basic enum example

This is partly with a view to eventually abstracting away much of the boilerplate.

build

@@ -5,6 +5,6 @@ cargo build --manifest-path ./rust/Cargo.toml
 
 BUNDLED_LIB_DIR=$(cabal list-bin . | sed -e 's=x/garnet/build/garnet/garnet=build=g')
 mkdir -p $BUNDLED_LIB_DIR
-ln -sf $(pwd)/rust/target/debug/libgarnet_rs.a $BUNDLED_LIB_DIR
+ln -sf $(pwd)/rust/target/debug/libgarnet_rs.a $BUNDLED_LIB_DIR/libCgarnet_rs.a
 
 cabal build

exe/Main.hs

@@ -1,13 +1,20 @@
 module Main (main) where
 
+import Data.Vector.Storable qualified as V
 import GarnetRs.Wrapped
+import System.IO
 
 main :: IO ()
 main = do
     hello "Haskell"
     helloStruct T{a = True, b = 42}
     helloStruct T{a = False, b = maxBound}
+    helloEnum E1
+    helloEnum E3
     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)))
+    putStrLn $ "Slice sum: " <> show (sumSlice $ V.fromList [0 .. 5])
+    putStrLn "Nothing." >> printOptional Nothing
+    putStr "Something: " >> hFlush stdout >> printOptional (Just 67)

flake.lock

@@ -1,12 +1,95 @@
 {
   "nodes": {
+    "HTTP": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1451647621,
+        "narHash": "sha256-oHIyw3x0iKBexEo49YeUDV1k74ZtyYKGR2gNJXXRxts=",
+        "owner": "phadej",
+        "repo": "HTTP",
+        "rev": "9bc0996d412fef1787449d841277ef663ad9a915",
+        "type": "github"
+      },
+      "original": {
+        "owner": "phadej",
+        "repo": "HTTP",
+        "type": "github"
+      }
+    },
+    "cabal-32": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1603716527,
+        "narHash": "sha256-X0TFfdD4KZpwl0Zr6x+PLxUt/VyKQfX7ylXHdmZIL+w=",
+        "owner": "haskell",
+        "repo": "cabal",
+        "rev": "48bf10787e27364730dd37a42b603cee8d6af7ee",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "3.2",
+        "repo": "cabal",
+        "type": "github"
+      }
+    },
+    "cabal-34": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1645834128,
+        "narHash": "sha256-wG3d+dOt14z8+ydz4SL7pwGfe7SiimxcD/LOuPCV6xM=",
+        "owner": "haskell",
+        "repo": "cabal",
+        "rev": "5ff598c67f53f7c4f48e31d722ba37172230c462",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "3.4",
+        "repo": "cabal",
+        "type": "github"
+      }
+    },
+    "cabal-36": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1669081697,
+        "narHash": "sha256-I5or+V7LZvMxfbYgZATU4awzkicBwwok4mVoje+sGmU=",
+        "owner": "haskell",
+        "repo": "cabal",
+        "rev": "8fd619e33d34924a94e691c5fea2c42f0fc7f144",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "3.6",
+        "repo": "cabal",
+        "type": "github"
+      }
+    },
+    "cardano-shell": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1608537748,
+        "narHash": "sha256-PulY1GfiMgKVnBci3ex4ptk2UNYMXqGjJOxcPy2KYT4=",
+        "owner": "input-output-hk",
+        "repo": "cardano-shell",
+        "rev": "9392c75087cb9a3d453998f4230930dea3a95725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "input-output-hk",
+        "repo": "cardano-shell",
+        "type": "github"
+      }
+    },
     "crane": {
       "locked": {
-        "lastModified": 1771438068,
+        "lastModified": 1774313767,
-        "narHash": "sha256-nGBbXvEZVe/egCPVPFcu89RFtd8Rf6J+4RFoVCFec0A=",
+        "narHash": "sha256-hy0XTQND6avzGEUFrJtYBBpFa/POiiaGBr2vpU6Y9tY=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "b5090e53e9d68c523a4bb9ad42b4737ee6747597",
+        "rev": "3d9df76e29656c679c744968b17fbaf28f0e923d",
         "type": "github"
       },
       "original": {
@@ -15,6 +98,38 @@
         "type": "github"
       }
     },
+    "flake-compat": {
+      "locked": {
+        "lastModified": 1767039857,
+        "narHash": "sha256-vNpUSpF5Nuw8xvDLj2KCwwksIbjua2LZCqhV1LNRDns=",
+        "owner": "NixOS",
+        "repo": "flake-compat",
+        "rev": "5edf11c44bc78a0d334f6334cdaf7d60d732daab",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "flake-compat_2": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1672831974,
+        "narHash": "sha256-z9k3MfslLjWQfnjBtEtJZdq3H7kyi2kQtUThfTgdRk0=",
+        "owner": "input-output-hk",
+        "repo": "flake-compat",
+        "rev": "45f2638735f8cdc40fe302742b79f248d23eb368",
+        "type": "github"
+      },
+      "original": {
+        "owner": "input-output-hk",
+        "ref": "hkm/gitlab-fix",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -33,6 +148,349 @@
         "type": "github"
       }
     },
+    "hackage": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1770685064,
+        "narHash": "sha256-e2G/GFzIdTXosxq+3Z0OXbSUmXy9tDbZZ6wsmfy7Hf8=",
+        "owner": "input-output-hk",
+        "repo": "hackage.nix",
+        "rev": "84628a8e4b5d580766d49d62a5e2e065cbb8604e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "input-output-hk",
+        "repo": "hackage.nix",
+        "type": "github"
+      }
+    },
+    "hackage-for-stackage": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1770683900,
+        "narHash": "sha256-03cshwLY80e5jBUgNBmoFoiH1e3VvhAX+1ME4NVt5g4=",
+        "owner": "input-output-hk",
+        "repo": "hackage.nix",
+        "rev": "c7d9e737cd1e07136982e0df0f9aa12391e2c883",
+        "type": "github"
+      },
+      "original": {
+        "owner": "input-output-hk",
+        "ref": "for-stackage",
+        "repo": "hackage.nix",
+        "type": "github"
+      }
+    },
+    "hackage-internal": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1750307553,
+        "narHash": "sha256-iiafNoeLHwlSLQTyvy8nPe2t6g5AV4PPcpMeH/2/DLs=",
+        "owner": "input-output-hk",
+        "repo": "hackage.nix",
+        "rev": "f7867baa8817fab296528f4a4ec39d1c7c4da4f3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "input-output-hk",
+        "repo": "hackage.nix",
+        "type": "github"
+      }
+    },
+    "haskell-nix": {
+      "inputs": {
+        "HTTP": "HTTP",
+        "cabal-32": "cabal-32",
+        "cabal-34": "cabal-34",
+        "cabal-36": "cabal-36",
+        "cardano-shell": "cardano-shell",
+        "flake-compat": "flake-compat_2",
+        "hackage": "hackage",
+        "hackage-for-stackage": "hackage-for-stackage",
+        "hackage-internal": "hackage-internal",
+        "hls": "hls",
+        "hls-1.10": "hls-1.10",
+        "hls-2.0": "hls-2.0",
+        "hls-2.10": "hls-2.10",
+        "hls-2.11": "hls-2.11",
+        "hls-2.12": "hls-2.12",
+        "hls-2.2": "hls-2.2",
+        "hls-2.3": "hls-2.3",
+        "hls-2.4": "hls-2.4",
+        "hls-2.5": "hls-2.5",
+        "hls-2.6": "hls-2.6",
+        "hls-2.7": "hls-2.7",
+        "hls-2.8": "hls-2.8",
+        "hls-2.9": "hls-2.9",
+        "hpc-coveralls": "hpc-coveralls",
+        "iserv-proxy": "iserv-proxy",
+        "nixpkgs": [
+          "nix-haskell",
+          "haskell-nix",
+          "nixpkgs-unstable"
+        ],
+        "nixpkgs-2305": "nixpkgs-2305",
+        "nixpkgs-2311": "nixpkgs-2311",
+        "nixpkgs-2405": "nixpkgs-2405",
+        "nixpkgs-2411": "nixpkgs-2411",
+        "nixpkgs-2505": "nixpkgs-2505",
+        "nixpkgs-2511": "nixpkgs-2511",
+        "nixpkgs-unstable": "nixpkgs-unstable",
+        "old-ghc-nix": "old-ghc-nix",
+        "stackage": "stackage"
+      },
+      "locked": {
+        "lastModified": 1773942398,
+        "narHash": "sha256-VFUyPaWqXN357StToBRFbOCZAP4n8iCfEh2ZV1dNH88=",
+        "owner": "ymeister",
+        "repo": "haskell.nix",
+        "rev": "9fa7c11202e16c8cd2743deed4d811da1cfb2e51",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ymeister",
+        "repo": "haskell.nix",
+        "rev": "9fa7c11202e16c8cd2743deed4d811da1cfb2e51",
+        "type": "github"
+      }
+    },
+    "hls": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1741604408,
+        "narHash": "sha256-tuq3+Ip70yu89GswZ7DSINBpwRprnWnl6xDYnS4GOsc=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "682d6894c94087da5e566771f25311c47e145359",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-1.10": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1680000865,
+        "narHash": "sha256-rc7iiUAcrHxwRM/s0ErEsSPxOR3u8t7DvFeWlMycWgo=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "b08691db779f7a35ff322b71e72a12f6e3376fd9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "1.10.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.0": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1687698105,
+        "narHash": "sha256-OHXlgRzs/kuJH8q7Sxh507H+0Rb8b7VOiPAjcY9sM1k=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "783905f211ac63edf982dd1889c671653327e441",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.0.0.1",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.10": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1743069404,
+        "narHash": "sha256-q4kDFyJDDeoGqfEtrZRx4iqMVEC2MOzCToWsFY+TOzY=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "2318c61db3a01e03700bd4b05665662929b7fe8b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.10.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.11": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1747306193,
+        "narHash": "sha256-/MmtpF8+FyQlwfKHqHK05BdsxC9LHV70d/FiMM7pzBM=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "46ef4523ea4949f47f6d2752476239f1c6d806fe",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.11.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.12": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1758709460,
+        "narHash": "sha256-xkI8MIIVEVARskfWbGAgP5sHG/lyeKnkm0LIOJ19X5w=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "7d983de4fa7ff54369f6dd31444bdb9869aec83e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.12.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.2": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1693064058,
+        "narHash": "sha256-8DGIyz5GjuCFmohY6Fa79hHA/p1iIqubfJUTGQElbNk=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "b30f4b6cf5822f3112c35d14a0cba51f3fe23b85",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.2.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.3": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1695910642,
+        "narHash": "sha256-tR58doOs3DncFehHwCLczJgntyG/zlsSd7DgDgMPOkI=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "458ccdb55c9ea22cd5d13ec3051aaefb295321be",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.3.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.4": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1699862708,
+        "narHash": "sha256-YHXSkdz53zd0fYGIYOgLt6HrA0eaRJi9mXVqDgmvrjk=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "54507ef7e85fa8e9d0eb9a669832a3287ffccd57",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.4.0.1",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.5": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1701080174,
+        "narHash": "sha256-fyiR9TaHGJIIR0UmcCb73Xv9TJq3ht2ioxQ2mT7kVdc=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "27f8c3d3892e38edaef5bea3870161815c4d014c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.5.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.6": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1705325287,
+        "narHash": "sha256-+P87oLdlPyMw8Mgoul7HMWdEvWP/fNlo8jyNtwME8E8=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "6e0b342fa0327e628610f2711f8c3e4eaaa08b1e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.6.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.7": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1708965829,
+        "narHash": "sha256-LfJ+TBcBFq/XKoiNI7pc4VoHg4WmuzsFxYJ3Fu+Jf+M=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "50322b0a4aefb27adc5ec42f5055aaa8f8e38001",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.7.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.8": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1715153580,
+        "narHash": "sha256-Vi/iUt2pWyUJlo9VrYgTcbRviWE0cFO6rmGi9rmALw0=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "dd1be1beb16700de59e0d6801957290bcf956a0a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.8.0.0",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
+    "hls-2.9": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1719993701,
+        "narHash": "sha256-wy348++MiMm/xwtI9M3vVpqj2qfGgnDcZIGXw8sF1sA=",
+        "owner": "haskell",
+        "repo": "haskell-language-server",
+        "rev": "90319a7e62ab93ab65a95f8f2bcf537e34dae76a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "haskell",
+        "ref": "2.9.0.1",
+        "repo": "haskell-language-server",
+        "type": "github"
+      }
+    },
     "hls-src": {
       "flake": false,
       "locked": {
@@ -50,50 +508,85 @@
         "type": "github"
       }
     },
+    "hpc-coveralls": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1607498076,
+        "narHash": "sha256-8uqsEtivphgZWYeUo5RDUhp6bO9j2vaaProQxHBltQk=",
+        "owner": "sevanspowell",
+        "repo": "hpc-coveralls",
+        "rev": "14df0f7d229f4cd2e79f8eabb1a740097fdfa430",
+        "type": "github"
+      },
+      "original": {
+        "owner": "sevanspowell",
+        "repo": "hpc-coveralls",
+        "type": "github"
+      }
+    },
     "hs-bindgen-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1773399083,
+        "lastModified": 1774599157,
-        "narHash": "sha256-oF6E1/zRZ4iiZs9QjtQMvHnLMfq/W6CXOX44QbDGYXs=",
+        "narHash": "sha256-jgV67xhWzxMwyiyy5RPtu+VQvGTt+FoMXCWJcZ7lczY=",
         "owner": "well-typed",
         "repo": "hs-bindgen",
-        "rev": "6ca94188abd756a1fb4dd8a4037de3fa7dca0765",
+        "rev": "3c4af10590d0d09e825a9735e9a03d7f60914e21",
         "type": "github"
       },
       "original": {
         "owner": "well-typed",
+        "ref": "release-0.1-alpha2",
         "repo": "hs-bindgen",
-        "rev": "6ca94188abd756a1fb4dd8a4037de3fa7dca0765",
+        "type": "github"
+      }
+    },
+    "iserv-proxy": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1770174258,
+        "narHash": "sha256-x6QYupvHZM7rRpVO4AIC5gUWFprFQ59A95FPC7/Owjg=",
+        "owner": "stable-haskell",
+        "repo": "iserv-proxy",
+        "rev": "91ef7ffdeedfb141a4d69dcf9e550abe3e1160c6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "stable-haskell",
+        "ref": "iserv-syms",
+        "repo": "iserv-proxy",
         "type": "github"
       }
     },
     "libclang-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1773221966,
+        "lastModified": 1774600891,
-        "narHash": "sha256-VPG7jKdq2g/Hwf5cPiy4coAvLULxDeA4KHCVkNSSs5w=",
+        "narHash": "sha256-LTAyNMY4Vu0vPeEq2wXB0KWY4kGtqtHTRmADjLdkv78=",
         "owner": "well-typed",
         "repo": "libclang",
-        "rev": "d6e482df49b88375cf3075928a78ee86c2a068d4",
+        "rev": "1054474fae403bfb52c7919680cac03d3d3d4237",
         "type": "github"
       },
       "original": {
         "owner": "well-typed",
         "repo": "libclang",
-        "rev": "d6e482df49b88375cf3075928a78ee86c2a068d4",
         "type": "github"
       }
     },
     "nix-haskell": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "flake-compat": "flake-compat",
+        "haskell-nix": "haskell-nix",
+        "nixpkgs": "nixpkgs",
+        "reflex-platform": "reflex-platform"
       },
       "locked": {
-        "lastModified": 1774311314,
+        "lastModified": 1774408168,
-        "narHash": "sha256-sxoNFlpTaBnnQerzQ2LTByXPpR37M4pHnhZmzq+9440=",
+        "narHash": "sha256-do26Ik50yH8NYSxuhwzBwNKsxIN88GoovwioWPvCpJU=",
         "owner": "reflex-frp",
         "repo": "nix-haskell",
-        "rev": "85d89f1cc2f591ff6be35e1f112c8ee912fba7bb",
+        "rev": "d6a3bb8f96ff35fd0ae2a0d64f40b584c92aa493",
         "type": "github"
       },
       "original": {
@@ -104,16 +597,164 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1773840656,
+        "lastModified": 1769089682,
-        "narHash": "sha256-9tpvMGFteZnd3gRQZFlRCohVpqooygFuy9yjuyRL2C0=",
+        "narHash": "sha256-9yA/LIuAVQq0lXelrZPjLuLVuZdm03p8tfmHhnDIkms=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "9cf7092bdd603554bd8b63c216e8943cf9b12512",
+        "rev": "078d69f03934859a181e81ba987c2bb033eebfc5",
         "type": "github"
       },
       "original": {
-        "id": "nixpkgs",
+        "owner": "NixOS",
-        "type": "indirect"
+        "repo": "nixpkgs",
+        "rev": "078d69f03934859a181e81ba987c2bb033eebfc5",
+        "type": "github"
+      }
+    },
+    "nixpkgs-2305": {
+      "locked": {
+        "lastModified": 1705033721,
+        "narHash": "sha256-K5eJHmL1/kev6WuqyqqbS1cdNnSidIZ3jeqJ7GbrYnQ=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a1982c92d8980a0114372973cbdfe0a307f1bdea",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-23.05-darwin",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-2311": {
+      "locked": {
+        "lastModified": 1719957072,
+        "narHash": "sha256-gvFhEf5nszouwLAkT9nWsDzocUTqLWHuL++dvNjMp9I=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7144d6241f02d171d25fba3edeaf15e0f2592105",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-23.11-darwin",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-2405": {
+      "locked": {
+        "lastModified": 1735564410,
+        "narHash": "sha256-HB/FA0+1gpSs8+/boEavrGJH+Eq08/R2wWNph1sM1Dg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1e7a8f391f1a490460760065fa0630b5520f9cf8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-24.05-darwin",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-2411": {
+      "locked": {
+        "lastModified": 1751290243,
+        "narHash": "sha256-kNf+obkpJZWar7HZymXZbW+Rlk3HTEIMlpc6FCNz0Ds=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "5ab036a8d97cb9476fbe81b09076e6e91d15e1b6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-24.11-darwin",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-2505": {
+      "locked": {
+        "lastModified": 1764560356,
+        "narHash": "sha256-M5aFEFPppI4UhdOxwdmceJ9bDJC4T6C6CzCK1E2FZyo=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6c8f0cca84510cc79e09ea99a299c9bc17d03cb6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-25.05-darwin",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-2511": {
+      "locked": {
+        "lastModified": 1764572236,
+        "narHash": "sha256-hLp6T/vKdrBQolpbN3EhJOKTXZYxJZPzpnoZz+fEGlE=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "b0924ea1889b366de6bb0018a9db70b2c43a15f8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-25.11-darwin",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1764587062,
+        "narHash": "sha256-hdFa0TAVQAQLDF31cEW3enWmBP+b592OvHs6WVe3D8k=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "c1cb7d097cb250f6e1904aacd5f2ba5ffd8a49ce",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "old-ghc-nix": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1631092763,
+        "narHash": "sha256-sIKgO+z7tj4lw3u6oBZxqIhDrzSkvpHtv0Kki+lh9Fg=",
+        "owner": "angerman",
+        "repo": "old-ghc-nix",
+        "rev": "af48a7a7353e418119b6dfe3cd1463a657f342b8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "angerman",
+        "ref": "master",
+        "repo": "old-ghc-nix",
+        "type": "github"
+      }
+    },
+    "reflex-platform": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1760924715,
+        "narHash": "sha256-pUraGts8qa3R9jQqaVXevkC+nM07B8oF+LGF4xsyiJU=",
+        "owner": "reflex-frp",
+        "repo": "reflex-platform",
+        "rev": "4482ecb04c5939ac77c26d769d149dee12051a13",
+        "type": "github"
+      },
+      "original": {
+        "owner": "reflex-frp",
+        "repo": "reflex-platform",
+        "rev": "4482ecb04c5939ac77c26d769d149dee12051a13",
+        "type": "github"
       }
     },
     "root": {
@@ -124,22 +765,25 @@
         "hs-bindgen-src": "hs-bindgen-src",
         "libclang-src": "libclang-src",
         "nix-haskell": "nix-haskell",
+        "nixpkgs": [
+          "nix-haskell",
+          "nixpkgs"
+        ],
         "rust-overlay": "rust-overlay"
       }
     },
     "rust-overlay": {
       "inputs": {
         "nixpkgs": [
-          "nix-haskell",
           "nixpkgs"
         ]
       },
       "locked": {
-        "lastModified": 1771470520,
+        "lastModified": 1774408260,
-        "narHash": "sha256-PvytHcaYN5cPUll7FB70mXv1rRsIBRmu47fFfq3haxA=",
+        "narHash": "sha256-Jn9d9r85dmf3gTMnSRt6t+DP2nQ5uJns/MMXg2FpzfM=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "a1d4cc1f264c45d3745af0d2ca5e59d460e58777",
+        "rev": "d6471ee5a8f470251e6e5b83a20a182eb6c46c9b",
         "type": "github"
       },
       "original": {
@@ -148,6 +792,22 @@
         "type": "github"
       }
     },
+    "stackage": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1770596307,
+        "narHash": "sha256-88b6YzeBaQr9ihSWAOxVGewCDfROKt2rOIHymadu3DI=",
+        "owner": "input-output-hk",
+        "repo": "stackage.nix",
+        "rev": "ff21e9b6a976faed56963ae5fa5d5396dc48ea63",
+        "type": "github"
+      },
+      "original": {
+        "owner": "input-output-hk",
+        "repo": "stackage.nix",
+        "type": "github"
+      }
+    },
     "systems": {
       "locked": {
         "lastModified": 1681028828,

flake.nix

@@ -1,43 +1,107 @@
 {
   inputs = {
     nix-haskell.url = "github:reflex-frp/nix-haskell";
+    nixpkgs.follows = "nix-haskell/nixpkgs";
     hls-src = { url = "github:haskell/haskell-language-server/2.13.0.0"; flake = false; };
-    hs-bindgen-src = { url = "github:well-typed/hs-bindgen/6ca94188abd756a1fb4dd8a4037de3fa7dca0765"; flake = false; };
+    hs-bindgen-src = { url = "github:well-typed/hs-bindgen/release-0.1-alpha2"; flake = false; };
-    libclang-src = { url = "github:well-typed/libclang/d6e482df49b88375cf3075928a78ee86c2a068d4"; flake = false; };
+    libclang-src = { url = "github:well-typed/libclang"; flake = false; };
     flake-utils.url = "github:numtide/flake-utils";
     crane.url = "github:ipetkov/crane";
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
-      inputs.nixpkgs.follows = "nix-haskell/nixpkgs";
+      inputs.nixpkgs.follows = "nixpkgs";
     };
   };
   outputs =
-    inputs@{ nix-haskell, ... }:
+    inputs:
     inputs.flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
     let
-      lib = nix-haskell.lib.${system};
+      pkgs = (import inputs.nixpkgs { inherit system; }).extend (import inputs.rust-overlay);
-      project = lib.nix-haskell (import ./project.nix { inherit (inputs) hls-src hs-bindgen-src libclang-src; });
+      crane = (inputs.crane.mkLib pkgs).overrideToolchain (p: p.rust-bin.selectLatestNightlyWith (
-      haskell = project.haskell-nix.project;
-      pkgs = project.nixpkgs.extend (import inputs.rust-overlay);
-      rust = (inputs.crane.mkLib pkgs).overrideToolchain (p: p.rust-bin.selectLatestNightlyWith (
         toolchain: toolchain.default.override {
-          extensions = [ "rust-src" ];
+          extensions = [ "rust-src" "rust-analyzer" ];
           targets = [ "x86_64-unknown-linux-gnu" ];
         }
       ));
+      addLibcIncludeDir =
+        ''
+          export C_INCLUDE_PATH="${pkgs.stdenv.cc.libc.dev}/include''${C_INCLUDE_PATH:+:$C_INCLUDE_PATH}"
+        '';
+      project = (import inputs.nix-haskell { inherit system inputs; } {
+        name = "garnet";
+        src = ./.;
+        compiler-nix-name = "ghc914";
+        source-repository-packages = {
+          # not on Hackage yet: https://well-typed.com/blog/2026/02/hs-bindgen-alpha
+          # we're using more recent versions than in that post, because we want record-dot support:
+          # https://github.com/well-typed/hs-bindgen/issues/1829#issuecomment-4081875451
+          c-expr-dsl = inputs.hs-bindgen-src + "/c-expr-dsl";
+          c-expr-runtime = inputs.hs-bindgen-src + "/c-expr-runtime";
+          hs-bindgen = inputs.hs-bindgen-src + "/hs-bindgen";
+          hs-bindgen-runtime = inputs.hs-bindgen-src + "/hs-bindgen-runtime";
+          libclang-bindings = inputs.libclang-src;
+        };
+        overrides = [
+          ({ pkgs, ... }: {
+            packages.libclang-bindings.components.library = {
+              build-tools = [ pkgs.llvmPackages.llvm ];
+              libs = [ pkgs.llvmPackages.libclang ];
+            };
+            packages.garnet.components.library = {
+              preBuild = addLibcIncludeDir;
+              preConfigure = ''
+                mkdir -p rust/target/debug
+                ln -s ${garnet-rs}/include/garnet_rs.h rust/target/debug/garnet_rs.h
+              '';
+              preInstall = ''
+                cp ${garnet-rs}/lib/libCgarnet_rs.a dist/build/libCgarnet_rs.a
+              '';
+              configureFlags = [ "--extra-lib-dirs=${garnet-rs}/lib" ];
+            };
+          })
+        ];
+        shell = {
+          tools = {
+            cabal = "latest";
+            haskell-language-server = {
+              src = inputs.hls-src;
+              sha256map = {
+                "https://github.com/snowleopard/alga" = {
+                  "d4e43fb42db05413459fb2df493361d5a666588a" = "0s1mlnl64wj7pkg3iipv5bb4syy3bhxwqzqv93zqlvkyfn64015i";
+                };
+              };
+            };
+          };
+          withHoogle = false;
+          withHaddock = true;
+          shellHook = addLibcIncludeDir;
+        };
+      }).project.haskell-nix;
+      garnet-rs = crane.buildPackage {
+        src = crane.cleanCargoSource ./rust;
+        doCheck = false;
+        installPhaseCommand = ''
+          mkdir -p $out/lib $out/include
+          cp target/release/libgarnet_rs.a $out/lib/libCgarnet_rs.a
+          cp target/release/garnet_rs.h $out/include/
+        '';
+      };
     in
-    {
+    rec {
+      defaultPackage = packages.garnet-exe;
+      packages = let garnet = project.hsPkgs.garnet; in {
+        inherit garnet-rs;
+        garnet-exe = garnet.components.exes.garnet;
+        garnet-lib = garnet.components.library;
+      };
       devShells.default = pkgs.mkShell {
         inputsFrom = [
-          (haskell.shell.overrideAttrs (old: {
+          project.shell
-            shellHook = builtins.replaceStrings [ "*wasm*|)" ] [ "*wasm*)" ] old.shellHook;
+          (crane.devShell { })
-          }))
-          (rust.devShell { })
         ];
         packages = with pkgs; [
           bacon
           ghcid
-          rust-analyzer
         ];
       };
     });

garnet.cabal

@@ -6,6 +6,13 @@ author: Patrick Aldis
 maintainer:
     george.thomas@obsidian.systems
     patrick.aldis@obsidian.systems
+-- aha, nice, this does fix recompilation checking
+extra-source-files:
+    rust/target/debug/garnet_rs.h
+-- that could be problematic given file is gitignored? unfortunately this doesn't work
+-- tbf, I haven't even looked up the docs, just saw the autocompletion
+-- extra-tmp-files:
+--     rust/target/debug/garnet_rs.h
 
 common common
     default-language: GHC2024
@@ -22,17 +29,20 @@ common common
         NoMonomorphismRestriction
         OverloadedRecordDot
         OverloadedStrings
+        PatternSynonyms
         RecordWildCards
         ViewPatterns
     ghc-options:
         -Wall
         -fdefer-type-errors
     build-depends:
+        base,
         bytestring,
         extra,
         mtl,
         process,
         text,
+        vector,
 
 library
     import: common
@@ -41,12 +51,13 @@ library
         GarnetRs.Wrapped
     hs-source-dirs: lib
     include-dirs: rust/target/debug
-    extra-bundled-libraries: garnet_rs
+    -- HLS gives up entirely when the header is malformed if we do this
+    -- and anyway, I don't think it gives us dependency tracking like `extra-source-files` does
+    -- includes: garnet_rs.h
+    extra-bundled-libraries: Cgarnet_rs
     build-depends:
-        base,
         hs-bindgen,
         hs-bindgen-runtime,
-        primitive,
         template-haskell,
 
 executable garnet
@@ -58,5 +69,4 @@ executable garnet
         -rtsopts
         -with-rtsopts=-N
     build-depends:
-        base,
         garnet,

lib/GarnetRs/Raw.hs

@@ -1,6 +1,5 @@
 {-# LANGUAGE CApiFFI #-}
 {-# LANGUAGE DerivingVia #-}
-{-# LANGUAGE FieldSelectors #-}
 {-# LANGUAGE MagicHash #-}
 {-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE TemplateHaskell #-}
@@ -30,19 +29,10 @@ 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/target/debug" : systemDirs}
+        { clang = def{extraIncludeDirs = [Pkg "rust/target/debug"]}
-            , fieldNamingStrategy = EnableRecordDot
+        , fieldNamingStrategy = OmitFieldPrefixes
         }
     def
     $ hashInclude "garnet_rs.h"

lib/GarnetRs/Wrapped.hs

@@ -2,19 +2,29 @@
 -- or look at upstream plans: https://github.com/well-typed/hs-bindgen/issues?q=state%3Aopen%20label%3A%22highlevel%22
 module GarnetRs.Wrapped (
     T (..),
+    Raw.E (..),
+    -- TODO hmm, we don't really want to have to list all of these...
+    -- is there an option to make them not be patterns at all?
+    pattern Raw.E1,
+    pattern Raw.E2,
+    pattern Raw.E3,
     Shape (..),
     BTree (..),
     hello,
     helloStruct,
+    helloEnum,
     helloShape,
     add,
     sumTree,
+    sumSlice,
+    printOptional,
 ) where
 
 import Control.Monad.Cont
 import Control.Monad.Trans
 import Data.ByteString
 import Data.Function
+import Data.Vector.Storable qualified as V
 import Data.Word
 import Foreign
 import Foreign.C
@@ -34,8 +44,8 @@ data Shape
     | Rectangle CDouble CDouble
 convertShape :: Shape -> Raw.Shape
 convertShape = \case
-    Circle r -> Raw.Shape Raw.Circle $ Raw.set_shape_body_circle $ Raw.Circle_Body r
+    Circle r -> Raw.Shape Raw.Circle $ Raw.set_shape_circle_circle $ Raw.Circle_Body r
-    Rectangle w h -> Raw.Shape Raw.Rectangle $ Raw.set_shape_body_rectangle $ Raw.Rectangle_Body w h
+    Rectangle w h -> Raw.Shape Raw.Rectangle $ Raw.set_shape_circle_rectangle $ Raw.Rectangle_Body w h
 
 data BTree a
     = Leaf a
@@ -43,27 +53,38 @@ data 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
+        Leaf v -> pure $ Raw.BTreeC Raw.Leaf $ Raw.set_bTreeC_leaf_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 $
+            pure . Raw.BTreeC Raw.Fork . Raw.set_bTreeC_leaf_fork $
                 Raw.Fork_Body (unsafeFromPtr lPtr) (unsafeFromPtr rPtr)
 
 hello :: ByteString -> IO ()
-hello s = useAsCString s $ Raw.hello . unsafeFromPtr
+hello bs = useAsCString bs \ptr -> Raw.hello $ unsafeFromPtr ptr
 
 helloStruct :: T -> IO ()
-helloStruct = Raw.hello_struct . convertT
+helloStruct t = with (convertT t) \ptr -> Raw.hello_struct $ unsafeFromPtr ptr
+
+helloEnum :: Raw.E -> IO ()
+helloEnum e = with e \ptr -> Raw.hello_enum $ unsafeFromPtr ptr
 
 helloShape :: Shape -> IO ()
-helloShape = Raw.hello_shape . convertShape
+helloShape s = with (convertShape s) \ptr -> Raw.hello_shape $ unsafeFromPtr ptr
 
 add :: Int64 -> Int64 -> Int64
 add = Raw.add
 
 sumTree :: BTree Int64 -> Int64
-sumTree = unsafePerformIO . flip withBTree Raw.sum_tree
+sumTree t = unsafePerformIO $ withBTree t \tc -> with tc \ptr -> Raw.sum_tree $ unsafeFromPtr ptr
+
+sumSlice :: V.Vector Int64 -> Int64
+sumSlice v = unsafePerformIO $ V.unsafeWith v \ptr -> Raw.sum_slice (unsafeFromPtr ptr) (fromIntegral $ V.length v)
+
+printOptional :: Maybe Int8 -> IO ()
+printOptional = \case
+    Nothing -> Raw.print_optional $ unsafeFromPtr nullPtr
+    Just t -> with t \ptr -> Raw.print_optional $ unsafeFromPtr ptr

project.nix

@@ -1,40 +0,0 @@
-{ hls-src
-, hs-bindgen-src
-, libclang-src
-}:
-{
-  name = "garnet";
-  src = ./.;
-  compiler-nix-name = "ghc914";
-  source-repository-packages = {
-    # not on Hackage yet: https://well-typed.com/blog/2026/02/hs-bindgen-alpha
-    # we're using more recent versions than in that post, because we want record-dot support:
-    # https://github.com/well-typed/hs-bindgen/issues/1829#issuecomment-4081875451
-    c-expr-dsl = hs-bindgen-src + "/c-expr-dsl";
-    c-expr-runtime = hs-bindgen-src + "/c-expr-runtime";
-    hs-bindgen = hs-bindgen-src + "/hs-bindgen";
-    hs-bindgen-runtime = hs-bindgen-src + "/hs-bindgen-runtime";
-    libclang-bindings = libclang-src;
-  };
-  overrides = [
-    ({ pkgs, ... }: {
-      packages.libclang-bindings.components.library = {
-        build-tools = [ pkgs.llvmPackages.llvm ];
-        libs = [ pkgs.llvmPackages.libclang ];
-      };
-    })
-  ];
-  shell = {
-    tools = {
-      cabal = "latest";
-      haskell-language-server = {
-        src = hls-src;
-        sha256map = {
-          "https://github.com/snowleopard/alga"."d4e43fb42db05413459fb2df493361d5a666588a" = "0s1mlnl64wj7pkg3iipv5bb4syy3bhxwqzqv93zqlvkyfn64015i";
-        };
-      };
-    };
-    withHoogle = false;
-    withHaddock = true;
-  };
-}

rust/build.rs

@@ -1,43 +1,36 @@
 use std::env;
-use std::fs;
 use std::path::PathBuf;
 
 fn main() {
+    // this doesn't make _much_ difference really, since this is our only Rust source file
+    // but it seems it's probably better than not having it
+    // what we really want is to tell Rust to only regenerate the header file if the Rust code actually compiles
+    // but we don't have that flexibility
+    // and it's an issue because cbindgen tries to be fault-tolerant in some ways that don't even seem to make sense
+    //
+    // e.g. mis-spell "Option" as "Option" and you get
+    // void print_optional(Optio<const int8_t*> x);
+    // instead of
+    // void print_optional(const int8_t *x);
+    // and that's only an issue because in HLS TH dependent-file watching gives up after an error
+    // i.e. once the containing splice has thrown an exception once, the containing file needs a manual edit to kick it
+    // and that's really not helped by Rust Analyzer mostly only showing diagnostics on save
+    // P.S. strings to stdout?! what a terrible API
+    // don't get me started in the discoverability of actually then using the terminal for debugging:
+    // println!("cargo::warning={:?}", env::var("OUT_DIR"));
+    println!("cargo::rerun-if-changed=lib.rs");
     let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
     let profile = env::var("PROFILE").unwrap();
-
+    cbindgen::Builder::new()
-    let bindings = cbindgen::Builder::new()
         .with_crate(&crate_dir)
         .with_language(cbindgen::Language::C)
         .with_style(cbindgen::Style::Tag)
         .generate()
-        .expect("Unable to generate bindings");
+        .expect("Unable to generate bindings")
-
+        .write_to_file(
-    // TODO vibe-coded workaround for hs-bindgen issue:
-    // https://github.com/well-typed/hs-bindgen/issues/1649#issuecomment-3994425922
-    let mut buf = Vec::new();
-    bindings.write(&mut buf);
-    let header = String::from_utf8(buf).unwrap();
-    let mut patched = String::new();
-    let mut saw_union = false;
-    for line in header.lines() {
-        if line == "  };" && saw_union {
-            patched.push_str("  } body;\n");
-            saw_union = false;
-            continue;
-        }
-        if line == "  union {" {
-            saw_union = true;
-        }
-        patched.push_str(line);
-        patched.push('\n');
-    }
-    fs::write(
             PathBuf::from(&crate_dir)
                 .join("target")
                 .join(&profile)
                 .join("garnet_rs.h"),
-        patched,
+        );
-    )
-    .unwrap();
 }

rust/lib.rs

@@ -3,6 +3,7 @@
 use std::{
     ffi::{CStr, c_char},
     ops::Add,
+    slice,
 };
 
 fn say_hello(name: &str) {
@@ -10,7 +11,7 @@ fn say_hello(name: &str) {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello(c: *const c_char) -> () {
+extern "C" fn hello(c: *const c_char) {
     say_hello(unsafe { CStr::from_ptr(c) }.to_str().unwrap())
 }
 
@@ -22,10 +23,23 @@ struct T {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello_struct(t: T) -> () {
+extern "C" fn hello_struct(t: &T) {
     say_hello(&format!("{:?}", t))
 }
 
+#[repr(C)]
+#[derive(Debug)]
+enum E {
+    E1,
+    E2,
+    E3,
+}
+
+#[unsafe(no_mangle)]
+extern "C" fn hello_enum(e: &E) {
+    say_hello(&format!("{:?}", e))
+}
+
 #[repr(C)]
 #[derive(Debug)]
 enum Shape {
@@ -34,7 +48,7 @@ enum Shape {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello_shape(s: Shape) -> () {
+extern "C" fn hello_shape(s: &Shape) {
     say_hello(&format!("{:?}", s))
 }
 
@@ -78,6 +92,19 @@ enum BTreeC {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn sum_tree(t: BTreeC) -> i64 {
+extern "C" fn sum_tree(t: &BTreeC) -> i64 {
-    (unsafe { std::mem::transmute::<_, &BTree<i64>>(&t) }).sum()
+    (unsafe { std::mem::transmute::<_, &BTree<i64>>(t) }).sum()
+}
+
+#[unsafe(no_mangle)]
+extern "C" fn sum_slice(v: *const i64, s: usize) -> i64 {
+    unsafe { slice::from_raw_parts(v, s) }.iter().sum()
+}
+
+#[unsafe(no_mangle)]
+extern "C" fn print_optional(x: Option<&i8>) -> () {
+    match x {
+        Some(x) => println!("{}", x / 2),
+        None => {}
+    }
 }