Create manual high level wrapper

haskell/exe/GarnetRs/Wrapped.hs

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

haskell/exe/Main.hs

@@ -1,14 +1,10 @@
 module Main (main) where
 
-import Data.ByteString
-import Foreign.C
-import GarnetRs
-import GarnetRs.Safe
-import HsBindgen.Runtime.PtrConst
+import GarnetRs.Wrapped
 
 main :: IO ()
 main = do
-    useAsCString "Haskell" $ hello . unsafeFromPtr
-    hello_struct T{a = CBool 1, b = 42}
-    hello_shape $ Shape (Shape_Tag 0) $ set_shape_body_circle $ Circle_Body 3.14
-    hello_shape $ Shape (Shape_Tag 1) $ set_shape_body_rectangle $ Rectangle_Body 10.0 5.0
+    hello "Haskell"
+    helloStruct T{a = True, b = 42}
+    helloShape $ Circle 3.14
+    helloShape $ Rectangle 10.0 5.0

haskell/garnet.cabal

@@ -23,6 +23,8 @@ library garnet-generated
 
 executable garnet
     main-is: Main.hs
+    other-modules:
+        GarnetRs.Wrapped
     hs-source-dirs: exe
     default-language: GHC2024
     default-extensions: