Add a 'dir' function

example.js

 function (args) {
   var env = args.environ;
-  var argv = args.argv
-  return argv
-  var result = Object.keys(env);
+  var argv = args.argv;
+  var modules = args.modules;
+  var result = modules.dir('./src');
   print(JSON.stringify(result));
   return result
 }

src/app_push_dir.c

+#include <dirent.h>
+#include <stdio.h>
+
+int app_push_dir (duk_context *ctx) {
+  // Check argument
+  const char *dirname = duk_require_string(ctx, -1);
+
+  // Construct array
+  duk_idx_t dir_idx = duk_push_array(ctx);
+
+  // Shove filenames into array
+  struct dirent *dir;
+  int i = 0;
+  DIR *d = opendir(dirname);
+  if (d) {
+    while (i < 100) {
+      dir = readdir(d);
+      if (dir == NULL) break;
+      duk_push_string(ctx, dir->d_name);
+      duk_put_prop_index(ctx, dir_idx, i);
+      i++;
+    }
+    closedir(d);
+  }
+  return 1;
+}

src/main.c

@@ -13,6 +13,7 @@
 
 #include "app_push_argv.c"
 #include "app_push_environ.c"
+#include "app_push_dir.c"
 #include "native_print.c"
 #include "native_adder.c"
 #include "native_import.c"
@@ -53,7 +54,13 @@ int main(int argc, char *argv[] /* char *environ[] */) {
   // Create environment variables object
   ret = app_push_environ(ctx);
   duk_put_prop_string(ctx, argument_idx, "environ");
+  // Provide access to native functions
+  ret = duk_push_object(ctx);
+  duk_push_c_function(ctx, app_push_dir, 1);
+  duk_put_prop_string(ctx, ret, "dir");
+  duk_put_prop_string(ctx, argument_idx, "modules");
 
+  // Run top-level module
   ret = duk_pcall(ctx, 1);
   if (ret != 0) {
     fprintf(stderr, "%s %s\n", argv[1], duk_safe_to_string(ctx, -1));