refactor

Seeing as we now no longer need to modify generated header files.

flake.nix

@@ -13,70 +13,20 @@
     };
   };
   outputs =
-    inputs:
+    inputs@{ nix-haskell, ... }:
     inputs.flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
     let
       pkgs = (import inputs.nixpkgs { inherit system; }).extend (import inputs.rust-overlay);
+      nix-haskell = import inputs.nix-haskell { inherit system inputs; };
       crane = (inputs.crane.mkLib pkgs).overrideToolchain (p: p.rust-bin.selectLatestNightlyWith (
         toolchain: toolchain.default.override {
-          extensions = [ "rust-src" "rust-analyzer" ];
+          extensions = [ "rust-src" ];
           targets = [ "x86_64-unknown-linux-gnu" ];
         }
       ));
-      addLibcIncludeDir =
+      project =
-        ''
+        (nix-haskell (import ./project.nix { inherit (inputs) hls-src hs-bindgen-src libclang-src; inherit garnet-rs; })
-          export C_INCLUDE_PATH="${pkgs.stdenv.cc.libc.dev}/include''${C_INCLUDE_PATH:+:$C_INCLUDE_PATH}"
+        ).project.haskell-nix;
-        '';
-      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;
@@ -102,6 +52,7 @@
         packages = with pkgs; [
           bacon
           ghcid
+          rust-analyzer
         ];
       };
     });

garnet.cabal

@@ -29,7 +29,6 @@ common common
         NoMonomorphismRestriction
         OverloadedRecordDot
         OverloadedStrings
-        PatternSynonyms
         RecordWildCards
         ViewPatterns
     ghc-options:

lib/GarnetRs/Raw.hs

@@ -29,10 +29,19 @@ import HsBindgen.TH
 import Language.Haskell.TH
 import System.Process
 
-withHsBindgen
+do
-    def
+    systemDirs <- -- TODO bit of a hack
-        { clang = def{extraIncludeDirs = [Pkg "rust/target/debug"]}
+        map (Dir . T.unpack . T.strip)
-        , fieldNamingStrategy = OmitFieldPrefixes
+            . concatMap (takeWhile (maybe False ((== ' ') . fst) . T.uncons) . dropWhile T.null . T.lines)
-        }
+            . drop 1
-    def
+            . T.splitOn "search starts here:"
-    $ hashInclude "garnet_rs.h"
+            . T.pack
+            . thd3
+            <$> runIO (readProcessWithExitCode "cpp" ["-v"] "")
+    withHsBindgen
+        def
+            { clang = def{extraIncludeDirs = Pkg "rust/target/debug" : systemDirs}
+            , fieldNamingStrategy = OmitFieldPrefixes
+            }
+        def
+        $ hashInclude "garnet_rs.h"

lib/GarnetRs/Wrapped.hs

@@ -1,3 +1,5 @@
+{-# LANGUAGE PatternSynonyms #-}
+
 -- 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 (
@@ -64,27 +66,27 @@ withBTree =
                 Raw.Fork_Body (unsafeFromPtr lPtr) (unsafeFromPtr rPtr)
 
 hello :: ByteString -> IO ()
-hello bs = useAsCString bs \ptr -> Raw.hello $ unsafeFromPtr ptr
+hello = flip useAsCString $ Raw.hello . unsafeFromPtr
 
 helloStruct :: T -> IO ()
-helloStruct t = with (convertT t) \ptr -> Raw.hello_struct $ unsafeFromPtr ptr
+helloStruct = flip with (Raw.hello_struct . unsafeFromPtr) . convertT
 
 helloEnum :: Raw.E -> IO ()
-helloEnum e = with e \ptr -> Raw.hello_enum $ unsafeFromPtr ptr
+helloEnum = flip with (Raw.hello_enum . unsafeFromPtr)
 
 helloShape :: Shape -> IO ()
-helloShape s = with (convertShape s) \ptr -> Raw.hello_shape $ unsafeFromPtr ptr
+helloShape = flip with (Raw.hello_shape . unsafeFromPtr) . convertShape
 
 add :: Int64 -> Int64 -> Int64
 add = Raw.add
 
 sumTree :: BTree Int64 -> Int64
-sumTree t = unsafePerformIO $ withBTree t \tc -> with tc \ptr -> Raw.sum_tree $ unsafeFromPtr ptr
+sumTree = unsafePerformIO . flip withBTree (flip with $ Raw.sum_tree . unsafeFromPtr)
 
 sumSlice :: V.Vector Int64 -> Int64
-sumSlice v = unsafePerformIO $ V.unsafeWith v \ptr -> Raw.sum_slice (unsafeFromPtr ptr) (fromIntegral $ V.length v)
+sumSlice v = unsafePerformIO $ V.unsafeWith v \p -> Raw.sum_slice (unsafeFromPtr p) (fromIntegral $ V.length v)
 
 printOptional :: Maybe Int8 -> IO ()
 printOptional = \case
-    Nothing -> Raw.print_optional $ unsafeFromPtr nullPtr
+    Nothing -> Raw.print_optional (unsafeFromPtr nullPtr)
-    Just t -> with t \ptr -> Raw.print_optional $ unsafeFromPtr ptr
+    Just t -> with t (Raw.print_optional . unsafeFromPtr)

project.nix

@@ -0,0 +1,54 @@
+{ hls-src
+, hs-bindgen-src
+, libclang-src
+, garnet-rs
+}:
+{
+  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 ];
+      };
+    })
+    (_: {
+      packages.garnet.components.library = {
+        preConfigure = ''
+          mkdir -p rust/target/debug
+          ln -s ${garnet-rs}/include/garnet_rs.h rust/target/debug/garnet_rs.h
+          ln -s ${garnet-rs}/lib/libCgarnet_rs.a rust/target/debug/libCgarnet_rs.a
+        '';
+        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 = hls-src;
+        sha256map = {
+          "https://github.com/snowleopard/alga"."d4e43fb42db05413459fb2df493361d5a666588a" = "0s1mlnl64wj7pkg3iipv5bb4syy3bhxwqzqv93zqlvkyfn64015i";
+        };
+      };
+    };
+    withHoogle = false;
+    withHaddock = true;
+  };
+}

rust/lib.rs

@@ -11,7 +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())
 }
 
@@ -23,7 +23,7 @@ struct T {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello_struct(t: &T) {
+extern "C" fn hello_struct(t: &T) -> () {
     say_hello(&format!("{:?}", t))
 }
 
@@ -48,7 +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))
 }