Switch to Template Haskell mode for hs-bindgen

Avoid IO for tree sum
Make Rust tree type polymorphic
2026-02-20 09:08:16 +00:00 · 2026-02-19 21:35:35 +00:00 · 2026-02-19 21:28:00 +00:00 · 2026-02-19 21:18:37 +00:00 · 2026-02-19 21:11:58 +00:00 · 2026-02-19 21:11:23 +00:00
14 changed files with 179 additions and 1124 deletions
--- a/cabal.project
+++ b/cabal.project
@ -7,7 +7,7 @@ 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
--- a/exe/Main.hs
+++ b/exe/Main.hs
@ -10,3 +10,4 @@ main = do
    helloShape $ Circle 3.14
    helloShape $ Rectangle 10.0 5.0
    putStrLn $ "3 + 4 = " <> show (add 3 4)
+    putStrLn $ "Tree sum: " <> show (sumTree (Fork (Fork (Leaf 1) (Fork (Leaf 2) (Leaf 3))) (Leaf 4)))
--- a/flake.lock
+++ b/flake.lock
@ -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"
@ -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,
@ -746,7 +659,6 @@
        "flake-utils": "flake-utils",
        "haskell-nix": "haskell-nix",
        "hls-2-13": "hls-2-13",
-        "hs-bindgen": "hs-bindgen",
        "nixpkgs": [
          "haskell-nix",
          "nixpkgs-2511"
--- a/flake.nix
+++ b/flake.nix
@ -9,7 +9,6 @@
      url = "github:oxalica/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
-    hs-bindgen.url = "github:well-typed/hs-bindgen/release-0.1-alpha";
  };
  outputs =
    inputs@{ nixpkgs, ... }:
@ -54,7 +53,7 @@
        packages = with pkgs; [
          bacon
          ghcid
-          inputs.hs-bindgen.packages.${system}.hs-bindgen-cli
+          llvmPackages.libclang
          rust-analyzer
          rust-cbindgen
        ];
--- a/garnet.cabal
+++ b/garnet.cabal
@ -7,25 +7,7 @@ maintainer:
    george.thomas@obsidian.systems
    patrick.aldis@obsidian.systems

-library garnet-generated
-    hs-source-dirs: generated
-    exposed-modules:
-        GarnetRs
-        GarnetRs.Safe
-        GarnetRs.Unsafe
-        GarnetRs.FunPtr
-    default-language: Haskell2010
-    extra-bundled-libraries: garnet_rs
-    build-depends:
-        base,
-        hs-bindgen-runtime,
-        primitive,
-
-executable garnet
-    main-is: Main.hs
-    other-modules:
-        GarnetRs.Wrapped
-    hs-source-dirs: exe
+common common
    default-language: GHC2024
    default-extensions:
        BlockArguments
@ -45,11 +27,35 @@ executable garnet
    ghc-options:
        -Wall
        -fdefer-type-errors
+    build-depends:
+        bytestring,
+        extra,
+        mtl,
+        process,
+        text,
+
+library
+    import: common
+    exposed-modules:
+        GarnetRs.Raw
+        GarnetRs.Wrapped
+    hs-source-dirs: lib
+    extra-bundled-libraries: garnet_rs
+    build-depends:
+        base,
+        hs-bindgen,
+        hs-bindgen-runtime,
+        primitive,
+        template-haskell,
+
+executable garnet
+    import: common
+    main-is: Main.hs
+    hs-source-dirs: exe
+    ghc-options:
        -threaded
        -rtsopts
        -with-rtsopts=-N
    build-depends:
-        base >= 4.14,
-        bytestring,
-        garnet-generated,
-        hs-bindgen-runtime,
+        base,
+        garnet,
--- a/43
+++ b/43
@ -3,20 +3,21 @@ set -euo pipefail

 # TODO this is a complete vibe-coded hack, but the header patching at least is crucial

-# Generate Haskell FFI bindings from Rust source code.
+# Prepare Rust artifacts and C header for hs-bindgen.
 #
 # Pipeline:
 #   1. cargo build       - build the Rust static library
 #   2. cbindgen           - generate a C header from the Rust source
 #   3. awk                - patch the header for hs-bindgen compatibility
-#   4. hs-bindgen-cli     - generate Haskell FFI modules from the C header
-#   5. cabal configure    - point Cabal at the Rust build artifacts
+#   4. cabal configure    - point Cabal at the Rust build artifacts
 #
-# Prerequisites: run inside the Nix dev shell (provides gcc, cabal, cbindgen, hs-bindgen-cli).
+# System include paths (needed by libclang on NixOS) are detected
+# automatically at TH compile time by GarnetRs.Raw — no env vars needed.
+#
+# Prerequisites: run inside the Nix dev shell (provides gcc, cabal, cbindgen).

 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 RUST_DIR="$SCRIPT_DIR/rust"
-HASKELL_DIR="$SCRIPT_DIR"
 HEADER_NAME="garnet_rs.h"
 HEADER="$RUST_DIR/$HEADER_NAME"

@ -57,36 +58,7 @@ awk '

 echo "  Patched header at $HEADER"

-# --- Step 4: Derive system include paths for hs-bindgen's libclang ---
-#
-# hs-bindgen uses libclang directly, which doesn't know about NixOS's
-# non-standard include locations. We extract them from cpp -v and pass
-# all of them — extra paths are harmless.
-echo "=== Detecting system include paths ==="
-CLANG_OPTIONS=()
-while IFS= read -r dir; do
-  CLANG_OPTIONS+=("--clang-option" "-isystem$dir")
-done < <(echo | cpp -v 2>&1 | awk '/#include <\.\.\.> search starts here:/{f=1;next}/End of search list/{f=0}f{gsub(/^ +/,"");print}')
-
-if [ ${#CLANG_OPTIONS[@]} -eq 0 ]; then
-  echo "  WARNING: No system include paths detected. hs-bindgen may fail."
-else
-  echo "  Found ${#CLANG_OPTIONS[@]} clang options:"
-  for ((i=0; i<${#CLANG_OPTIONS[@]}; i+=2)); do
-    echo "    ${CLANG_OPTIONS[i+1]}"
-  done
-fi
-
-# --- Step 5: Run hs-bindgen ---
-echo "=== Running hs-bindgen ==="
-hs-bindgen-cli preprocess \
-  --overwrite-files --create-output-dirs \
-  --unique-id com.garnet --enable-record-dot \
-  --hs-output-dir "$HASKELL_DIR/generated" --module GarnetRs \
-  "${CLANG_OPTIONS[@]}" \
-  -I "$RUST_DIR" "$HEADER_NAME"
-
-# --- Step 6: Configure Cabal ---
+# --- Step 4: Configure Cabal ---
 #
 # Point Cabal at the Rust static library and C header. This writes
 # cabal.project.local (gitignored) with absolute paths derived from
@ -97,5 +69,4 @@ cabal configure \
  --extra-include-dirs="$RUST_DIR"

 echo "=== Done ==="
-echo "Generated Haskell bindings in $HASKELL_DIR/generated/"
 echo "Run 'cabal run' to test."
--- a/generated/GarnetRs.hs
+++ b/generated/GarnetRs.hs
@ -1,526 +0,0 @@
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE DeriveGeneric #-}
-{-# LANGUAGE DerivingStrategies #-}
-{-# LANGUAGE DerivingVia #-}
-{-# LANGUAGE DuplicateRecordFields #-}
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE MagicHash #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE NoImplicitPrelude #-}
-{-# LANGUAGE PatternSynonyms #-}
-{-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE TypeApplications #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE TypeOperators #-}
-{-# LANGUAGE UnboxedTuples #-}
-{-# LANGUAGE UndecidableInstances #-}
-
-module GarnetRs where
-
-import qualified Data.Array.Byte
-import qualified Data.List.NonEmpty
-import qualified Data.Primitive.Types
-import qualified Data.Proxy
-import qualified Foreign as F
-import qualified Foreign.C as FC
-import qualified GHC.Generics
-import qualified GHC.Ptr as Ptr
-import qualified GHC.Records
-import qualified HsBindgen.Runtime.CEnum
-import qualified HsBindgen.Runtime.HasCField
-import qualified HsBindgen.Runtime.Internal.ByteArray
-import qualified HsBindgen.Runtime.Internal.HasFFIType
-import qualified HsBindgen.Runtime.Internal.SizedByteArray
-import qualified HsBindgen.Runtime.LibC
-import qualified HsBindgen.Runtime.Marshal
-import qualified Text.Read
-import HsBindgen.Runtime.Internal.TypeEquality (TyEq)
-import Prelude ((<*>), (>>), Eq, Int, Ord, Read, Show, pure, showsPrec)
-
-{-| __C declaration:__ @struct T@
-
-    __defined at:__ @garnet_rs.h 6:8@
-
-    __exported by:__ @garnet_rs.h@
-}
-data T = T
-  { a :: FC.CBool
-    {- ^ __C declaration:__ @a@
-
-         __defined at:__ @garnet_rs.h 7:8@
-
-         __exported by:__ @garnet_rs.h@
-    -}
-  , b :: HsBindgen.Runtime.LibC.Word8
-    {- ^ __C declaration:__ @b@
-
-         __defined at:__ @garnet_rs.h 8:11@
-
-         __exported by:__ @garnet_rs.h@
-    -}
-  }
-  deriving stock (GHC.Generics.Generic)
-  deriving stock (Eq, Show)
-
-instance HsBindgen.Runtime.Marshal.StaticSize T where
-
-  staticSizeOf = \_ -> (2 :: Int)
-
-  staticAlignment = \_ -> (1 :: Int)
-
-instance HsBindgen.Runtime.Marshal.ReadRaw T where
-
-  readRaw =
-    \ptr0 ->
-          pure T
-      <*> HsBindgen.Runtime.HasCField.readRaw (Data.Proxy.Proxy @"a") ptr0
-      <*> HsBindgen.Runtime.HasCField.readRaw (Data.Proxy.Proxy @"b") ptr0
-
-instance HsBindgen.Runtime.Marshal.WriteRaw T where
-
-  writeRaw =
-    \ptr0 ->
-      \s1 ->
-        case s1 of
-          T a2 b3 ->
-               HsBindgen.Runtime.HasCField.writeRaw (Data.Proxy.Proxy @"a") ptr0 a2
-            >> HsBindgen.Runtime.HasCField.writeRaw (Data.Proxy.Proxy @"b") ptr0 b3
-
-deriving via HsBindgen.Runtime.Marshal.EquivStorable T instance F.Storable T
-
-instance HsBindgen.Runtime.HasCField.HasCField T "a" where
-
-  type CFieldType T "a" = FC.CBool
-
-  offset# = \_ -> \_ -> 0
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType T) "a")
-         ) => GHC.Records.HasField "a" (Ptr.Ptr T) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"a")
-
-instance HsBindgen.Runtime.HasCField.HasCField T "b" where
-
-  type CFieldType T "b" = HsBindgen.Runtime.LibC.Word8
-
-  offset# = \_ -> \_ -> 1
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType T) "b")
-         ) => GHC.Records.HasField "b" (Ptr.Ptr T) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"b")
-
-{-| __C declaration:__ @enum Shape_Tag@
-
-    __defined at:__ @garnet_rs.h 11:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-newtype Shape_Tag = Shape_Tag
-  { unwrap :: FC.CUInt
-  }
-  deriving stock (GHC.Generics.Generic)
-  deriving stock (Eq, Ord)
-  deriving newtype (HsBindgen.Runtime.Internal.HasFFIType.HasFFIType)
-
-instance HsBindgen.Runtime.Marshal.StaticSize Shape_Tag where
-
-  staticSizeOf = \_ -> (4 :: Int)
-
-  staticAlignment = \_ -> (4 :: Int)
-
-instance HsBindgen.Runtime.Marshal.ReadRaw Shape_Tag where
-
-  readRaw =
-    \ptr0 ->
-          pure Shape_Tag
-      <*> HsBindgen.Runtime.Marshal.readRawByteOff ptr0 (0 :: Int)
-
-instance HsBindgen.Runtime.Marshal.WriteRaw Shape_Tag where
-
-  writeRaw =
-    \ptr0 ->
-      \s1 ->
-        case s1 of
-          Shape_Tag unwrap2 ->
-            HsBindgen.Runtime.Marshal.writeRawByteOff ptr0 (0 :: Int) unwrap2
-
-deriving via HsBindgen.Runtime.Marshal.EquivStorable Shape_Tag instance F.Storable Shape_Tag
-
-deriving via FC.CUInt instance Data.Primitive.Types.Prim Shape_Tag
-
-instance HsBindgen.Runtime.CEnum.CEnum Shape_Tag where
-
-  type CEnumZ Shape_Tag = FC.CUInt
-
-  toCEnum = Shape_Tag
-
-  fromCEnum = GHC.Records.getField @"unwrap"
-
-  declaredValues =
-    \_ ->
-      HsBindgen.Runtime.CEnum.declaredValuesFromList [ (0, Data.List.NonEmpty.singleton "Circle")
-                                                     , (1, Data.List.NonEmpty.singleton "Rectangle")
-                                                     ]
-
-  showsUndeclared =
-    HsBindgen.Runtime.CEnum.showsWrappedUndeclared "Shape_Tag"
-
-  readPrecUndeclared =
-    HsBindgen.Runtime.CEnum.readPrecWrappedUndeclared "Shape_Tag"
-
-  isDeclared = HsBindgen.Runtime.CEnum.seqIsDeclared
-
-  mkDeclared = HsBindgen.Runtime.CEnum.seqMkDeclared
-
-instance HsBindgen.Runtime.CEnum.SequentialCEnum Shape_Tag where
-
-  minDeclaredValue = Circle
-
-  maxDeclaredValue = Rectangle
-
-instance Show Shape_Tag where
-
-  showsPrec = HsBindgen.Runtime.CEnum.shows
-
-instance Read Shape_Tag where
-
-  readPrec = HsBindgen.Runtime.CEnum.readPrec
-
-  readList = Text.Read.readListDefault
-
-  readListPrec = Text.Read.readListPrecDefault
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Shape_Tag) "unwrap")
-         ) => GHC.Records.HasField "unwrap" (Ptr.Ptr Shape_Tag) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"unwrap")
-
-instance HsBindgen.Runtime.HasCField.HasCField Shape_Tag "unwrap" where
-
-  type CFieldType Shape_Tag "unwrap" = FC.CUInt
-
-  offset# = \_ -> \_ -> 0
-
-{-| __C declaration:__ @Circle@
-
-    __defined at:__ @garnet_rs.h 12:3@
-
-    __exported by:__ @garnet_rs.h@
-}
-pattern Circle :: Shape_Tag
-pattern Circle = Shape_Tag 0
-
-{-| __C declaration:__ @Rectangle@
-
-    __defined at:__ @garnet_rs.h 13:3@
-
-    __exported by:__ @garnet_rs.h@
-}
-pattern Rectangle :: Shape_Tag
-pattern Rectangle = Shape_Tag 1
-
-{-| __C declaration:__ @struct Circle_Body@
-
-    __defined at:__ @garnet_rs.h 16:8@
-
-    __exported by:__ @garnet_rs.h@
-}
-data Circle_Body = Circle_Body
-  { radius :: FC.CDouble
-    {- ^ __C declaration:__ @radius@
-
-         __defined at:__ @garnet_rs.h 17:10@
-
-         __exported by:__ @garnet_rs.h@
-    -}
-  }
-  deriving stock (GHC.Generics.Generic)
-  deriving stock (Eq, Show)
-
-instance HsBindgen.Runtime.Marshal.StaticSize Circle_Body where
-
-  staticSizeOf = \_ -> (8 :: Int)
-
-  staticAlignment = \_ -> (8 :: Int)
-
-instance HsBindgen.Runtime.Marshal.ReadRaw Circle_Body where
-
-  readRaw =
-    \ptr0 ->
-          pure Circle_Body
-      <*> HsBindgen.Runtime.HasCField.readRaw (Data.Proxy.Proxy @"radius") ptr0
-
-instance HsBindgen.Runtime.Marshal.WriteRaw Circle_Body where
-
-  writeRaw =
-    \ptr0 ->
-      \s1 ->
-        case s1 of
-          Circle_Body radius2 ->
-            HsBindgen.Runtime.HasCField.writeRaw (Data.Proxy.Proxy @"radius") ptr0 radius2
-
-deriving via HsBindgen.Runtime.Marshal.EquivStorable Circle_Body instance F.Storable Circle_Body
-
-instance HsBindgen.Runtime.HasCField.HasCField Circle_Body "radius" where
-
-  type CFieldType Circle_Body "radius" = FC.CDouble
-
-  offset# = \_ -> \_ -> 0
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Circle_Body) "radius")
-         ) => GHC.Records.HasField "radius" (Ptr.Ptr Circle_Body) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"radius")
-
-{-| __C declaration:__ @struct Rectangle_Body@
-
-    __defined at:__ @garnet_rs.h 20:8@
-
-    __exported by:__ @garnet_rs.h@
-}
-data Rectangle_Body = Rectangle_Body
-  { width :: FC.CDouble
-    {- ^ __C declaration:__ @width@
-
-         __defined at:__ @garnet_rs.h 21:10@
-
-         __exported by:__ @garnet_rs.h@
-    -}
-  , height :: FC.CDouble
-    {- ^ __C declaration:__ @height@
-
-         __defined at:__ @garnet_rs.h 22:10@
-
-         __exported by:__ @garnet_rs.h@
-    -}
-  }
-  deriving stock (GHC.Generics.Generic)
-  deriving stock (Eq, Show)
-
-instance HsBindgen.Runtime.Marshal.StaticSize Rectangle_Body where
-
-  staticSizeOf = \_ -> (16 :: Int)
-
-  staticAlignment = \_ -> (8 :: Int)
-
-instance HsBindgen.Runtime.Marshal.ReadRaw Rectangle_Body where
-
-  readRaw =
-    \ptr0 ->
-          pure Rectangle_Body
-      <*> HsBindgen.Runtime.HasCField.readRaw (Data.Proxy.Proxy @"width") ptr0
-      <*> HsBindgen.Runtime.HasCField.readRaw (Data.Proxy.Proxy @"height") ptr0
-
-instance HsBindgen.Runtime.Marshal.WriteRaw Rectangle_Body where
-
-  writeRaw =
-    \ptr0 ->
-      \s1 ->
-        case s1 of
-          Rectangle_Body width2 height3 ->
-               HsBindgen.Runtime.HasCField.writeRaw (Data.Proxy.Proxy @"width") ptr0 width2
-            >> HsBindgen.Runtime.HasCField.writeRaw (Data.Proxy.Proxy @"height") ptr0 height3
-
-deriving via HsBindgen.Runtime.Marshal.EquivStorable Rectangle_Body instance F.Storable Rectangle_Body
-
-instance HsBindgen.Runtime.HasCField.HasCField Rectangle_Body "width" where
-
-  type CFieldType Rectangle_Body "width" = FC.CDouble
-
-  offset# = \_ -> \_ -> 0
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Rectangle_Body) "width")
-         ) => GHC.Records.HasField "width" (Ptr.Ptr Rectangle_Body) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"width")
-
-instance HsBindgen.Runtime.HasCField.HasCField Rectangle_Body "height" where
-
-  type CFieldType Rectangle_Body "height" = FC.CDouble
-
-  offset# = \_ -> \_ -> 8
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Rectangle_Body) "height")
-         ) => GHC.Records.HasField "height" (Ptr.Ptr Rectangle_Body) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"height")
-
-{-| __C declaration:__ @union \@Shape_body@
-
-    __defined at:__ @garnet_rs.h 27:3@
-
-    __exported by:__ @garnet_rs.h@
-}
-newtype Shape_body = Shape_body
-  { unwrap :: Data.Array.Byte.ByteArray
-  }
-  deriving stock (GHC.Generics.Generic)
-
-deriving via (HsBindgen.Runtime.Internal.SizedByteArray.SizedByteArray 16) 8 instance HsBindgen.Runtime.Marshal.StaticSize Shape_body
-
-deriving via (HsBindgen.Runtime.Internal.SizedByteArray.SizedByteArray 16) 8 instance HsBindgen.Runtime.Marshal.ReadRaw Shape_body
-
-deriving via (HsBindgen.Runtime.Internal.SizedByteArray.SizedByteArray 16) 8 instance HsBindgen.Runtime.Marshal.WriteRaw Shape_body
-
-deriving via HsBindgen.Runtime.Marshal.EquivStorable Shape_body instance F.Storable Shape_body
-
-{-|
-
-  __See:__ 'set_shape_body_circle'
-
-__C declaration:__ @circle@
-
-__defined at:__ @garnet_rs.h 28:24@
-
-__exported by:__ @garnet_rs.h@
-}
-get_shape_body_circle ::
-     Shape_body
-  -> Circle_Body
-get_shape_body_circle =
-  HsBindgen.Runtime.Internal.ByteArray.getUnionPayload
-
-{-|
-
-  __See:__ 'get_shape_body_circle'
-
-}
-set_shape_body_circle ::
-     Circle_Body
-  -> Shape_body
-set_shape_body_circle =
-  HsBindgen.Runtime.Internal.ByteArray.setUnionPayload
-
-{-|
-
-  __See:__ 'set_shape_body_rectangle'
-
-__C declaration:__ @rectangle@
-
-__defined at:__ @garnet_rs.h 29:27@
-
-__exported by:__ @garnet_rs.h@
-}
-get_shape_body_rectangle ::
-     Shape_body
-  -> Rectangle_Body
-get_shape_body_rectangle =
-  HsBindgen.Runtime.Internal.ByteArray.getUnionPayload
-
-{-|
-
-  __See:__ 'get_shape_body_rectangle'
-
-}
-set_shape_body_rectangle ::
-     Rectangle_Body
-  -> Shape_body
-set_shape_body_rectangle =
-  HsBindgen.Runtime.Internal.ByteArray.setUnionPayload
-
-instance HsBindgen.Runtime.HasCField.HasCField Shape_body "circle" where
-
-  type CFieldType Shape_body "circle" = Circle_Body
-
-  offset# = \_ -> \_ -> 0
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Shape_body) "circle")
-         ) => GHC.Records.HasField "circle" (Ptr.Ptr Shape_body) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"circle")
-
-instance HsBindgen.Runtime.HasCField.HasCField Shape_body "rectangle" where
-
-  type CFieldType Shape_body "rectangle" =
-    Rectangle_Body
-
-  offset# = \_ -> \_ -> 0
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Shape_body) "rectangle")
-         ) => GHC.Records.HasField "rectangle" (Ptr.Ptr Shape_body) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"rectangle")
-
-{-| __C declaration:__ @struct Shape@
-
-    __defined at:__ @garnet_rs.h 25:8@
-
-    __exported by:__ @garnet_rs.h@
-}
-data Shape = Shape
-  { tag :: Shape_Tag
-    {- ^ __C declaration:__ @tag@
-
-         __defined at:__ @garnet_rs.h 26:18@
-
-         __exported by:__ @garnet_rs.h@
-    -}
-  , body :: Shape_body
-    {- ^ __C declaration:__ @body@
-
-         __defined at:__ @garnet_rs.h 30:5@
-
-         __exported by:__ @garnet_rs.h@
-    -}
-  }
-  deriving stock (GHC.Generics.Generic)
-
-instance HsBindgen.Runtime.Marshal.StaticSize Shape where
-
-  staticSizeOf = \_ -> (24 :: Int)
-
-  staticAlignment = \_ -> (8 :: Int)
-
-instance HsBindgen.Runtime.Marshal.ReadRaw Shape where
-
-  readRaw =
-    \ptr0 ->
-          pure Shape
-      <*> HsBindgen.Runtime.HasCField.readRaw (Data.Proxy.Proxy @"tag") ptr0
-      <*> HsBindgen.Runtime.HasCField.readRaw (Data.Proxy.Proxy @"body") ptr0
-
-instance HsBindgen.Runtime.Marshal.WriteRaw Shape where
-
-  writeRaw =
-    \ptr0 ->
-      \s1 ->
-        case s1 of
-          Shape tag2 body3 ->
-               HsBindgen.Runtime.HasCField.writeRaw (Data.Proxy.Proxy @"tag") ptr0 tag2
-            >> HsBindgen.Runtime.HasCField.writeRaw (Data.Proxy.Proxy @"body") ptr0 body3
-
-deriving via HsBindgen.Runtime.Marshal.EquivStorable Shape instance F.Storable Shape
-
-instance HsBindgen.Runtime.HasCField.HasCField Shape "tag" where
-
-  type CFieldType Shape "tag" = Shape_Tag
-
-  offset# = \_ -> \_ -> 0
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Shape) "tag")
-         ) => GHC.Records.HasField "tag" (Ptr.Ptr Shape) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"tag")
-
-instance HsBindgen.Runtime.HasCField.HasCField Shape "body" where
-
-  type CFieldType Shape "body" = Shape_body
-
-  offset# = \_ -> \_ -> 8
-
-instance ( TyEq ty ((HsBindgen.Runtime.HasCField.CFieldType Shape) "body")
-         ) => GHC.Records.HasField "body" (Ptr.Ptr Shape) (Ptr.Ptr ty) where
-
-  getField =
-    HsBindgen.Runtime.HasCField.fromPtr (Data.Proxy.Proxy @"body")
--- a/generated/GarnetRs/FunPtr.hs
+++ b/generated/GarnetRs/FunPtr.hs
@ -1,134 +0,0 @@
-{-# LANGUAGE CApiFFI #-}
-{-# LANGUAGE NoImplicitPrelude #-}
-{-# LANGUAGE TemplateHaskell #-}
-{-# OPTIONS_HADDOCK prune #-}
-
-module GarnetRs.FunPtr where
-
-import qualified Foreign.C as FC
-import qualified GHC.IO.Unsafe
-import qualified GHC.Ptr as Ptr
-import qualified HsBindgen.Runtime.Internal.CAPI
-import qualified HsBindgen.Runtime.Internal.HasFFIType
-import qualified HsBindgen.Runtime.LibC
-import qualified HsBindgen.Runtime.PtrConst
-import Data.Void (Void)
-import GarnetRs
-import Prelude (IO)
-
-$(HsBindgen.Runtime.Internal.CAPI.addCSource (HsBindgen.Runtime.Internal.CAPI.unlines
-  [ "#include <garnet_rs.h>"
-  , "/* com_garnet_GarnetRs_get_hello */"
-  , "__attribute__ ((const))"
-  , "void (*hs_bindgen_faf62265b53521d3 (void)) ("
-  , "  char const *arg1"
-  , ")"
-  , "{"
-  , "  return &hello;"
-  , "}"
-  , "/* com_garnet_GarnetRs_get_hello_struct */"
-  , "__attribute__ ((const))"
-  , "void (*hs_bindgen_0f8c37ef19b17a6d (void)) ("
-  , "  struct T arg1"
-  , ")"
-  , "{"
-  , "  return &hello_struct;"
-  , "}"
-  , "/* com_garnet_GarnetRs_get_hello_shape */"
-  , "__attribute__ ((const))"
-  , "void (*hs_bindgen_287ff3ac660f333b (void)) ("
-  , "  struct Shape arg1"
-  , ")"
-  , "{"
-  , "  return &hello_shape;"
-  , "}"
-  , "/* com_garnet_GarnetRs_get_add */"
-  , "__attribute__ ((const))"
-  , "int64_t (*hs_bindgen_bbabdbe61cd1eeb2 (void)) ("
-  , "  int64_t arg1,"
-  , "  int64_t arg2"
-  , ")"
-  , "{"
-  , "  return &add;"
-  , "}"
-  ]))
-
-- __unique:__ @com_garnet_GarnetRs_get_hello@
-foreign import ccall unsafe "hs_bindgen_faf62265b53521d3" hs_bindgen_faf62265b53521d3_base ::
-     IO (Ptr.FunPtr Void)
-
-- __unique:__ @com_garnet_GarnetRs_get_hello@
-hs_bindgen_faf62265b53521d3 :: IO (Ptr.FunPtr ((HsBindgen.Runtime.PtrConst.PtrConst FC.CChar) -> IO ()))
-hs_bindgen_faf62265b53521d3 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_faf62265b53521d3_base
-
-{-# NOINLINE hello #-}
-{-| __C declaration:__ @hello@
-
-    __defined at:__ @garnet_rs.h 33:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello :: Ptr.FunPtr ((HsBindgen.Runtime.PtrConst.PtrConst FC.CChar) -> IO ())
-hello =
-  GHC.IO.Unsafe.unsafePerformIO hs_bindgen_faf62265b53521d3
-
-- __unique:__ @com_garnet_GarnetRs_get_hello_struct@
-foreign import ccall unsafe "hs_bindgen_0f8c37ef19b17a6d" hs_bindgen_0f8c37ef19b17a6d_base ::
-     IO (Ptr.FunPtr Void)
-
-- __unique:__ @com_garnet_GarnetRs_get_hello_struct@
-hs_bindgen_0f8c37ef19b17a6d :: IO (Ptr.FunPtr (T -> IO ()))
-hs_bindgen_0f8c37ef19b17a6d =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_0f8c37ef19b17a6d_base
-
-{-# NOINLINE hello_struct #-}
-{-| __C declaration:__ @hello_struct@
-
-    __defined at:__ @garnet_rs.h 35:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello_struct :: Ptr.FunPtr (T -> IO ())
-hello_struct =
-  GHC.IO.Unsafe.unsafePerformIO hs_bindgen_0f8c37ef19b17a6d
-
-- __unique:__ @com_garnet_GarnetRs_get_hello_shape@
-foreign import ccall unsafe "hs_bindgen_287ff3ac660f333b" hs_bindgen_287ff3ac660f333b_base ::
-     IO (Ptr.FunPtr Void)
-
-- __unique:__ @com_garnet_GarnetRs_get_hello_shape@
-hs_bindgen_287ff3ac660f333b :: IO (Ptr.FunPtr (Shape -> IO ()))
-hs_bindgen_287ff3ac660f333b =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_287ff3ac660f333b_base
-
-{-# NOINLINE hello_shape #-}
-{-| __C declaration:__ @hello_shape@
-
-    __defined at:__ @garnet_rs.h 37:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello_shape :: Ptr.FunPtr (Shape -> IO ())
-hello_shape =
-  GHC.IO.Unsafe.unsafePerformIO hs_bindgen_287ff3ac660f333b
-
-- __unique:__ @com_garnet_GarnetRs_get_add@
-foreign import ccall unsafe "hs_bindgen_bbabdbe61cd1eeb2" hs_bindgen_bbabdbe61cd1eeb2_base ::
-     IO (Ptr.FunPtr Void)
-
-- __unique:__ @com_garnet_GarnetRs_get_add@
-hs_bindgen_bbabdbe61cd1eeb2 :: IO (Ptr.FunPtr (HsBindgen.Runtime.LibC.Int64 -> HsBindgen.Runtime.LibC.Int64 -> IO HsBindgen.Runtime.LibC.Int64))
-hs_bindgen_bbabdbe61cd1eeb2 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_bbabdbe61cd1eeb2_base
-
-{-# NOINLINE add #-}
-{-| __C declaration:__ @add@
-
-    __defined at:__ @garnet_rs.h 39:32@
-
-    __exported by:__ @garnet_rs.h@
-}
-add :: Ptr.FunPtr (HsBindgen.Runtime.LibC.Int64 -> HsBindgen.Runtime.LibC.Int64 -> IO HsBindgen.Runtime.LibC.Int64)
-add =
-  GHC.IO.Unsafe.unsafePerformIO hs_bindgen_bbabdbe61cd1eeb2
--- a/generated/GarnetRs/Safe.hs
+++ b/generated/GarnetRs/Safe.hs
@ -1,155 +0,0 @@
-{-# LANGUAGE CApiFFI #-}
-{-# LANGUAGE NoImplicitPrelude #-}
-{-# LANGUAGE TemplateHaskell #-}
-{-# OPTIONS_HADDOCK prune #-}
-
-module GarnetRs.Safe where
-
-import qualified Foreign as F
-import qualified Foreign.C as FC
-import qualified GHC.Int
-import qualified GHC.Ptr as Ptr
-import qualified HsBindgen.Runtime.Internal.CAPI
-import qualified HsBindgen.Runtime.Internal.HasFFIType
-import qualified HsBindgen.Runtime.LibC
-import qualified HsBindgen.Runtime.PtrConst
-import Data.Void (Void)
-import GarnetRs
-import Prelude (IO)
-
-$(HsBindgen.Runtime.Internal.CAPI.addCSource (HsBindgen.Runtime.Internal.CAPI.unlines
-  [ "#include <garnet_rs.h>"
-  , "void hs_bindgen_433ea2a26af4e593 ("
-  , "  char const *arg1"
-  , ")"
-  , "{"
-  , "  hello(arg1);"
-  , "}"
-  , "void hs_bindgen_51157946af5519c9 ("
-  , "  struct T *arg1"
-  , ")"
-  , "{"
-  , "  hello_struct(*arg1);"
-  , "}"
-  , "void hs_bindgen_7de06f1fd827ca60 ("
-  , "  struct Shape *arg1"
-  , ")"
-  , "{"
-  , "  hello_shape(*arg1);"
-  , "}"
-  , "int64_t hs_bindgen_1c0c71fa74c428a9 ("
-  , "  int64_t arg1,"
-  , "  int64_t arg2"
-  , ")"
-  , "{"
-  , "  return add(arg1, arg2);"
-  , "}"
-  ]))
-
-- __unique:__ @com_garnet_GarnetRs_Safe_hello@
-foreign import ccall safe "hs_bindgen_433ea2a26af4e593" hs_bindgen_433ea2a26af4e593_base ::
-     Ptr.Ptr Void
-  -> IO ()
-
-- __unique:__ @com_garnet_GarnetRs_Safe_hello@
-hs_bindgen_433ea2a26af4e593 ::
-     HsBindgen.Runtime.PtrConst.PtrConst FC.CChar
-  -> IO ()
-hs_bindgen_433ea2a26af4e593 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_433ea2a26af4e593_base
-
-{-| __C declaration:__ @hello@
-
-    __defined at:__ @garnet_rs.h 33:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello ::
-     HsBindgen.Runtime.PtrConst.PtrConst FC.CChar
-     -- ^ __C declaration:__ @c@
-  -> IO ()
-hello = hs_bindgen_433ea2a26af4e593
-
-- __unique:__ @com_garnet_GarnetRs_Safe_hello_struct@
-foreign import ccall safe "hs_bindgen_51157946af5519c9" hs_bindgen_51157946af5519c9_base ::
-     Ptr.Ptr Void
-  -> IO ()
-
-- __unique:__ @com_garnet_GarnetRs_Safe_hello_struct@
-hs_bindgen_51157946af5519c9 ::
-     Ptr.Ptr T
-  -> IO ()
-hs_bindgen_51157946af5519c9 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_51157946af5519c9_base
-
-{-| __C declaration:__ @hello_struct@
-
-    __defined at:__ @garnet_rs.h 35:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello_struct ::
-     T
-     -- ^ __C declaration:__ @t@
-  -> IO ()
-hello_struct =
-  \t0 ->
-    F.with t0 (\t1 -> hs_bindgen_51157946af5519c9 t1)
-
-- __unique:__ @com_garnet_GarnetRs_Safe_hello_shape@
-foreign import ccall safe "hs_bindgen_7de06f1fd827ca60" hs_bindgen_7de06f1fd827ca60_base ::
-     Ptr.Ptr Void
-  -> IO ()
-
-- __unique:__ @com_garnet_GarnetRs_Safe_hello_shape@
-hs_bindgen_7de06f1fd827ca60 ::
-     Ptr.Ptr Shape
-  -> IO ()
-hs_bindgen_7de06f1fd827ca60 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_7de06f1fd827ca60_base
-
-{-| __C declaration:__ @hello_shape@
-
-    __defined at:__ @garnet_rs.h 37:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello_shape ::
-     Shape
-     -- ^ __C declaration:__ @s@
-  -> IO ()
-hello_shape =
-  \s0 ->
-    F.with s0 (\s1 -> hs_bindgen_7de06f1fd827ca60 s1)
-
-- __unique:__ @com_garnet_GarnetRs_Safe_add@
-foreign import ccall safe "hs_bindgen_1c0c71fa74c428a9" hs_bindgen_1c0c71fa74c428a9_base ::
-     GHC.Int.Int64
-  -> GHC.Int.Int64
-  -> GHC.Int.Int64
-
-- __unique:__ @com_garnet_GarnetRs_Safe_add@
-hs_bindgen_1c0c71fa74c428a9 ::
-     HsBindgen.Runtime.LibC.Int64
-  -> HsBindgen.Runtime.LibC.Int64
-  -> HsBindgen.Runtime.LibC.Int64
-hs_bindgen_1c0c71fa74c428a9 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_1c0c71fa74c428a9_base
-
-{-|
-
-  Marked @__attribute((const))__@
-
-__C declaration:__ @add@
-
-__defined at:__ @garnet_rs.h 39:32@
-
-__exported by:__ @garnet_rs.h@
-}
-add ::
-     HsBindgen.Runtime.LibC.Int64
-     -- ^ __C declaration:__ @a@
-  -> HsBindgen.Runtime.LibC.Int64
-     -- ^ __C declaration:__ @b@
-  -> HsBindgen.Runtime.LibC.Int64
-add = hs_bindgen_1c0c71fa74c428a9
--- a/generated/GarnetRs/Unsafe.hs
+++ b/generated/GarnetRs/Unsafe.hs
@ -1,155 +0,0 @@
-{-# LANGUAGE CApiFFI #-}
-{-# LANGUAGE NoImplicitPrelude #-}
-{-# LANGUAGE TemplateHaskell #-}
-{-# OPTIONS_HADDOCK prune #-}
-
-module GarnetRs.Unsafe where
-
-import qualified Foreign as F
-import qualified Foreign.C as FC
-import qualified GHC.Int
-import qualified GHC.Ptr as Ptr
-import qualified HsBindgen.Runtime.Internal.CAPI
-import qualified HsBindgen.Runtime.Internal.HasFFIType
-import qualified HsBindgen.Runtime.LibC
-import qualified HsBindgen.Runtime.PtrConst
-import Data.Void (Void)
-import GarnetRs
-import Prelude (IO)
-
-$(HsBindgen.Runtime.Internal.CAPI.addCSource (HsBindgen.Runtime.Internal.CAPI.unlines
-  [ "#include <garnet_rs.h>"
-  , "void hs_bindgen_2dfe97662a4d6377 ("
-  , "  char const *arg1"
-  , ")"
-  , "{"
-  , "  hello(arg1);"
-  , "}"
-  , "void hs_bindgen_29d823ada2bc7302 ("
-  , "  struct T *arg1"
-  , ")"
-  , "{"
-  , "  hello_struct(*arg1);"
-  , "}"
-  , "void hs_bindgen_b3f40a03f07eaa85 ("
-  , "  struct Shape *arg1"
-  , ")"
-  , "{"
-  , "  hello_shape(*arg1);"
-  , "}"
-  , "int64_t hs_bindgen_20eb651f0a8faf48 ("
-  , "  int64_t arg1,"
-  , "  int64_t arg2"
-  , ")"
-  , "{"
-  , "  return add(arg1, arg2);"
-  , "}"
-  ]))
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_hello@
-foreign import ccall unsafe "hs_bindgen_2dfe97662a4d6377" hs_bindgen_2dfe97662a4d6377_base ::
-     Ptr.Ptr Void
-  -> IO ()
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_hello@
-hs_bindgen_2dfe97662a4d6377 ::
-     HsBindgen.Runtime.PtrConst.PtrConst FC.CChar
-  -> IO ()
-hs_bindgen_2dfe97662a4d6377 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_2dfe97662a4d6377_base
-
-{-| __C declaration:__ @hello@
-
-    __defined at:__ @garnet_rs.h 33:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello ::
-     HsBindgen.Runtime.PtrConst.PtrConst FC.CChar
-     -- ^ __C declaration:__ @c@
-  -> IO ()
-hello = hs_bindgen_2dfe97662a4d6377
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_hello_struct@
-foreign import ccall unsafe "hs_bindgen_29d823ada2bc7302" hs_bindgen_29d823ada2bc7302_base ::
-     Ptr.Ptr Void
-  -> IO ()
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_hello_struct@
-hs_bindgen_29d823ada2bc7302 ::
-     Ptr.Ptr T
-  -> IO ()
-hs_bindgen_29d823ada2bc7302 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_29d823ada2bc7302_base
-
-{-| __C declaration:__ @hello_struct@
-
-    __defined at:__ @garnet_rs.h 35:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello_struct ::
-     T
-     -- ^ __C declaration:__ @t@
-  -> IO ()
-hello_struct =
-  \t0 ->
-    F.with t0 (\t1 -> hs_bindgen_29d823ada2bc7302 t1)
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_hello_shape@
-foreign import ccall unsafe "hs_bindgen_b3f40a03f07eaa85" hs_bindgen_b3f40a03f07eaa85_base ::
-     Ptr.Ptr Void
-  -> IO ()
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_hello_shape@
-hs_bindgen_b3f40a03f07eaa85 ::
-     Ptr.Ptr Shape
-  -> IO ()
-hs_bindgen_b3f40a03f07eaa85 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_b3f40a03f07eaa85_base
-
-{-| __C declaration:__ @hello_shape@
-
-    __defined at:__ @garnet_rs.h 37:6@
-
-    __exported by:__ @garnet_rs.h@
-}
-hello_shape ::
-     Shape
-     -- ^ __C declaration:__ @s@
-  -> IO ()
-hello_shape =
-  \s0 ->
-    F.with s0 (\s1 -> hs_bindgen_b3f40a03f07eaa85 s1)
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_add@
-foreign import ccall unsafe "hs_bindgen_20eb651f0a8faf48" hs_bindgen_20eb651f0a8faf48_base ::
-     GHC.Int.Int64
-  -> GHC.Int.Int64
-  -> GHC.Int.Int64
-
-- __unique:__ @com_garnet_GarnetRs_Unsafe_add@
-hs_bindgen_20eb651f0a8faf48 ::
-     HsBindgen.Runtime.LibC.Int64
-  -> HsBindgen.Runtime.LibC.Int64
-  -> HsBindgen.Runtime.LibC.Int64
-hs_bindgen_20eb651f0a8faf48 =
-  HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_20eb651f0a8faf48_base
-
-{-|
-
-  Marked @__attribute((const))__@
-
-__C declaration:__ @add@
-
-__defined at:__ @garnet_rs.h 39:32@
-
-__exported by:__ @garnet_rs.h@
-}
-add ::
-     HsBindgen.Runtime.LibC.Int64
-     -- ^ __C declaration:__ @a@
-  -> HsBindgen.Runtime.LibC.Int64
-     -- ^ __C declaration:__ @b@
-  -> HsBindgen.Runtime.LibC.Int64
-add = hs_bindgen_20eb651f0a8faf48
--- a/lib/GarnetRs/Raw.hs
+++ b/lib/GarnetRs/Raw.hs
@ -0,0 +1,46 @@
+{-# LANGUAGE CApiFFI #-}
+{-# LANGUAGE DerivingVia #-}
+{-# LANGUAGE FieldSelectors #-}
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UnboxedTuples #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# OPTIONS_GHC -Wno-unused-imports #-}
+
+module GarnetRs.Raw where
+
+-- TODO this causes HLS to panic, and isn't yet supported by Ormolu/Fourmolu
+-- {-# LANGUAGE ExplicitLevelImports #-}
+-- import HsBindgen.Runtime.LibC qualified
+-- import splice Data.List
+-- import splice Data.Tuple.Extra
+-- import splice HsBindgen.TH
+-- import splice Language.Haskell.TH
+-- import splice System.Process
+-- import splice Prelude
+
+import Data.List
+import Data.Text qualified as T
+import Data.Tuple.Extra
+import HsBindgen.Runtime.LibC qualified
+import HsBindgen.TH
+import Language.Haskell.TH
+import System.Process
+
+do
+    systemDirs <- -- TODO bit of a hack
+        map (Dir . T.unpack . T.strip)
+            . concatMap (takeWhile (maybe False ((== ' ') . fst) . T.uncons) . dropWhile T.null . T.lines)
+            . drop 1
+            . T.splitOn "search starts here:"
+            . T.pack
+            . thd3
+            <$> runIO (readProcessWithExitCode "cpp" ["-v"] "")
+    withHsBindgen
+        def
+            { clang = def{extraIncludeDirs = Pkg "rust" : systemDirs}
+            }
+        def
+        $ hashInclude "garnet_rs.h"
--- a/lib/GarnetRs/Wrapped.hs
+++ b/lib/GarnetRs/Wrapped.hs
@ -3,26 +3,31 @@
 module GarnetRs.Wrapped (
    T (..),
    Shape (..),
+    BTree (..),
    hello,
    helloStruct,
    helloShape,
    add,
+    sumTree,
 ) where

+import Control.Monad.Cont
+import Control.Monad.Trans
 import Data.ByteString
+import Data.Function
 import Data.Word
 import Foreign
 import Foreign.C
-import GarnetRs qualified as Raw
-import GarnetRs.Safe qualified as Raw
+import GarnetRs.Raw qualified as Raw
 import HsBindgen.Runtime.PtrConst
+import System.IO.Unsafe

 data T = T
    { a :: Bool
    , b :: Word8
    }
 convertT :: T -> Raw.T
-convertT T{a, b} = Raw.T{a = fromBool a, b}
+convertT T{a, b} = Raw.T{t_a = fromBool a, t_b = b}

 data Shape
    = Circle CDouble
@ -32,6 +37,22 @@ convertShape = \case
    Circle r -> Raw.Shape Raw.Circle $ Raw.set_shape_body_circle $ Raw.Circle_Body r
    Rectangle w h -> Raw.Shape Raw.Rectangle $ Raw.set_shape_body_rectangle $ Raw.Rectangle_Body w h

+data BTree a
+    = Leaf a
+    | Fork (BTree a) (BTree a)
+withBTree :: BTree Int64 -> (Raw.BTreeC -> IO a) -> IO a
+withBTree =
+    runContT . fix \f -> \case
+        Leaf v -> pure $ Raw.BTreeC Raw.Leaf $ Raw.set_bTreeC_body_leaf $ Raw.Leaf_Body v
+        Fork l r -> do
+            lRaw <- f l
+            rRaw <- f r
+            lPtr <- ContT alloca
+            rPtr <- ContT alloca
+            lift $ poke lPtr lRaw >> poke rPtr rRaw
+            pure . Raw.BTreeC Raw.Fork . Raw.set_bTreeC_body_fork $
+                Raw.Fork_Body (unsafeFromPtr lPtr) (unsafeFromPtr rPtr)
+
 hello :: ByteString -> IO ()
 hello s = useAsCString s $ Raw.hello . unsafeFromPtr

@ -43,3 +64,6 @@ helloShape = Raw.hello_shape . convertShape

 add :: Int64 -> Int64 -> Int64
 add = Raw.add
+
+sumTree :: BTree Int64 -> Int64
+sumTree = unsafePerformIO . flip withBTree Raw.sum_tree
--- a/rust/garnet_rs.h
+++ b/rust/garnet_rs.h
@ -30,6 +30,28 @@ struct Shape {
  } body;
 };

+enum BTreeC_Tag {
+  Leaf,
+  Fork,
+};
+
+struct Leaf_Body {
+  int64_t value;
+};
+
+struct Fork_Body {
+  const struct BTreeC *left;
+  const struct BTreeC *right;
+};
+
+struct BTreeC {
+  enum BTreeC_Tag tag;
+  union {
+    struct Leaf_Body leaf;
+    struct Fork_Body fork;
+  } body;
+};
+
 void hello(const char *c);

 void hello_struct(struct T t);
@ -37,3 +59,5 @@ void hello_struct(struct T t);
 void hello_shape(struct Shape s);

 __attribute__((const)) int64_t add(int64_t a, int64_t b);
+
+int64_t sum_tree(struct BTreeC t);
--- a/rust/lib.rs
+++ b/rust/lib.rs
@ -1,6 +1,9 @@
 #![allow(dead_code)]

-use std::ffi::{CStr, c_char};
+use std::{
+    ffi::{CStr, c_char},
+    ops::Add,
+};

 fn say_hello(name: &str) {
    println!("Hello from Rust, {name}!");
@ -17,6 +20,7 @@ struct T {
    a: bool,
    b: u8,
 }
+
 #[unsafe(no_mangle)]
 extern "C" fn hello_struct(t: T) -> () {
    say_hello(&format!("{:?}", t))
@ -39,3 +43,41 @@ extern "C" fn hello_shape(s: Shape) -> () {
 extern "C" fn add(a: i64, b: i64) -> i64 {
    a + b
 }
+
+#[repr(C)]
+enum BTree<A> {
+    Leaf {
+        value: A,
+    },
+    Fork {
+        left: Box<BTree<A>>,
+        right: Box<BTree<A>>,
+    },
+}
+impl<A> BTree<A>
+where
+    A: Add<Output = A> + Copy,
+{
+    fn sum(&self) -> A {
+        match self {
+            BTree::Leaf { value } => *value,
+            BTree::Fork { left, right } => left.sum() + right.sum(),
+        }
+    }
+}
+
+#[repr(C)]
+enum BTreeC {
+    Leaf {
+        value: i64,
+    },
+    Fork {
+        left: *const BTreeC,
+        right: *const BTreeC,
+    },
+}
+
+#[unsafe(no_mangle)]
+extern "C" fn sum_tree(t: BTreeC) -> i64 {
+    (unsafe { std::mem::transmute::<_, &BTree<i64>>(&t) }).sum()
+}
Author	SHA1	Message	Date
George Thomas	96ec5c1cb1	Switch to Template Haskell mode for `hs-bindgen`	2026-02-20 09:08:16 +00:00
George Thomas	20b47594c6	Avoid IO for tree sum	2026-02-19 21:35:35 +00:00
George Thomas	71e4ffaede	Make Rust tree type polymorphic	2026-02-19 21:28:00 +00:00
George Thomas	58005ee261	Refactor to use continuation monad	2026-02-19 21:18:37 +00:00
George Thomas	ca063b1dd6	Rename tree types	2026-02-19 21:11:58 +00:00
George Thomas	261acca8a4	Define nicer Rust tree type and coerce	2026-02-19 21:11:23 +00:00
George Thomas	55a781eeb8	Add tree example	2026-02-19 20:44:04 +00:00
George Thomas	06767e17ea	Add newline for consistency	2026-02-19 19:37:46 +00:00