Move Haskell package to top level

See https://sraka.xyz/posts/hs-bindgen-introduction.html.

For now, this is a shell-based workflow, rather than using Nix to build everything, i.e. `nix develop` works but `nix build` doesn't. And `cargo build` has to be called manually to create the C library, rather than `cabal` being clever enough to invoke it itself.

We ran `cargo cabal init` from the `rust` directory (`nix shell github:yvan-sraka/cargo-cabal`), which generated `hsbindgen.toml` (which we use), and `Setup.lhs` (which just added `extra-lib-dirs`, and with the wrong paths, so we dspecify those statically instead in `garnet.cabal`). We also follow its advice to use `staticlib`.

Also, after we ran the first `cargo build` (requiring a `mkdir rust/src` before it would run), we took the generated the Haskell file, and moved the main contents in to `Main.hs` manually.

.gitignore

@@ -1,3 +1,3 @@
-dist*/
+dist*
 result
 target

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "inputs/real"]
-	path = inputs/private
-	url = git@github.com:georgefst/aoc-private-inputs.git

cabal.project

@@ -1,4 +1,4 @@
-packages: haskell
+packages: .
 
 -- TODO a total hack
 package garnet
@@ -15,7 +15,7 @@ source-repository-package
   type: git
   location: https://github.com/well-typed/hs-bindgen
   tag: e2a9260678d9fa76dab602a5a07927acada3be4f
-  subdir: c-expr-dsl c-expr-runtime hs-bindgen hs-bindgen-runtime
+  subdir: c-expr-dsl c-expr-runtime hs-bindgen-runtime
   --sha256: 0nrs3iq0l5ha5kxyhqnlmvgi7734pmzyp3zf7p8s1gb21ylh4sy0
 source-repository-package
   type: git

exe/GarnetRs/Wrapped.hs

@@ -0,0 +1,41 @@
+-- TODO automate this sort of high level wrapper boilerplate
+-- or look at upstream plans: https://github.com/well-typed/hs-bindgen/issues?q=state%3Aopen%20label%3A%22highlevel%22
+module GarnetRs.Wrapped (
+    T (..),
+    Shape (..),
+    hello,
+    helloStruct,
+    helloShape,
+) where
+
+import Data.ByteString
+import Data.Word
+import Foreign
+import Foreign.C
+import GarnetRs qualified as Raw
+import GarnetRs.Safe qualified as Raw
+import HsBindgen.Runtime.PtrConst
+
+data T = T
+    { a :: Bool
+    , b :: Word8
+    }
+convertT :: T -> Raw.T
+convertT T{a, b} = Raw.T{a = CBool $ fromBool a, b}
+
+data Shape
+    = Circle CDouble
+    | Rectangle CDouble CDouble
+convertShape :: Shape -> Raw.Shape
+convertShape = \case
+    Circle r -> Raw.Shape (Raw.Shape_Tag 0) $ Raw.set_shape_body_circle $ Raw.Circle_Body r
+    Rectangle w h -> Raw.Shape (Raw.Shape_Tag 1) $ Raw.set_shape_body_rectangle $ Raw.Rectangle_Body w h
+
+hello :: ByteString -> IO ()
+hello s = useAsCString s $ Raw.hello . unsafeFromPtr
+
+helloStruct :: T -> IO ()
+helloStruct = Raw.hello_struct . convertT
+
+helloShape :: Shape -> IO ()
+helloShape = Raw.hello_shape . convertShape

exe/Main.hs

@@ -0,0 +1,11 @@
+module Main (main) where
+
+import GarnetRs.Wrapped
+
+main :: IO ()
+main = do
+    hello "Haskell"
+    helloStruct T{a = True, b = 42}
+    helloStruct T{a = False, b = maxBound}
+    helloShape $ Circle 3.14
+    helloShape $ Rectangle 10.0 5.0

flake.lock

@@ -85,11 +85,11 @@
     },
     "crane": {
       "locked": {
-        "lastModified": 1771121070,
+        "lastModified": 1771438068,
-        "narHash": "sha256-aIlv7FRXF9q70DNJPI237dEDAznSKaXmL5lfK/Id/bI=",
+        "narHash": "sha256-nGBbXvEZVe/egCPVPFcu89RFtd8Rf6J+4RFoVCFec0A=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "a2812c19f1ed2e5ed5ce2ef7109798b575c180e1",
+        "rev": "b5090e53e9d68c523a4bb9ad42b4737ee6747597",
         "type": "github"
       },
       "original": {
@@ -115,6 +115,24 @@
         "type": "github"
       }
     },
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1769996383,
+        "narHash": "sha256-AnYjnFWgS49RlqX7LrC4uA+sCCDBj0Ry/WOJ5XWAsa0=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "57928607ea566b5db3ad13af0e57e921e6b12381",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -136,11 +154,11 @@
     "hackage": {
       "flake": false,
       "locked": {
-        "lastModified": 1771289625,
+        "lastModified": 1771461386,
-        "narHash": "sha256-ySABvJf2NaxGc1mPSkwKjC8So9S906UgOYZVzX35Ng8=",
+        "narHash": "sha256-93hCxhNOq9/HAggfTTurLhllI0IiEWZ35jk6i/X/qEo=",
         "owner": "input-output-hk",
         "repo": "hackage.nix",
-        "rev": "808af568b7e14e1eced115e65825d2f50a608008",
+        "rev": "b4f4537825a4db29c10541a50d7eb6c848bf0dca",
         "type": "github"
       },
       "original": {
@@ -152,11 +170,11 @@
     "hackage-for-stackage": {
       "flake": false,
       "locked": {
-        "lastModified": 1771288450,
+        "lastModified": 1771461376,
-        "narHash": "sha256-2tCS6CXMHPo4Jsh4JopbYBoQXnTTp8MdZVAqPVmOIq4=",
+        "narHash": "sha256-aEuZkBpTaU0XBFiaIomicJDoWQaw84rYfKXI/r17V/w=",
         "owner": "input-output-hk",
         "repo": "hackage.nix",
-        "rev": "3049efd880816a3bb98b7b5fb4062045fcddd474",
+        "rev": "ca611068e77f15b96ecf71fae827e491c0b2dc3b",
         "type": "github"
       },
       "original": {
@@ -182,7 +200,7 @@
         "type": "github"
       }
     },
-    "haskellNix": {
+    "haskell-nix": {
       "inputs": {
         "HTTP": "HTTP",
         "cabal-32": "cabal-32",
@@ -210,7 +228,7 @@
         "hpc-coveralls": "hpc-coveralls",
         "iserv-proxy": "iserv-proxy",
         "nixpkgs": [
-          "haskellNix",
+          "haskell-nix",
           "nixpkgs-unstable"
         ],
         "nixpkgs-2305": "nixpkgs-2305",
@@ -224,11 +242,11 @@
         "stackage": "stackage"
       },
       "locked": {
-        "lastModified": 1771289806,
+        "lastModified": 1771462666,
-        "narHash": "sha256-s60Kb3cYr0t6LDQ/LmJr5vQN8Z4IY1Vfwq2keZW0VOM=",
+        "narHash": "sha256-z+pJFzbYa1ulNDUZdb0qLVVAdE0dqpnE51jqh2chA7c=",
         "owner": "input-output-hk",
         "repo": "haskell.nix",
-        "rev": "3331ba591ae02a41c638aeb6bea91d268b34cf8e",
+        "rev": "857ba7b65d9c1a8765ad1599834a8fe71cb09981",
         "type": "github"
       },
       "original": {
@@ -507,6 +525,27 @@
         "type": "github"
       }
     },
+    "hs-bindgen": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "libclang-bindings-src": "libclang-bindings-src",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1770394582,
+        "narHash": "sha256-erbj5xqqJ/M0c99G0vjZvJtvoxYJ1PG7DDkw15MVLK8=",
+        "owner": "well-typed",
+        "repo": "hs-bindgen",
+        "rev": "e2a9260678d9fa76dab602a5a07927acada3be4f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "well-typed",
+        "ref": "release-0.1-alpha",
+        "repo": "hs-bindgen",
+        "type": "github"
+      }
+    },
     "iserv-proxy": {
       "flake": false,
       "locked": {
@@ -524,6 +563,39 @@
         "type": "github"
       }
     },
+    "libclang-bindings-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1770274896,
+        "narHash": "sha256-JnxJBo2L4URFD8JbpjnPG/ej/xKFe7y5ZpjnvIztwAM=",
+        "owner": "well-typed",
+        "repo": "libclang",
+        "rev": "155642a4a4a9f0414a058a8f08f39aa6c7bb57ed",
+        "type": "github"
+      },
+      "original": {
+        "owner": "well-typed",
+        "repo": "libclang",
+        "rev": "155642a4a4a9f0414a058a8f08f39aa6c7bb57ed",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1770169770,
+        "narHash": "sha256-awR8qIwJxJJiOmcEGgP2KUqYmHG4v/z8XpL9z8FnT1A=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "aa290c9891fa4ebe88f8889e59633d20cc06a5f2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs-2305": {
       "locked": {
         "lastModified": 1705033721,
@@ -620,6 +692,21 @@
         "type": "github"
       }
     },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1769909678,
+        "narHash": "sha256-cBEymOf4/o3FD5AZnzC3J9hLbiZ+QDT/KDuyHXVJOpM=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "72716169fe93074c333e8d0173151350670b824c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
     "nixpkgs-unstable": {
       "locked": {
         "lastModified": 1764587062,
@@ -657,10 +744,11 @@
       "inputs": {
         "crane": "crane",
         "flake-utils": "flake-utils",
-        "haskellNix": "haskellNix",
+        "haskell-nix": "haskell-nix",
         "hls-2-13": "hls-2-13",
+        "hs-bindgen": "hs-bindgen",
         "nixpkgs": [
-          "haskellNix",
+          "haskell-nix",
           "nixpkgs-2511"
         ],
         "rust-overlay": "rust-overlay"
@@ -673,11 +761,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1771297684,
+        "lastModified": 1771470520,
-        "narHash": "sha256-wieWskQxZLPlNXX06JEB0bMoS/ZYQ89xBzF0RL9lyLs=",
+        "narHash": "sha256-PvytHcaYN5cPUll7FB70mXv1rRsIBRmu47fFfq3haxA=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "755d3669699a7c62aef35af187d75dc2728cfd85",
+        "rev": "a1d4cc1f264c45d3745af0d2ca5e59d460e58777",
         "type": "github"
       },
       "original": {
@@ -689,11 +777,11 @@
     "stackage": {
       "flake": false,
       "locked": {
-        "lastModified": 1771287554,
+        "lastModified": 1771460325,
-        "narHash": "sha256-76Kd5c2D4O8yL48eAejlGZlpQ/Exxnsz3V7qW+RkFzE=",
+        "narHash": "sha256-RRsGO7QVyuBtUTVqDiB7CYvFruj0Z/yxZK1JarkTqI4=",
         "owner": "input-output-hk",
         "repo": "stackage.nix",
-        "rev": "e62b9d6269c6abfd8b976826da0dcc37f0a57010",
+        "rev": "29c0dcc517e04be238023064412312ad4443ddb2",
         "type": "github"
       },
       "original": {

flake.nix

@@ -1,28 +1,22 @@
 {
   inputs = {
-    haskellNix.url = "github:input-output-hk/haskell.nix";
+    haskell-nix.url = "github:input-output-hk/haskell.nix";
     hls-2-13 = { url = "github:haskell/haskell-language-server/2.13.0.0"; flake = false; };
-    nixpkgs.follows = "haskellNix/nixpkgs-2511";
+    nixpkgs.follows = "haskell-nix/nixpkgs-2511";
     flake-utils.url = "github:numtide/flake-utils";
     crane.url = "github:ipetkov/crane";
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    hs-bindgen.url = "github:well-typed/hs-bindgen/release-0.1-alpha";
   };
   outputs =
-    { self
+    inputs@{ nixpkgs, ... }:
-    , nixpkgs
+    inputs.flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
-    , flake-utils
-    , haskellNix
-    , hls-2-13
-    , crane
-    , rust-overlay
-    }:
-    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
     let
       overlays = [
-        haskellNix.overlay
+        inputs.haskell-nix.overlay
         (final: _prev: {
           hixProject =
             final.haskell-nix.hix.project {
@@ -33,20 +27,18 @@
               shell.tools.cabal = "latest";
               shell.withHoogle = false;
               shell.tools.haskell-language-server = {
-                src = hls-2-13;
+                src = inputs.hls-2-13;
                 sha256map = {
                   "https://github.com/snowleopard/alga"."d4e43fb42db05413459fb2df493361d5a666588a" = "0s1mlnl64wj7pkg3iipv5bb4syy3bhxwqzqv93zqlvkyfn64015i";
                 };
               };
             };
         })
-        (import rust-overlay)
+        (import inputs.rust-overlay)
       ];
-      pkgs = import nixpkgs { inherit system overlays; inherit (haskellNix) config; };
+      pkgs = import nixpkgs { inherit system overlays; inherit (inputs.haskell-nix) config; };
       haskell = pkgs.hixProject.flake { };
-      # TODO we're not getting Rust libs from Nix
+      rust = (inputs.crane.mkLib pkgs).overrideToolchain (p: p.rust-bin.selectLatestNightlyWith (
-      # i.e. running `cargo clean && cargo build` rebuilds dependencies
-      rust = (crane.mkLib pkgs).overrideToolchain (p: p.rust-bin.selectLatestNightlyWith (
         toolchain: toolchain.default.override {
           extensions = [ "rust-src" ];
           targets = [ "x86_64-unknown-linux-gnu" ];
@@ -60,13 +52,12 @@
           (rust.devShell { })
         ];
         packages = with pkgs; [
-          llvmPackages.libclang
-          llvmPackages.llvm
           bacon
           ghcid
+          inputs.hs-bindgen.packages.${system}.hs-bindgen-cli
           rust-analyzer
+          rust-cbindgen
         ];
       };
-    }
+    });
-    );
 }

garnet.cabal

@@ -1,9 +1,11 @@
 cabal-version: 3.0
 name: garnet
 version: 0.1.0.0
-license-file: LICENSE
+license: BSD-3-Clause
 author: Patrick Aldis
-maintainer: patricktaldis@gmail.com
+maintainer:
+    george.thomas@obsidian.systems
+    patrick.aldis@obsidian.systems
 
 library garnet-generated
     hs-source-dirs: generated
@@ -21,6 +23,8 @@ library garnet-generated
 
 executable garnet
     main-is: Main.hs
+    other-modules:
+        GarnetRs.Wrapped
     hs-source-dirs: exe
     default-language: GHC2024
     default-extensions:

generate-bindings

@@ -3,23 +3,15 @@ set -euo pipefail
 
 # TODO this is a complete vibe-coded hack, but the header patching at least is crucial
 
-# TODO fully-vibed hack
-# we should do a few things quite differently anyway
-
-# generated Haskell code shouldn't be checked in as it's not portable
-# does the TH way of using `hs-bindgen` help here?
-# I guess we shouldn't check in the generated C header either
-
 # Generate Haskell FFI bindings from Rust source code.
 #
 # Pipeline: cargo build -> cbindgen -> patch header -> hs-bindgen
 #
-# Prerequisites: run inside the Nix dev shell (provides gcc, cabal, etc.)
+# Prerequisites: run inside the Nix dev shell (provides gcc, cabal, cbindgen, hs-bindgen-cli).
-# cbindgen is fetched via `nix run nixpkgs#rust-cbindgen`.
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 RUST_DIR="$SCRIPT_DIR/rust"
-HASKELL_DIR="$SCRIPT_DIR/haskell"
+HASKELL_DIR="$SCRIPT_DIR"
 HEADER_NAME="garnet_rs.h"
 HEADER="$RUST_DIR/$HEADER_NAME"
 
@@ -29,7 +21,7 @@ cargo build --manifest-path "$RUST_DIR/Cargo.toml"
 
 # --- Step 2: Generate C header with cbindgen ---
 echo "=== Running cbindgen ==="
-nix run nixpkgs#rust-cbindgen -- \
+cbindgen \
   --lang c \
   --crate garnet-rs \
   --output "$HEADER" \
@@ -97,8 +89,7 @@ pending_enum && /^typedef [A-Za-z0-9_]+ / {
 }
 
 { print }
-' "$HEADER" > "${HEADER}.tmp"
+' "$HEADER" > "${HEADER}.tmp" && mv "${HEADER}.tmp" "$HEADER"
-mv "${HEADER}.tmp" "$HEADER"
 
 echo "  Patched header at $HEADER"
 
@@ -124,7 +115,7 @@ fi
 
 # --- Step 5: Run hs-bindgen ---
 echo "=== Running hs-bindgen ==="
-cabal run -- hs-bindgen-cli preprocess \
+hs-bindgen-cli preprocess \
   --overwrite-files --create-output-dirs \
   --unique-id com.garnet --enable-record-dot \
   --hs-output-dir "$HASKELL_DIR/generated" --module GarnetRs \
@@ -133,4 +124,4 @@ cabal run -- hs-bindgen-cli preprocess \
 
 echo "=== Done ==="
 echo "Generated Haskell bindings in $HASKELL_DIR/generated/"
-echo "Run 'cabal run garnet' to test."
+echo "Run 'cabal run' to test."

haskell/LICENSE

@@ -1,30 +0,0 @@
-Copyright (c) 2025, George Thomas
-
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-    * Redistributions of source code must retain the above copyright
-      notice, this list of conditions and the following disclaimer.
-
-    * Redistributions in binary form must reproduce the above
-      copyright notice, this list of conditions and the following
-      disclaimer in the documentation and/or other materials provided
-      with the distribution.
-
-    * Neither the name of George Thomas nor the names of other
-      contributors may be used to endorse or promote products derived
-      from this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

haskell/exe/Main.hs

@@ -1,32 +0,0 @@
-module Main (main) where
-
-import Data.ByteString
-import Data.Word
-import Foreign.C
-import GarnetRs
-import GarnetRs.Safe
-import HsBindgen.Runtime.PtrConst
-import Unsafe.Coerce
-
-main :: IO ()
-main = do
-    useAsCString "Haskell" $ hello . unsafeFromPtr
-    hello_struct $ convertT T'{a = True, b = 42}
-    hello_struct $ convertT T'{a = False, b = 42}
-    hello_shape $ convertShape $ Circle 3.14
-    hello_shape $ convertShape $ Rectangle 10.0 5.0
-
-data T' = T'
-    { a :: Bool
-    , b :: Word8
-    }
-convertT T'{a, b} =
-    -- T{a = CBool $ unsafeCoerce @Bool @Word8 a, b}
-    T{a = CBool $ fromIntegral $ fromEnum a, b}
-
-data Shape'
-    = Circle CDouble
-    | Rectangle CDouble CDouble
-convertShape = \case
-    Circle r -> Shape (Shape_Tag 0) $ set_shape_body_circle $ Circle_Body r
-    Rectangle w h -> Shape (Shape_Tag 1) $ set_shape_body_rectangle $ Rectangle_Body w h

rust/lib.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use std::ffi::{CStr, c_char};
 
 fn say_hello(name: &str) {
@@ -21,7 +23,6 @@ extern "C" fn hello_struct(t: T) -> () {
 }
 
 #[repr(C, u8)]
-#[allow(dead_code)]
 #[derive(Debug)]
 enum Shape {
     Circle { radius: f64 },