https://www.haskell.org/ghcup/guide/#cross-support)
+  to set up ghc 9.10 (9.10.1.20241021 or later, with TemplateHaskell
+  support) and cabal >=3.14.
+
+Then:
+
+```sh
+source ~/.ghc-wasm/env
+cd frontend
+./build.sh
+```
+
+## Acknowledgements
+
+The examples are vendored and modified from the following projects:
+
+- reflex-todomvc: based on https://github.com/reflex-frp/reflex-todomvc

app/App.hs

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+module App (start) where
+
+import GHC.Wasm.Prim
+import Language.Javascript.JSaddle (JSM)
+import Reflex.TodoMVC qualified
+
+start :: JSString -> JSM ()
+start e =
+  case fromJSString e of
+    "reflex-todomvc" -> Reflex.TodoMVC.main
+    _ -> fail "unknown example"

app/Main.hs

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+module MyMain (main) where
+
+import App (start)
+import GHC.Wasm.Prim
+import Language.Javascript.JSaddle.Wasm qualified as JSaddle.Wasm
+
+foreign export javascript "hs_start" main :: JSString -> IO ()
+
+main :: JSString -> IO ()
+main e = JSaddle.Wasm.run $ start e

cabal.project

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+packages: . reflex-todomvc
+
+index-state: 2024-11-11T12:54:21Z
+
+if arch(wasm32)
+  -- Required for TemplateHaskell. When using wasm32-wasi-cabal from
+  -- ghc-wasm-meta, this is superseded by the global cabal.config.
+  shared: True
+
+  -- https://github.com/haskellari/time-compat/issues/37
+  -- Older versions of time don't build on WASM.
+  constraints: time installed
+  allow-newer: time
+
+  -- https://github.com/haskellari/splitmix/pull/73
+  source-repository-package
+    type: git
+    location: https://github.com/amesgen/splitmix
+    tag: 5f5b766d97dc735ac228215d240a3bb90bc2ff75
+
+package aeson
+  flags: -ordered-keymap
+
+-- for reflex-frp
+
+-- GHC 9.10 compat
+source-repository-package
+  type: git
+  location: https://github.com/amesgen/reflex-dom
+  tag: e43e0525d643f656a0a5b0f10e13e2a04712cd4e
+  subdir: reflex-dom-core
+
+allow-newer: dependent-sum-template:template-haskell

flake.nix

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+{
+  inputs = {
+    ghc-wasm-meta.url = "gitlab:ghc/ghc-wasm-meta?host=gitlab.haskell.org";
+  };
+  outputs = inputs: inputs.ghc-wasm-meta.inputs.flake-utils.lib.eachDefaultSystem (system:
+    let pkgs = inputs.ghc-wasm-meta.inputs.nixpkgs.legacyPackages.${system};
+    in
+    {
+      devShells.default = pkgs.mkShell {
+        packages = [
+          inputs.ghc-wasm-meta.packages.${system}.all_9_10
+        ];
+      };
+    });
+}

frontend/.gitignore

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+node_modules/
+dist/
+ghc_wasm_jsffi.js