Add vector/slice example

exe/Main.hs

@@ -1,5 +1,6 @@
 module Main (main) where
 
+import Data.Vector.Storable qualified as V
 import GarnetRs.Wrapped
 
 main :: IO ()
@@ -11,3 +12,4 @@ main = do
     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])

garnet.cabal

@@ -34,6 +34,7 @@ common common
         mtl,
         process,
         text,
+        vector,
 
 library
     import: common

lib/GarnetRs/Wrapped.hs

@@ -9,12 +9,14 @@ module GarnetRs.Wrapped (
     helloShape,
     add,
     sumTree,
+    sumSlice,
 ) 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
@@ -67,3 +69,6 @@ add = Raw.add
 
 sumTree :: BTree Int64 -> Int64
 sumTree = unsafePerformIO . flip withBTree (flip with $ Raw.sum_tree . unsafeFromPtr)
+
+sumSlice :: V.Vector Int64 -> Int64
+sumSlice v = unsafePerformIO $ V.unsafeWith v \p -> Raw.sum_slice (unsafeFromPtr p) (fromIntegral $ V.length v)

rust/lib.rs

@@ -3,6 +3,7 @@
 use std::{
     ffi::{CStr, c_char},
     ops::Add,
+    slice,
 };
 
 fn say_hello(name: &str) {
@@ -81,3 +82,8 @@ enum BTreeC {
 extern "C" fn sum_tree(t: &BTreeC) -> i64 {
     (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()
+}