4 files changed, 97 insertions, 0 deletions
diff --git a/src/Lib.hs b/src/Lib.hs
new file mode 100644
index 0000000..d36ff27
--- /dev/null
+++ b/src/Lib.hs
@@ -0,0 +1,6 @@
+module Lib
+    ( someFunc
+    ) where
+
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"
diff --git a/src/Main.hs b/src/Main.hs
new file mode 100644
index 0000000..c43ef13
--- /dev/null
+++ b/src/Main.hs
@@ -0,0 +1,14 @@
+module Main (main) where
+import Control.Monad.Writer (execWriter, MonadWriter (tell))
+
+foreign export ccall call_in :: IO ()
+call_in :: IO ()
+call_in = putStrLn $ execWriter $ do
+  tell "Yo,"
+  tell " This was "
+  tell "Called"
+  tell " From"
+  tell " C!!"
+
+main :: IO ()
+main = putStrLn "This should be dynamically linked!\n"
diff --git a/src/harness/main.c b/src/harness/main.c
new file mode 100644
index 0000000..6666e5e
--- /dev/null
+++ b/src/harness/main.c
@@ -0,0 +1,65 @@
+#include <stdio.h>
+
+#include <dlfcn.h>
+
+typedef void* dllib_t;
+
+dllib_t open_library(const char* library, int* err)
+{
+  dllib_t lib = dlopen(library, RTLD_LAZY);
+
+  if (!lib) {
+    fprintf(stderr, "Error opening shared library: %s\n", dlerror());
+    *err = 1;
+  }
+  *err = 0;
+  return lib;
+}
+
+void* getsym(dllib_t handle, char* sym, int* err)
+{
+  void* ret = dlsym(handle, sym);
+  if (!ret) {
+    fprintf(stderr, "Unable to read symbol '%s'\n", sym);
+    *err |= 1;
+    return NULL;
+  }
+  return ret;
+}
+
+void use_library(int argc, char** argv, dllib_t lib, int* err)
+{
+  *err = 0;
+
+  void (*init)(int* argc, char*** argv) = getsym(lib, "plugin_init", err);
+  void (*teardown)() = getsym(lib, "plugin_teardown", err);
+  void (*sym)() = getsym(lib, "call_in", err);
+
+  if (!sym) {
+    *err = 1;
+    fprintf(stderr, "Unable to find symbol call_in.\n");
+    return;
+  }
+
+  init(&argc, &argv);
+  sym();
+  teardown();
+}
+
+int main(int argc, char** argv)
+{
+  if (!argv[0] && !argv[1]) {
+    fprintf(stderr, "Missing argument.\n");
+    return 1;
+  }
+
+  int err = 0;
+  dllib_t lib = open_library(argv[1], &err);
+
+  if (err) {
+    return err;
+  }
+
+  use_library(argc, argv, lib, &err);
+  return 0;
+}
diff --git a/src/harness_adapter.c b/src/harness_adapter.c
new file mode 100644
index 0000000..9cd8118
--- /dev/null
+++ b/src/harness_adapter.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include "HsFFI.h"
+
+void plugin_init(int* argc, char*** argv)
+{
+  hs_init(argc, argv);
+}
+
+void plugin_teardown()
+{
+  hs_exit();
+}