diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 38b8d37..49e026f 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -12,10 +12,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: install
-        run: |
-          curl -fsSL https://cli.moonbitlang.com/install/unix.sh | bash
-          echo "$HOME/.moon/bin" >> $GITHUB_PATH
+      - name: Setup Moonbit
+        uses: hustcer/setup-moonbit@v1
+        # with:
+        #   version: "nightly"
 
       # - name: moon check
       #   run: moon check
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000..fcd5a68
--- /dev/null
+++ b/.github/workflows/release.yml
@@ -0,0 +1,30 @@
+name: release
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  publish:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Moonbit
+        uses: hustcer/setup-moonbit@v1
+        # with:
+        #   version: "nightly"
+
+      - name: moon check
+        run: moon update && moon version && moon check --target js
+
+      - name: moon test
+        run: moon build --target js --debug
+
+      - name: setup credentials
+        run: |
+          mkdir -p ~/.moon
+          echo '${{ secrets.MOON_CREDENTIALS }}' > ~/.moon/credentials.json
+
+      - name: moon publish
+        run: moon publish
diff --git a/.gitignore b/.gitignore
index cdc7314..0ced372 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,7 @@ trace.json
 .DS_Store
 
 *.mbti
+
+_build
+
+.github/skills/
diff --git a/moon.mod.json b/moon.mod.json
index ab3baaa..8839161 100644
--- a/moon.mod.json
+++ b/moon.mod.json
@@ -1,6 +1,6 @@
 {
   "name": "tiye/cirru-parser",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "deps": {},
   "readme": "README.md",
   "repository": "https://github.com/Cirru/parser.mbt",
diff --git a/src/main/main.mbt b/src/main/main.mbt
index 3317eec..eb357e6 100644
--- a/src/main/main.mbt
+++ b/src/main/main.mbt
@@ -33,13 +33,13 @@ pub fn main_writer() -> Unit {
   let demo = "unfolding"
   let demo_file = fsReadSync("./test/cirru/\{demo}.cirru")
   let json_file = fsReadSync("./test/data/\{demo}.json")
-  let defined = (try? @json.parse(json_file)).unwrap()
-  let tree : Array[Cirru] = (try? @json.from_json(defined)).unwrap()
+  let defined = try! @json.parse(json_file)
+  let tree : Array[Cirru] = try! @json.from_json(defined)
   println("TREE:")
   for item in tree {
     println(item.to_json().stringify())
   }
-  let ret = (try? Cirru::format(tree, use_inline=false)).unwrap()
+  let ret = try! Cirru::format(tree, use_inline=false)
   println("Generated:")
   println(ret)
   println("Expected:")
diff --git a/src/main/moon.pkg b/src/main/moon.pkg
new file mode 100644
index 0000000..d73e79c
--- /dev/null
+++ b/src/main/moon.pkg
@@ -0,0 +1,11 @@
+import {
+  "moonbitlang/core/json" @json,
+  "tiye/cirru-parser" @lib,
+}
+
+import {
+} for "test"
+
+options(
+  "is-main": true,
+)
\ No newline at end of file
diff --git a/src/main/moon.pkg.json b/src/main/moon.pkg.json
deleted file mode 100644
index 1fe5a54..0000000
--- a/src/main/moon.pkg.json
+++ /dev/null
@@ -1,10 +0,0 @@
-{
-  "is-main": true,
-  "import": [
-    {
-      "path": "tiye/cirru-parser",
-      "alias": "lib"
-    }
-  ],
-  "test-import": []
-}
diff --git a/src/moon.pkg b/src/moon.pkg
new file mode 100644
index 0000000..e3dc4a7
--- /dev/null
+++ b/src/moon.pkg
@@ -0,0 +1,8 @@
+import {
+  "moonbitlang/core/cmp" @cmp,
+  "moonbitlang/core/json" @json,
+}
+
+import {
+  "tiye/cirru-parser" @lib,
+} for "test"
\ No newline at end of file
diff --git a/src/moon.pkg.json b/src/moon.pkg.json
deleted file mode 100644
index 7b70eee..0000000
--- a/src/moon.pkg.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "import": [],
-  "test-import": [
-    {
-      "path": "tiye/cirru-parser",
-      "alias": "lib"
-    }
-  ]
-}
diff --git a/src/parser.mbt b/src/parser.mbt
index 0537db7..0f8f995 100644
--- a/src/parser.mbt
+++ b/src/parser.mbt
@@ -69,7 +69,9 @@ pub fn Cirru::parse(code : String) -> Array[Cirru] raise CirruParseError {
 }
 
 ///|
-suberror CirruParseError String
+suberror CirruParseError {
+  CirruParseError(String)
+}
 
 ///|
 /// display Cirru parse error
diff --git a/src/parser_test.mbt b/src/parser_test.mbt
index c7f8a1a..3946a9c 100644
--- a/src/parser_test.mbt
+++ b/src/parser_test.mbt
@@ -16,12 +16,12 @@ test "existed demos" {
   for demo in demos {
     let demo_file = fsReadSync("./test/cirru/\{demo}.cirru")
     let json_file = fsReadSync("./test/data/\{demo}.json")
-    let tree = (try? Cirru::parse(demo_file)).unwrap().to_json().stringify()
-    let defined = (try? @json.parse(json_file)).unwrap()
+    let tree = (try! Cirru::parse(demo_file)).to_json().stringify()
+    let defined = try! @json.parse(json_file)
     let defined_str = defined.stringify()
     assert_eq(tree, defined_str)
     let formatted = Cirru::format(@json.from_json(defined), use_inline=false)
-    let ret = (try? Cirru::parse(formatted)).unwrap().to_json().stringify()
+    let ret = (try! Cirru::parse(formatted)).to_json().stringify()
     assert_eq(ret, defined_str)
   }
 }
diff --git a/src/s_expr.mbt b/src/s_expr.mbt
index 37b0bb2..15eb5c3 100644
--- a/src/s_expr.mbt
+++ b/src/s_expr.mbt
@@ -1,5 +1,7 @@
 ///|
-suberror FormatError String
+suberror FormatError {
+  FormatError(String)
+}
 
 ///|
 /// format program to Cirru to Lisp-like code
@@ -56,7 +58,7 @@ fn Cirru::format_lispy_expr(
       } else {
         let s0 = token[0]
         if s0 == '|' || s0 == '"' {
-          let sliced = (try? token[1:]).unwrap().to_string()
+          let sliced = (try! token[1:]).to_string()
           "\"" + escape_string(sliced) + "\""
         } else if token.contains(" ") ||
           token.contains("\n") ||
diff --git a/src/writer.mbt b/src/writer.mbt
index 3e30068..5cad15c 100644
--- a/src/writer.mbt
+++ b/src/writer.mbt
@@ -168,7 +168,9 @@ fn Cirru::get_node_kind(self : Cirru) -> WriterNode {
 }
 
 ///|
-pub(all) suberror FormatCirruError String derive(Show)
+pub(all) suberror FormatCirruError {
+  FormatCirruError(String)
+} derive(Show)
 
 ///|
 fn generate_tree(