more LLVM

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

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

cabal.project

@@ -1,4 +1,4 @@
-packages: .
+packages: haskell
 
 -- 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-runtime
+  subdir: c-expr-dsl c-expr-runtime hs-bindgen hs-bindgen-runtime
   --sha256: 0nrs3iq0l5ha5kxyhqnlmvgi7734pmzyp3zf7p8s1gb21ylh4sy0
 source-repository-package
   type: git

exe/GarnetRs/Wrapped.hs

@@ -1,41 +0,0 @@
--- 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

@@ -1,11 +0,0 @@
-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": 1771438068,
+        "lastModified": 1771121070,
-        "narHash": "sha256-nGBbXvEZVe/egCPVPFcu89RFtd8Rf6J+4RFoVCFec0A=",
+        "narHash": "sha256-aIlv7FRXF9q70DNJPI237dEDAznSKaXmL5lfK/Id/bI=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "b5090e53e9d68c523a4bb9ad42b4737ee6747597",
+        "rev": "a2812c19f1ed2e5ed5ce2ef7109798b575c180e1",
         "type": "github"
       },
       "original": {
@@ -115,24 +115,6 @@
         "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"
@@ -154,11 +136,11 @@
     "hackage": {
       "flake": false,
       "locked": {
-        "lastModified": 1771461386,
+        "lastModified": 1771289625,
-        "narHash": "sha256-93hCxhNOq9/HAggfTTurLhllI0IiEWZ35jk6i/X/qEo=",
+        "narHash": "sha256-ySABvJf2NaxGc1mPSkwKjC8So9S906UgOYZVzX35Ng8=",
         "owner": "input-output-hk",
         "repo": "hackage.nix",
-        "rev": "b4f4537825a4db29c10541a50d7eb6c848bf0dca",
+        "rev": "808af568b7e14e1eced115e65825d2f50a608008",
         "type": "github"
       },
       "original": {
@@ -170,11 +152,11 @@
     "hackage-for-stackage": {
       "flake": false,
       "locked": {
-        "lastModified": 1771461376,
+        "lastModified": 1771288450,
-        "narHash": "sha256-aEuZkBpTaU0XBFiaIomicJDoWQaw84rYfKXI/r17V/w=",
+        "narHash": "sha256-2tCS6CXMHPo4Jsh4JopbYBoQXnTTp8MdZVAqPVmOIq4=",
         "owner": "input-output-hk",
         "repo": "hackage.nix",
-        "rev": "ca611068e77f15b96ecf71fae827e491c0b2dc3b",
+        "rev": "3049efd880816a3bb98b7b5fb4062045fcddd474",
         "type": "github"
       },
       "original": {
@@ -200,7 +182,7 @@
         "type": "github"
       }
     },
-    "haskell-nix": {
+    "haskellNix": {
       "inputs": {
         "HTTP": "HTTP",
         "cabal-32": "cabal-32",
@@ -228,7 +210,7 @@
         "hpc-coveralls": "hpc-coveralls",
         "iserv-proxy": "iserv-proxy",
         "nixpkgs": [
-          "haskell-nix",
+          "haskellNix",
           "nixpkgs-unstable"
         ],
         "nixpkgs-2305": "nixpkgs-2305",
@@ -242,11 +224,11 @@
         "stackage": "stackage"
       },
       "locked": {
-        "lastModified": 1771462666,
+        "lastModified": 1771289806,
-        "narHash": "sha256-z+pJFzbYa1ulNDUZdb0qLVVAdE0dqpnE51jqh2chA7c=",
+        "narHash": "sha256-s60Kb3cYr0t6LDQ/LmJr5vQN8Z4IY1Vfwq2keZW0VOM=",
         "owner": "input-output-hk",
         "repo": "haskell.nix",
-        "rev": "857ba7b65d9c1a8765ad1599834a8fe71cb09981",
+        "rev": "3331ba591ae02a41c638aeb6bea91d268b34cf8e",
         "type": "github"
       },
       "original": {
@@ -525,27 +507,6 @@
         "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": {
@@ -563,39 +524,6 @@
         "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,
@@ -692,21 +620,6 @@
         "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,
@@ -744,11 +657,10 @@
       "inputs": {
         "crane": "crane",
         "flake-utils": "flake-utils",
-        "haskell-nix": "haskell-nix",
+        "haskellNix": "haskellNix",
         "hls-2-13": "hls-2-13",
-        "hs-bindgen": "hs-bindgen",
         "nixpkgs": [
-          "haskell-nix",
+          "haskellNix",
           "nixpkgs-2511"
         ],
         "rust-overlay": "rust-overlay"
@@ -761,11 +673,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1771470520,
+        "lastModified": 1771297684,
-        "narHash": "sha256-PvytHcaYN5cPUll7FB70mXv1rRsIBRmu47fFfq3haxA=",
+        "narHash": "sha256-wieWskQxZLPlNXX06JEB0bMoS/ZYQ89xBzF0RL9lyLs=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "a1d4cc1f264c45d3745af0d2ca5e59d460e58777",
+        "rev": "755d3669699a7c62aef35af187d75dc2728cfd85",
         "type": "github"
       },
       "original": {
@@ -777,11 +689,11 @@
     "stackage": {
       "flake": false,
       "locked": {
-        "lastModified": 1771460325,
+        "lastModified": 1771287554,
-        "narHash": "sha256-RRsGO7QVyuBtUTVqDiB7CYvFruj0Z/yxZK1JarkTqI4=",
+        "narHash": "sha256-76Kd5c2D4O8yL48eAejlGZlpQ/Exxnsz3V7qW+RkFzE=",
         "owner": "input-output-hk",
         "repo": "stackage.nix",
-        "rev": "29c0dcc517e04be238023064412312ad4443ddb2",
+        "rev": "e62b9d6269c6abfd8b976826da0dcc37f0a57010",
         "type": "github"
       },
       "original": {

flake.nix

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

generate-bindings

@@ -3,15 +3,23 @@ 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, cbindgen, hs-bindgen-cli).
+# Prerequisites: run inside the Nix dev shell (provides gcc, cabal, etc.)
+# cbindgen is fetched via `nix run nixpkgs#rust-cbindgen`.
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 RUST_DIR="$SCRIPT_DIR/rust"
-HASKELL_DIR="$SCRIPT_DIR"
+HASKELL_DIR="$SCRIPT_DIR/haskell"
 HEADER_NAME="garnet_rs.h"
 HEADER="$RUST_DIR/$HEADER_NAME"
 
@@ -21,7 +29,7 @@ cargo build --manifest-path "$RUST_DIR/Cargo.toml"
 
 # --- Step 2: Generate C header with cbindgen ---
 echo "=== Running cbindgen ==="
-cbindgen \
+nix run nixpkgs#rust-cbindgen -- \
   --lang c \
   --crate garnet-rs \
   --output "$HEADER" \
@@ -89,7 +97,8 @@ pending_enum && /^typedef [A-Za-z0-9_]+ / {
 }
 
 { print }
-' "$HEADER" > "${HEADER}.tmp" && mv "${HEADER}.tmp" "$HEADER"
+' "$HEADER" > "${HEADER}.tmp"
+mv "${HEADER}.tmp" "$HEADER"
 
 echo "  Patched header at $HEADER"
 
@@ -115,7 +124,7 @@ fi
 
 # --- Step 5: Run hs-bindgen ---
 echo "=== Running hs-bindgen ==="
-hs-bindgen-cli preprocess \
+cabal run -- hs-bindgen-cli preprocess \
   --overwrite-files --create-output-dirs \
   --unique-id com.garnet --enable-record-dot \
   --hs-output-dir "$HASKELL_DIR/generated" --module GarnetRs \
@@ -124,4 +133,4 @@ hs-bindgen-cli preprocess \
 
 echo "=== Done ==="
 echo "Generated Haskell bindings in $HASKELL_DIR/generated/"
-echo "Run 'cabal run' to test."
+echo "Run 'cabal run garnet' to test."

haskell/LICENSE

@@ -0,0 +1,30 @@
+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

@@ -0,0 +1,32 @@
+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

haskell/garnet.cabal

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

rust/lib.rs

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