3 files changed, 40 insertions, 0 deletions
diff --git a/ffi/Foo.hs b/ffi/Foo.hs
new file mode 100644
index 0000000..286a8bf
--- /dev/null
+++ b/ffi/Foo.hs
@@ -0,0 +1,10 @@
+module Foo where
+
+foreign export ccall foo :: Int -> IO Int
+
+foo :: Int -> IO Int
+foo n = return (length (f n))
+
+f :: Int -> [Int]
+f 0 = []
+f n = n:(f (n-1))
diff --git a/ffi/Makefile b/ffi/Makefile
new file mode 100644
index 0000000..6f098a6
--- /dev/null
+++ b/ffi/Makefile
@@ -0,0 +1,9 @@
+hask_from_c: Foo.hs foomain.c
+	stack ghc -- Foo.hs
+	stack ghc -- -no-hs-main Foo.o foomain.c -o hask_from_c
+
+clean:
+	- rm *.o
+	- rm *.hi
+	- rm Foo_stub.h
+	- rm hask_from_c
diff --git a/ffi/foomain.c b/ffi/foomain.c
new file mode 100644
index 0000000..70d891c
--- /dev/null
+++ b/ffi/foomain.c
@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include "HsFFI.h"
+
+#ifdef __GLASGOW_HASKELL__
+#include "Foo_stub.h"
+#endif
+
+int main(int argc, char *argv[])
+{
+  int i;
+
+  hs_init(&argc, &argv);
+
+  for (i = 0; i < 5; i++) {
+    printf("%d\n", foo(2500+i));
+    printf("%d\n", foo(2500+i));
+  }
+
+  hs_exit();
+  return 0;
+}