diff --git a/README.mbt.md b/README.mbt.md
index dd25286..dd7b9c3 100644
--- a/README.mbt.md
+++ b/README.mbt.md
@@ -74,7 +74,7 @@ test "copy text between files" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   @miniio.write_text_file(dir + "/input.txt", "hello\n")
   @miniio.copy_file(dir + "/input.txt", dir + "/output.txt")
@@ -92,7 +92,7 @@ test "append log file" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/tool.log"
   @miniio.write_text_file(path, "start\n")
@@ -111,7 +111,7 @@ test "read and write json" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/manifest.json"
   @miniio.write_json_file(path, { "name": "miniio", "portable": true })
diff --git a/example/cli_tools/moon.mod b/example/cli_tools/moon.mod
new file mode 100644
index 0000000..4020363
--- /dev/null
+++ b/example/cli_tools/moon.mod
@@ -0,0 +1,9 @@
+name = "moonbit-community/miniio-example-cli-tools"
+
+version = "0.1.0"
+
+import {
+  "moonbit-community/miniio@0.2.0",
+}
+
+preferred_target = "wasm"
diff --git a/example/cli_tools/moon.mod.json b/example/cli_tools/moon.mod.json
deleted file mode 100644
index 6a79c15..0000000
--- a/example/cli_tools/moon.mod.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "name": "moonbit-community/miniio-example-cli-tools",
-  "version": "0.1.0",
-  "deps": {
-    "moonbit-community/miniio": "0.1.0"
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/lottie_manifest/moon.mod b/example/lottie_manifest/moon.mod
new file mode 100644
index 0000000..ebf3837
--- /dev/null
+++ b/example/lottie_manifest/moon.mod
@@ -0,0 +1,10 @@
+name = "moonbit-community/miniio-example-lottie-manifest"
+
+version = "0.1.0"
+
+import {
+  "moonbit-community/miniio@0.2.0",
+  "cg-zhou/moon_lottie@0.3.0",
+}
+
+preferred_target = "wasm"
diff --git a/example/lottie_manifest/moon.mod.json b/example/lottie_manifest/moon.mod.json
deleted file mode 100644
index f44529d..0000000
--- a/example/lottie_manifest/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "moonbit-community/miniio-example-lottie-manifest",
-  "version": "0.1.0",
-  "deps": {
-    "moonbit-community/miniio": "0.1.0",
-    "cg-zhou/moon_lottie": "0.3.0"
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/lottie_manifest/moon.pkg b/example/lottie_manifest/moon.pkg
index 99dd1c4..3833934 100644
--- a/example/lottie_manifest/moon.pkg
+++ b/example/lottie_manifest/moon.pkg
@@ -1,6 +1,6 @@
 import {
   "moonbit-community/miniio",
-  "cg-zhou/moon_lottie/lib/parser" @parser,
+  "cg-zhou/moon_lottie/lib/parser",
   "moonbitlang/core/json",
 }
 
diff --git a/example/morm_query/moon.mod b/example/morm_query/moon.mod
new file mode 100644
index 0000000..48cb209
--- /dev/null
+++ b/example/morm_query/moon.mod
@@ -0,0 +1,10 @@
+name = "moonbit-community/miniio-example-morm-query"
+
+version = "0.1.0"
+
+import {
+  "moonbit-community/miniio@0.2.0",
+  "oboard/morm@0.3.15",
+}
+
+preferred_target = "wasm"
diff --git a/example/morm_query/moon.mod.json b/example/morm_query/moon.mod.json
deleted file mode 100644
index 8da2f1d..0000000
--- a/example/morm_query/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "moonbit-community/miniio-example-morm-query",
-  "version": "0.1.0",
-  "deps": {
-    "moonbit-community/miniio": "0.1.0",
-    "oboard/morm": "0.3.12"
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/morm_query/moon.pkg b/example/morm_query/moon.pkg
index b77b6b5..8d0b3c3 100644
--- a/example/morm_query/moon.pkg
+++ b/example/morm_query/moon.pkg
@@ -1,7 +1,7 @@
 import {
   "moonbit-community/miniio",
   "oboard/morm",
-  "oboard/morm/engine" @engine,
+  "oboard/morm/engine",
 }
 
 supported_targets = "wasm"
diff --git a/fd.mbt b/fd.mbt
index 2a7ee29..900d0e5 100644
--- a/fd.mbt
+++ b/fd.mbt
@@ -42,16 +42,16 @@ pub fn File::tell(self : File) -> UInt64 raise Errno {
 }
 
 ///|
-pub impl @io.Reader for File with _get_internal_buffer(self) {
+pub impl @io.Reader for File with fn _get_internal_buffer(self) {
   self.read_buf
 }
 
 ///|
-pub impl @io.Reader for File with _direct_read(self, buf, offset~, max_len~) {
+pub impl @io.Reader for File with fn _direct_read(self, buf, offset~, max_len~) {
   wrap(() => self.raw.read(buf, offset~, max_len~))
 }
 
 ///|
-pub impl @io.Writer for File with write_once(self, data) {
+pub impl @io.Writer for File with fn write_once(self, data) {
   wrap(() => self.raw.write_once(data))
 }
diff --git a/fs.mbt b/fs.mbt
index 3b4189b..c9541ff 100644
--- a/fs.mbt
+++ b/fs.mbt
@@ -38,14 +38,21 @@ pub fn open(
   mode? : Mode = ReadOnly,
   append? : Bool = false,
   create_mode? : CreateMode = OpenExisting,
+  follow_symlink? : Bool = true,
 ) -> File raise Errno {
   {
     raw: wrap(() => {
+      let lookup_flags = if follow_symlink {
+        @raw.LookupFlags::new().symlink_follow()
+      } else {
+        @raw.LookupFlags::new()
+      }
       @raw.open(
         path,
         mode=mode.to_raw(),
         append~,
         create_mode=create_mode.to_raw(),
+        lookup_flags~,
       )
     }),
     read_buf: @io.ReaderBuffer::new(),
@@ -54,7 +61,7 @@ pub fn open(
 
 ///|
 pub fn create(path : StringView) -> File raise Errno {
-  { raw: wrap(() => @raw.create(path)), read_buf: @io.ReaderBuffer::new() }
+  open(path, mode=WriteOnly, create_mode=CreateOrTruncate)
 }
 
 ///|
@@ -85,8 +92,14 @@ pub fn readdir(
   path : StringView,
   include_hidden? : Bool = true,
   sort? : Bool = false,
+  follow_symlink? : Bool = true,
 ) -> Array[String] raise Errno {
-  let result = wrap(() => @raw.readdir_names(path))
+  let lookup_flags = if follow_symlink {
+    @raw.LookupFlags::new().symlink_follow()
+  } else {
+    @raw.LookupFlags::new()
+  }
+  let result = wrap(() => @raw.readdir_names(path, lookup_flags~))
   let result = if include_hidden {
     result
   } else {
@@ -147,7 +160,13 @@ pub fn is_file(path : StringView) -> Bool raise Errno {
 ///|
 pub fn rmdir(path : StringView, recursive? : Bool = false) -> Unit raise Errno {
   if recursive {
-    for entry in readdir(path, include_hidden=true, sort=false) {
+    for
+      entry in readdir(
+        path,
+        include_hidden=true,
+        sort=false,
+        follow_symlink=false,
+      ) {
       let entry_path = path.to_owned() + "/" + entry
       remove(entry_path) catch {
         Notempty => rmdir(entry_path, recursive=true)
diff --git a/fs_test.mbt b/fs_test.mbt
index 205fbeb..33c8c47 100644
--- a/fs_test.mbt
+++ b/fs_test.mbt
@@ -12,6 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+///|
+fn host_symlink_tests_enabled() -> Bool raise Errno {
+  @miniio.get_env_var("RUNNER_OS") != Some("Windows")
+}
+
 ///|
 test "write_file supports create append and truncate" {
   let dir = "miniio_test_dir_write_file"
@@ -21,7 +26,7 @@ test "write_file supports create append and truncate" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/sample.txt"
   @miniio.write_file(path, b"hello")
@@ -43,16 +48,17 @@ test "create modes distinguish existing files" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/sample.txt"
   @miniio.write_text_file(path, "first", create_mode=CreateNew)
   inspect(@miniio.read_text_file(path), content="first")
 
-  debug_inspect(
-    try? @miniio.write_text_file(path, "second", create_mode=CreateNew),
-    content="Err(Exist)",
-  )
+  try @miniio.write_text_file(path, "second", create_mode=CreateNew) catch {
+    e => debug_inspect(e, content="Exist")
+  } noraise {
+    _ => abort("expected CreateNew to reject an existing file")
+  }
 
   @miniio.write_text_file(path, "second", create_mode=CreateOrTruncate)
   inspect(@miniio.read_text_file(path), content="second")
@@ -67,7 +73,7 @@ test "readdir sorts and filters hidden entries" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   @miniio.write_file(dir + "/b.txt", b"b")
   @miniio.write_file(dir + "/a.txt", b"a")
@@ -83,6 +89,80 @@ test "readdir sorts and filters hidden entries" {
   )
 }
 
+///|
+test "open follows symlink by default and can reject symlink" {
+  if host_symlink_tests_enabled() {
+    let target = "miniio_test_symlink_target.txt"
+    let link = "testdata/symlinks/file-link"
+    @miniio.remove(target) catch {
+      Noent => ()
+      e => raise e
+    }
+    defer (@miniio.remove(target) catch { _ => () })
+
+    @miniio.write_text_file(target, "target")
+    try @miniio.read_text_file(link) catch {
+      Noent => ()
+      e => raise e
+    } noraise {
+      content =>
+        // Windows checkouts may materialize symlink fixtures as plain text files.
+        if content == "target" {
+          let file = @miniio.create(link)
+          file.write_text("created through link")
+          file.close()
+          inspect(
+            @miniio.read_text_file(target),
+            content="created through link",
+          )
+
+          try {
+            let file = @miniio.open(link, follow_symlink=false)
+            file.close()
+            abort(
+              "expected opening a symlink with follow_symlink=false to fail",
+            )
+          } catch {
+            _ => ()
+          }
+        }
+    }
+  }
+}
+
+///|
+test "readdir follows directory symlink by default and can reject symlink" {
+  if host_symlink_tests_enabled() {
+    let dir = "miniio_test_symlink_target_dir"
+    let link = "testdata/symlinks/dir-link"
+    @miniio.remove(dir) catch {
+      Noent => ()
+      Notempty => @miniio.rmdir(dir, recursive=true)
+      e => raise e
+    }
+    @miniio.mkdir(dir)
+    defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
+
+    @miniio.write_text_file(dir + "/visible.txt", "visible")
+    @miniio.write_text_file(dir + "/.hidden", "hidden")
+
+    try @miniio.readdir(link, include_hidden=false, sort=true) catch {
+      Noent | Notdir => ()
+      e => raise e
+    } noraise {
+      entries => {
+        debug_inspect(entries, content="[\"visible.txt\"]")
+        try {
+          ignore(@miniio.readdir(link, follow_symlink=false))
+          abort("expected reading a symlink with follow_symlink=false to fail")
+        } catch {
+          _ => ()
+        }
+      }
+    }
+  }
+}
+
 ///|
 test "exists and kind classify file and directory" {
   let dir = "miniio_test_dir_kind"
@@ -92,7 +172,7 @@ test "exists and kind classify file and directory" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/sample.txt"
   @miniio.write_file(path, b"sample")
@@ -119,7 +199,7 @@ test "read_file returns io data" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/sample.txt"
   @miniio.write_text_file(path, "hello")
@@ -138,7 +218,7 @@ test "copy_file copies through reader and writer" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let src = dir + "/src.txt"
   let dst = dir + "/dst.txt"
@@ -156,7 +236,7 @@ test "json file helpers read and write json" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/config.json"
   @miniio.write_json_file(path, { "name": "miniio", "ok": true })
@@ -175,7 +255,7 @@ test "remove and recursive rmdir delete created paths" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let file_path = dir + "/sample.txt"
   let nested_dir = dir + "/nested"
@@ -185,8 +265,46 @@ test "remove and recursive rmdir delete created paths" {
   @miniio.write_file(nested_dir + "/.hidden", b"hidden")
 
   @miniio.remove_file(file_path)
-  debug_inspect(try? @miniio.remove(file_path), content="Err(Noent)")
+  try @miniio.remove(file_path) catch {
+    e => debug_inspect(e, content="Noent")
+  } noraise {
+    _ => abort("expected removing a missing file to fail")
+  }
 
   @miniio.rmdir(dir, recursive=true)
-  debug_inspect(try? @miniio.rmdir(dir), content="Err(Noent)")
+  try @miniio.rmdir(dir) catch {
+    e => debug_inspect(e, content="Noent")
+  } noraise {
+    _ => abort("expected removing a missing directory to fail")
+  }
+}
+
+///|
+test "recursive rmdir does not follow symlink root" {
+  if host_symlink_tests_enabled() {
+    let dir = "miniio_test_symlink_rmdir_target_dir"
+    let link = "testdata/symlinks/rmdir-dir-link"
+    @miniio.remove(dir) catch {
+      Noent => ()
+      Notempty => @miniio.rmdir(dir, recursive=true)
+      e => raise e
+    }
+    @miniio.mkdir(dir)
+    defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
+
+    @miniio.write_text_file(dir + "/target.txt", "keep")
+    try @miniio.readdir(link, include_hidden=false, sort=true) catch {
+      Noent | Notdir => ()
+      e => raise e
+    } noraise {
+      _ => {
+        try @miniio.rmdir(link, recursive=true) catch {
+          _ => ()
+        } noraise {
+          _ => abort("expected recursive rmdir on a symlink root to fail")
+        }
+        inspect(@miniio.read_text_file(dir + "/target.txt"), content="keep")
+      }
+    }
+  }
 }
diff --git a/internal/raw/fs.mbt b/internal/raw/fs.mbt
index 583c5ab..fe10a8c 100644
--- a/internal/raw/fs.mbt
+++ b/internal/raw/fs.mbt
@@ -225,6 +225,7 @@ pub fn open(
   mode? : Mode = ReadOnly,
   append? : Bool = false,
   create_mode? : CreateMode = OpenExisting,
+  lookup_flags? : LookupFlags = LookupFlags::new(),
 ) -> File raise Errno {
   let (base_fd, relative_path) = resolve_path(path)
   let oflags = create_mode.to_open_flags()
@@ -235,7 +236,7 @@ pub fn open(
   let needs_resize = mode is WriteOnly || mode is ReadWrite
   {
     fd: base_fd.path_open(
-      LookupFlags::new(),
+      lookup_flags,
       relative_path,
       oflags,
       file_rights(mode, needs_resize),
@@ -265,12 +266,15 @@ pub fn create(path : StringView) -> File raise Errno {
 }
 
 ///|
-fn open_dir(path : StringView) -> Fd raise Errno {
+fn open_dir(
+  path : StringView,
+  lookup_flags? : LookupFlags = LookupFlags::new(),
+) -> Fd raise Errno {
   let (base_fd, relative_path) = resolve_path(path)
   let rights = Rights::new() |> Rights::set(Fd_read) |> Rights::set(Fd_readdir)
   let oflags = OpenFlags::new() |> OpenFlags::set(Directory)
   base_fd.path_open(
-    LookupFlags::new(),
+    lookup_flags,
     relative_path,
     oflags,
     rights,
@@ -301,11 +305,12 @@ pub fn remove_dir(path : StringView) -> Unit raise Errno {
 pub fn readdir(
   path : StringView,
   buffer_size? : Int = 4096,
+  lookup_flags? : LookupFlags = LookupFlags::new(),
 ) -> Array[DirEntry] raise Errno {
   if buffer_size <= 0 {
     raise Inval
   }
-  let fd = open_dir(path)
+  let fd = open_dir(path, lookup_flags~)
   with_closed_fd(fd, fd => {
     let result : Array[DirEntry] = []
     let mut cookie : DirCookie = DirCookie(0)
@@ -345,9 +350,10 @@ pub fn readdir(
 pub fn readdir_names(
   path : StringView,
   buffer_size? : Int = 4096,
+  lookup_flags? : LookupFlags = LookupFlags::new(),
 ) -> Array[String] raise Errno {
   let names = []
-  for entry in readdir(path, buffer_size~) {
+  for entry in readdir(path, buffer_size~, lookup_flags~) {
     names.push(entry.name())
   }
   names
diff --git a/internal/raw/pkg.generated.mbti b/internal/raw/pkg.generated.mbti
index cd8ddd6..86db317 100644
--- a/internal/raw/pkg.generated.mbti
+++ b/internal/raw/pkg.generated.mbti
@@ -14,7 +14,7 @@ pub fn envs() -> Array[(String, String)] raise Errno
 
 pub fn mkdir(StringView) -> Unit raise Errno
 
-pub fn open(StringView, mode? : Mode, append? : Bool, create_mode? : CreateMode) -> File raise Errno
+pub fn open(StringView, mode? : Mode, append? : Bool, create_mode? : CreateMode, lookup_flags? : LookupFlags) -> File raise Errno
 
 pub fn open_read(StringView) -> File raise Errno
 
@@ -24,9 +24,9 @@ pub fn preopens() -> Array[String] raise Errno
 
 pub fn read_file(StringView) -> Bytes raise Errno
 
-pub fn readdir(StringView, buffer_size? : Int) -> Array[DirEntry] raise Errno
+pub fn readdir(StringView, buffer_size? : Int, lookup_flags? : LookupFlags) -> Array[DirEntry] raise Errno
 
-pub fn readdir_names(StringView, buffer_size? : Int) -> Array[String] raise Errno
+pub fn readdir_names(StringView, buffer_size? : Int, lookup_flags? : LookupFlags) -> Array[String] raise Errno
 
 pub fn remove_dir(StringView) -> Unit raise Errno
 
@@ -177,6 +177,8 @@ type FileType derive(Eq, @debug.Debug)
 type Inode derive(Eq, @debug.Debug)
 
 type LookupFlags derive(Eq, @debug.Debug)
+pub fn LookupFlags::new() -> Self
+pub fn LookupFlags::symlink_follow(Self) -> Self
 
 pub(all) enum Mode {
   ReadOnly
diff --git a/internal/raw/types.mbt b/internal/raw/types.mbt
index 440858b..4bfaebf 100644
--- a/internal/raw/types.mbt
+++ b/internal/raw/types.mbt
@@ -391,10 +391,15 @@ fn FdFlags::set(self : FdFlags, flag : FdFlag) -> FdFlags {
 struct LookupFlags(UInt) derive(Eq, Debug)
 
 ///|
-fn LookupFlags::new() -> LookupFlags {
+pub fn LookupFlags::new() -> LookupFlags {
   0
 }
 
+///|
+pub fn LookupFlags::symlink_follow(self : LookupFlags) -> LookupFlags {
+  self.0 | 1
+}
+
 ///|
 struct OpenFlags(UInt) derive(Eq, Debug)
 
diff --git a/io/data.mbt b/io/data.mbt
index b2b1483..ef8a56e 100644
--- a/io/data.mbt
+++ b/io/data.mbt
@@ -14,42 +14,42 @@
 
 ///|
 trait Data {
-  to_bytesview(Self) -> BytesView = _
-  to_bytes(Self) -> Bytes
+  fn to_bytesview(Self) -> BytesView = _
+  fn to_bytes(Self) -> Bytes
 }
 
 ///|
-impl Data with to_bytesview(self) {
+impl Data with fn to_bytesview(self) {
   self.to_bytes()[:]
 }
 
 ///|
-pub impl Data for Bytes with to_bytes(self) {
+pub impl Data for Bytes with fn to_bytes(self) {
   self
 }
 
 ///|
-pub impl Data for BytesView with to_bytes(self) {
+pub impl Data for BytesView with fn to_bytes(self) {
   self.to_owned()
 }
 
 ///|
-pub impl Data for BytesView with to_bytesview(self) {
+pub impl Data for BytesView with fn to_bytesview(self) {
   self
 }
 
 ///|
-pub impl Data for String with to_bytes(self) {
+pub impl Data for String with fn to_bytes(self) {
   @utf8.encode(self)
 }
 
 ///|
-pub impl Data for StringView with to_bytes(self) {
+pub impl Data for StringView with fn to_bytes(self) {
   @utf8.encode(self)
 }
 
 ///|
-pub impl Data for Json with to_bytes(self) {
+pub impl Data for Json with fn to_bytes(self) {
   @utf8.encode(self.stringify())
 }
 
diff --git a/io/moon.pkg b/io/moon.pkg
index 85c172f..b76f51e 100644
--- a/io/moon.pkg
+++ b/io/moon.pkg
@@ -1,7 +1,7 @@
 import {
-  "moonbit-community/miniio/internal/io_buffer" @io_buffer,
+  "moonbit-community/miniio/internal/io_buffer",
   "moonbitlang/core/cmp",
-  "moonbitlang/core/encoding/utf8" @utf8,
+  "moonbitlang/core/encoding/utf8",
   "moonbitlang/core/json",
 }
 
diff --git a/io/pkg.generated.mbti b/io/pkg.generated.mbti
index dd278c9..f343430 100644
--- a/io/pkg.generated.mbti
+++ b/io/pkg.generated.mbti
@@ -28,19 +28,19 @@ pub fn &Data::json(Self) -> Json raise
 pub fn &Data::text(Self) -> String raise
 
 pub(open) trait Reader {
-  _get_internal_buffer(Self) -> ReaderBuffer
-  _direct_read(Self, FixedArray[Byte], offset~ : Int, max_len~ : Int) -> Int raise
-  read(Self, FixedArray[Byte], offset? : Int, max_len? : Int) -> Int raise = _
-  drop(Self, Int) -> Int raise = _
-  read_exactly(Self, Int) -> Bytes raise = _
-  read_some(Self, max_len? : Int) -> Bytes? raise = _
-  read_all(Self) -> &Data raise = _
-  read_until(Self, StringView) -> String? raise = _
+  fn _get_internal_buffer(Self) -> ReaderBuffer
+  fn _direct_read(Self, FixedArray[Byte], offset~ : Int, max_len~ : Int) -> Int raise
+  fn read(Self, FixedArray[Byte], offset? : Int, max_len? : Int) -> Int raise = _
+  fn drop(Self, Int) -> Int raise = _
+  fn read_exactly(Self, Int) -> Bytes raise = _
+  fn read_some(Self, max_len? : Int) -> Bytes? raise = _
+  fn read_all(Self) -> &Data raise = _
+  fn read_until(Self, StringView) -> String? raise = _
 }
 
 pub(open) trait Writer {
-  write_once(Self, BytesView) -> Int raise
-  write(Self, &Data) -> Unit raise = _
-  write_reader(Self, &Reader) -> Unit raise = _
+  fn write_once(Self, BytesView) -> Int raise
+  fn write(Self, &Data) -> Unit raise = _
+  fn write_reader(Self, &Reader) -> Unit raise = _
 }
 
diff --git a/io/reader.mbt b/io/reader.mbt
index 0e203a0..a1d50f9 100644
--- a/io/reader.mbt
+++ b/io/reader.mbt
@@ -14,21 +14,26 @@
 
 ///|
 pub(open) trait Reader {
-  _get_internal_buffer(Self) -> ReaderBuffer
-  _direct_read(Self, FixedArray[Byte], offset~ : Int, max_len~ : Int) -> Int raise
-  read(Self, FixedArray[Byte], offset? : Int, max_len? : Int) -> Int raise = _
-  drop(Self, Int) -> Int raise = _
-  read_exactly(Self, len : Int) -> Bytes raise = _
-  read_some(Self, max_len? : Int) -> Bytes? raise = _
-  read_all(Self) -> &Data raise = _
-  read_until(Self, StringView) -> String? raise = _
+  fn _get_internal_buffer(Self) -> ReaderBuffer
+  fn _direct_read(Self, FixedArray[Byte], offset~ : Int, max_len~ : Int) -> Int raise
+  fn read(Self, FixedArray[Byte], offset? : Int, max_len? : Int) -> Int raise = _
+  fn drop(Self, Int) -> Int raise = _
+  fn read_exactly(Self, len : Int) -> Bytes raise = _
+  fn read_some(Self, max_len? : Int) -> Bytes? raise = _
+  fn read_all(Self) -> &Data raise = _
+  fn read_until(Self, StringView) -> String? raise = _
 }
 
 ///|
 pub(all) suberror ReaderClosed derive(Debug, ToJson)
 
 ///|
-impl Reader with read(self, dst, offset? = 0, max_len? = dst.length() - offset) {
+impl Reader with fn read(
+  self,
+  dst,
+  offset? = 0,
+  max_len? = dst.length() - offset,
+) {
   let buf = self._get_internal_buffer()
   if buf.len() > 0 {
     let n = @cmp.minimum(max_len, buf.len())
@@ -41,7 +46,7 @@ impl Reader with read(self, dst, offset? = 0, max_len? = dst.length() - offset)
 }
 
 ///|
-impl Reader with drop(self, len) {
+impl Reader with fn drop(self, len) {
   let buf = self._get_internal_buffer()
   if buf.len() >= len {
     buf.drop(len)
@@ -70,7 +75,7 @@ impl Reader with drop(self, len) {
 }
 
 ///|
-impl Reader with read_exactly(self, len) {
+impl Reader with fn read_exactly(self, len) {
   let buf = FixedArray::make(len, b'\x00')
   for received = 0; received < len; {
     let new_received = self.read(buf, offset=received, max_len=len - received)
@@ -83,7 +88,7 @@ impl Reader with read_exactly(self, len) {
 }
 
 ///|
-impl Reader with read_some(self, max_len?) {
+impl Reader with fn read_some(self, max_len?) {
   let buf = self._get_internal_buffer()
   if buf.len() > 0 {
     let buf_bytes = buf.buf().unsafe_reinterpret_as_bytes()
@@ -115,7 +120,7 @@ impl Reader with read_some(self, max_len?) {
 }
 
 ///|
-impl Reader with read_all(self) {
+impl Reader with fn read_all(self) {
   let buffer_list = []
   let mut buffer = FixedArray::make(1024, b'\x00')
   let mut offset = 0
@@ -138,7 +143,7 @@ impl Reader with read_all(self) {
 }
 
 ///|
-impl Reader with read_until(self, sep) {
+impl Reader with fn read_until(self, sep) {
   let sep = @utf8.encode(sep)
   let buf = self._get_internal_buffer()
   match buf.find_opt(sep, reader=self) {
diff --git a/io/writer.mbt b/io/writer.mbt
index 20b9b8b..6bf2646 100644
--- a/io/writer.mbt
+++ b/io/writer.mbt
@@ -14,13 +14,13 @@
 
 ///|
 pub(open) trait Writer {
-  write_once(Self, BytesView) -> Int raise
-  write(Self, &Data) -> Unit raise = _
-  write_reader(Self, &Reader) -> Unit raise = _
+  fn write_once(Self, BytesView) -> Int raise
+  fn write(Self, &Data) -> Unit raise = _
+  fn write_reader(Self, &Reader) -> Unit raise = _
 }
 
 ///|
-impl Writer with write(self, data) {
+impl Writer with fn write(self, data) {
   let mut view = data.to_bytesview()
   while view.length() > 0 {
     let written = self.write_once(view)
@@ -29,7 +29,7 @@ impl Writer with write(self, data) {
 }
 
 ///|
-impl Writer with write_reader(self, reader) {
+impl Writer with fn write_reader(self, reader) {
   let buf = reader._get_internal_buffer()
   if buf.len() > 0 {
     let buf_bytes = buf.buf().unsafe_reinterpret_as_bytes()
diff --git a/io_test.mbt b/io_test.mbt
index 8d723a1..cf7336d 100644
--- a/io_test.mbt
+++ b/io_test.mbt
@@ -21,7 +21,7 @@ test "file implements io reader and writer" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let path = dir + "/sample.txt"
   let writer = @miniio.create(path)
@@ -47,7 +47,7 @@ test "write_reader copies file content" {
     e => raise e
   }
   @miniio.mkdir(dir)
-  defer ignore(try? @miniio.rmdir(dir, recursive=true))
+  defer (@miniio.rmdir(dir, recursive=true) catch { _ => () })
 
   let src_path = dir + "/src.txt"
   let dst_path = dir + "/dst.txt"
diff --git a/moon.mod b/moon.mod
new file mode 100644
index 0000000..2fde47d
--- /dev/null
+++ b/moon.mod
@@ -0,0 +1,15 @@
+name = "moonbit-community/miniio"
+
+version = "0.2.1"
+
+description = "Small, portable WASIp1 I/O SDK for building MoonBit CLI tools and agent skills."
+
+keywords = [ "wasi", "wasip1", "io", "cli", "agent" ]
+
+readme = "README.md"
+
+repository = "https://github.com/moonbit-community/miniio"
+
+license = "Apache-2.0"
+
+preferred_target = "wasm"
diff --git a/moon.mod.json b/moon.mod.json
deleted file mode 100644
index bc8d357..0000000
--- a/moon.mod.json
+++ /dev/null
@@ -1,10 +0,0 @@
-{
-  "name": "moonbit-community/miniio",
-  "version": "0.2.0",
-  "description": "Small, portable WASIp1 I/O SDK for building MoonBit CLI tools and agent skills.",
-  "keywords": ["wasi", "wasip1", "io", "cli", "agent"],
-  "readme": "README.md",
-  "repository": "https://github.com/moonbit-community/miniio",
-  "license": "Apache-2.0",
-  "preferred-target": "wasm"
-}
diff --git a/moon.pkg b/moon.pkg
index a3205e4..4566bc6 100644
--- a/moon.pkg
+++ b/moon.pkg
@@ -1,6 +1,6 @@
 import {
-  "moonbit-community/miniio/io" @io,
-  "moonbit-community/miniio/internal/raw" @raw,
+  "moonbit-community/miniio/io",
+  "moonbit-community/miniio/internal/raw",
 }
 
 supported_targets = "wasm"
diff --git a/pkg.generated.mbti b/pkg.generated.mbti
index 00f2b1c..61d6c84 100644
--- a/pkg.generated.mbti
+++ b/pkg.generated.mbti
@@ -31,7 +31,7 @@ pub fn kind(StringView) -> FileKind raise Errno
 
 pub fn mkdir(StringView) -> Unit raise Errno
 
-pub fn open(StringView, mode? : Mode, append? : Bool, create_mode? : CreateMode) -> File raise Errno
+pub fn open(StringView, mode? : Mode, append? : Bool, create_mode? : CreateMode, follow_symlink? : Bool) -> File raise Errno
 
 pub fn read_file(StringView) -> &@io.Data raise Errno
 
@@ -39,7 +39,7 @@ pub fn read_json_file(StringView) -> Json raise Errno
 
 pub fn read_text_file(StringView) -> String raise Errno
 
-pub fn readdir(StringView, include_hidden? : Bool, sort? : Bool) -> Array[String] raise Errno
+pub fn readdir(StringView, include_hidden? : Bool, sort? : Bool, follow_symlink? : Bool) -> Array[String] raise Errno
 
 pub fn remove(StringView) -> Unit raise Errno
 
diff --git a/testdata/symlinks/dir-link b/testdata/symlinks/dir-link
new file mode 120000
index 0000000..b0ae6ca
--- /dev/null
+++ b/testdata/symlinks/dir-link
@@ -0,0 +1 @@
+../../miniio_test_symlink_target_dir
\ No newline at end of file
diff --git a/testdata/symlinks/file-link b/testdata/symlinks/file-link
new file mode 120000
index 0000000..c9b2edf
--- /dev/null
+++ b/testdata/symlinks/file-link
@@ -0,0 +1 @@
+../../miniio_test_symlink_target.txt
\ No newline at end of file
diff --git a/testdata/symlinks/rmdir-dir-link b/testdata/symlinks/rmdir-dir-link
new file mode 120000
index 0000000..45bffdf
--- /dev/null
+++ b/testdata/symlinks/rmdir-dir-link
@@ -0,0 +1 @@
+../../miniio_test_symlink_rmdir_target_dir
\ No newline at end of file
diff --git a/types.mbt b/types.mbt
index b5b66df..c3e2f56 100644
--- a/types.mbt
+++ b/types.mbt
@@ -157,7 +157,7 @@ pub(all) suberror Errno {
 } derive(Eq, Debug)
 
 ///|
-pub impl Show for Errno with to_string(self) {
+pub impl Show for Errno with fn to_string(self) {
   match self {
     Success => "Success"
     TooBig => "TooBig"
@@ -240,7 +240,7 @@ pub impl Show for Errno with to_string(self) {
 }
 
 ///|
-pub impl Show for Errno with output(self, logger) {
+pub impl Show for Errno with fn output(self, logger) {
   logger.write_string(self.to_string())
 }