feat: Add Christmas tree demo and enable incremental output from WASM to the UI.

Author: zuisong

demo_codes/christmas_tree.ch

@@ -0,0 +1,42 @@
+let println = import "stdlib/io".println
+
+# 简单的字符串重复函数
+def repeat(str, count) {
+    let res = ""
+    let i = 0
+    for i < count {
+        res = res + str
+        i = i + 1
+    }
+    return res
+}
+
+def print_tree(height) {
+    println("🎄 Merry Christmas! 🎄")
+    println("")
+
+    # 打印树冠
+    let i = 1
+    for i <= height {
+        let spaces = repeat(" ", height - i)
+        # 装饰一点彩灯（简单随机模拟：用不同字符？）
+        # 这里仅用星星
+        let stars = repeat("*", 2 * i - 1)
+        println(spaces + stars)
+        i = i + 1
+    }
+
+    # 打印树干
+    let trunk_padding = repeat(" ", height - 2)
+    
+    let j = 0
+    for j < 2 {
+        println(trunk_padding + "###")
+        j = j + 1
+    }
+    
+    println("")
+    println(repeat(" ", height - 4) + "Happy New Year!")
+}
+
+print_tree(10)

docs/index.html

@@ -38,6 +38,7 @@ <h1>Chen Lang <span>Playground</span></h1>
             <option value="async_task">Coroutines</option>
             <option value="async_http">Async HTTP Request</option>
             <option value="concurrent_http">Concurrent HTTP</option>
+            <option value="christmas_tree">Christmas Tree</option>
           </select>
         </div>
         <button id="run">

docs/index.js

@@ -364,6 +364,48 @@ println("All requests completed!")
 println("Request 1 status: " + results[0])
 println("Request 2 status: " + results[1])
 println("Request 3 UUID: " + results[2])
+`,
+    christmas_tree: `# Merry Christmas!
+let println = import "stdlib/io".println
+
+# Simple string repeat function
+def repeat(str, count) {
+    let res = ""
+    let i = 0
+    for i < count {
+        res = res + str
+        i = i + 1
+    }
+    return res
+}
+
+def print_tree(height) {
+    println("🎄 Merry Christmas! 🎄")
+    println("")
+
+    # Print leaves
+    let i = 1
+    for i <= height {
+        let spaces = repeat(" ", height - i)
+        let stars = repeat("*", 2 * i - 1)
+        println(spaces + stars)
+        i = i + 1
+    }
+
+    # Print trunk
+    let trunk_padding = repeat(" ", height - 2)
+    
+    let j = 0
+    for j < 2 {
+        println(trunk_padding + "###")
+        j = j + 1
+    }
+    
+    println("")
+    println(repeat(" ", height - 4) + "Happy New Year!")
+}
+
+print_tree(10)
 `
 };
 
@@ -455,11 +497,20 @@ async function run() {
 
     runBtn.addEventListener('click', async () => {
         const code = codeArea.value;
+        outputArea.textContent = '';
+
+        window.print_output = (text) => {
+            outputArea.textContent += text;
+            outputArea.scrollTop = outputArea.scrollHeight;
+        };
+
         try {
             const result = await run_wasm(code);
-            outputArea.textContent = result;
+            if (result) outputArea.textContent += result;
         } catch (e) {
-            outputArea.textContent = `Error: ${e}`;
+            outputArea.textContent += `Error: ${e}`;
+        } finally {
+            window.print_output = null;
         }
     });
 

docs/pkg/chen_lang.d.ts

@@ -9,11 +9,11 @@ export interface InitOutput {
   readonly memory: WebAssembly.Memory;
   readonly run: (a: number, b: number) => void;
   readonly run_wasm: (a: number, b: number) => any;
-  readonly wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue_____: (a: number, b: number, c: any) => void;
-  readonly wasm_bindgen_47816a2d43ec07ce___closure__destroy___dyn_core_3cd24c61823388c3___ops__function__FnMut__wasm_bindgen_47816a2d43ec07ce___JsValue____Output_______: (a: number, b: number) => void;
-  readonly wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke______: (a: number, b: number) => void;
-  readonly wasm_bindgen_47816a2d43ec07ce___closure__destroy___dyn_core_3cd24c61823388c3___ops__function__FnMut_____Output_______: (a: number, b: number) => void;
-  readonly wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue__wasm_bindgen_47816a2d43ec07ce___JsValue_____: (a: number, b: number, c: any, d: any) => void;
+  readonly wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue_____: (a: number, b: number, c: any) => void;
+  readonly wasm_bindgen_3453c9d0e447211b___closure__destroy___dyn_core_1ea7ec8b69c1cd75___ops__function__FnMut__wasm_bindgen_3453c9d0e447211b___JsValue____Output_______: (a: number, b: number) => void;
+  readonly wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke______: (a: number, b: number) => void;
+  readonly wasm_bindgen_3453c9d0e447211b___closure__destroy___dyn_core_1ea7ec8b69c1cd75___ops__function__FnMut_____Output_______: (a: number, b: number) => void;
+  readonly wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue__wasm_bindgen_3453c9d0e447211b___JsValue_____: (a: number, b: number, c: any, d: any) => void;
   readonly __wbindgen_malloc: (a: number, b: number) => number;
   readonly __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
   readonly __wbindgen_exn_store: (a: number) => void;

docs/pkg/chen_lang.js

@@ -208,16 +208,16 @@ if (!('encodeInto' in cachedTextEncoder)) {
 
 let WASM_VECTOR_LEN = 0;
 
-function wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue_____(arg0, arg1, arg2) {
-    wasm.wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue_____(arg0, arg1, arg2);
+function wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue_____(arg0, arg1, arg2) {
+    wasm.wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue_____(arg0, arg1, arg2);
 }
 
-function wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke______(arg0, arg1) {
-    wasm.wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke______(arg0, arg1);
+function wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke______(arg0, arg1) {
+    wasm.wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke______(arg0, arg1);
 }
 
-function wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue__wasm_bindgen_47816a2d43ec07ce___JsValue_____(arg0, arg1, arg2, arg3) {
-    wasm.wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue__wasm_bindgen_47816a2d43ec07ce___JsValue_____(arg0, arg1, arg2, arg3);
+function wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue__wasm_bindgen_3453c9d0e447211b___JsValue_____(arg0, arg1, arg2, arg3) {
+    wasm.wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue__wasm_bindgen_3453c9d0e447211b___JsValue_____(arg0, arg1, arg2, arg3);
 }
 
 const __wbindgen_enum_RequestCache = ["default", "no-store", "reload", "no-cache", "force-cache", "only-if-cached"];
@@ -403,7 +403,7 @@ function __wbg_get_imports() {
                 const a = state0.a;
                 state0.a = 0;
                 try {
-                    return wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue__wasm_bindgen_47816a2d43ec07ce___JsValue_____(a, state0.b, arg0, arg1);
+                    return wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue__wasm_bindgen_3453c9d0e447211b___JsValue_____(a, state0.b, arg0, arg1);
                 } finally {
                     state0.a = a;
                 }
@@ -430,6 +430,9 @@ function __wbg_get_imports() {
         const ret = arg0.next();
         return ret;
     }, arguments) };
+    imports.wbg.__wbg_print_output_0fa5b8f975cf9b66 = function(arg0, arg1) {
+        print_output(getStringFromWasm0(arg0, arg1));
+    };
     imports.wbg.__wbg_queueMicrotask_9b549dfce8865860 = function(arg0) {
         const ret = arg0.queueMicrotask;
         return ret;
@@ -519,7 +522,7 @@ function __wbg_get_imports() {
     };
     imports.wbg.__wbindgen_cast_06ecd7d2bbdbbef7 = function(arg0, arg1) {
         // Cast intrinsic for `Closure(Closure { dtor_idx: 278, function: Function { arguments: [], shim_idx: 279, ret: Unit, inner_ret: Some(Unit) }, mutable: true }) -> Externref`.
-        const ret = makeMutClosure(arg0, arg1, wasm.wasm_bindgen_47816a2d43ec07ce___closure__destroy___dyn_core_3cd24c61823388c3___ops__function__FnMut_____Output_______, wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke______);
+        const ret = makeMutClosure(arg0, arg1, wasm.wasm_bindgen_3453c9d0e447211b___closure__destroy___dyn_core_1ea7ec8b69c1cd75___ops__function__FnMut_____Output_______, wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke______);
         return ret;
     };
     imports.wbg.__wbindgen_cast_2241b6af4c4b2941 = function(arg0, arg1) {
@@ -529,7 +532,7 @@ function __wbg_get_imports() {
     };
     imports.wbg.__wbindgen_cast_b1bcbba6fa3c236c = function(arg0, arg1) {
         // Cast intrinsic for `Closure(Closure { dtor_idx: 357, function: Function { arguments: [Externref], shim_idx: 358, ret: Unit, inner_ret: Some(Unit) }, mutable: true }) -> Externref`.
-        const ret = makeMutClosure(arg0, arg1, wasm.wasm_bindgen_47816a2d43ec07ce___closure__destroy___dyn_core_3cd24c61823388c3___ops__function__FnMut__wasm_bindgen_47816a2d43ec07ce___JsValue____Output_______, wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue_____);
+        const ret = makeMutClosure(arg0, arg1, wasm.wasm_bindgen_3453c9d0e447211b___closure__destroy___dyn_core_1ea7ec8b69c1cd75___ops__function__FnMut__wasm_bindgen_3453c9d0e447211b___JsValue____Output_______, wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue_____);
         return ret;
     };
     imports.wbg.__wbindgen_init_externref_table = function() {

docs/pkg/chen_lang_bg.wasm

@@ -3,11 +3,11 @@
 export const memory: WebAssembly.Memory;
 export const run: (a: number, b: number) => void;
 export const run_wasm: (a: number, b: number) => any;
-export const wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue_____: (a: number, b: number, c: any) => void;
-export const wasm_bindgen_47816a2d43ec07ce___closure__destroy___dyn_core_3cd24c61823388c3___ops__function__FnMut__wasm_bindgen_47816a2d43ec07ce___JsValue____Output_______: (a: number, b: number) => void;
-export const wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke______: (a: number, b: number) => void;
-export const wasm_bindgen_47816a2d43ec07ce___closure__destroy___dyn_core_3cd24c61823388c3___ops__function__FnMut_____Output_______: (a: number, b: number) => void;
-export const wasm_bindgen_47816a2d43ec07ce___convert__closures_____invoke___wasm_bindgen_47816a2d43ec07ce___JsValue__wasm_bindgen_47816a2d43ec07ce___JsValue_____: (a: number, b: number, c: any, d: any) => void;
+export const wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue_____: (a: number, b: number, c: any) => void;
+export const wasm_bindgen_3453c9d0e447211b___closure__destroy___dyn_core_1ea7ec8b69c1cd75___ops__function__FnMut__wasm_bindgen_3453c9d0e447211b___JsValue____Output_______: (a: number, b: number) => void;
+export const wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke______: (a: number, b: number) => void;
+export const wasm_bindgen_3453c9d0e447211b___closure__destroy___dyn_core_1ea7ec8b69c1cd75___ops__function__FnMut_____Output_______: (a: number, b: number) => void;
+export const wasm_bindgen_3453c9d0e447211b___convert__closures_____invoke___wasm_bindgen_3453c9d0e447211b___JsValue__wasm_bindgen_3453c9d0e447211b___JsValue_____: (a: number, b: number, c: any, d: any) => void;
 export const __wbindgen_malloc: (a: number, b: number) => number;
 export const __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
 export const __wbindgen_exn_store: (a: number) => void;

docs/pkg/chen_lang_bg.wasm.d.ts

@@ -191,6 +191,28 @@ fn get_line_range(code: &str, line: u32) -> Range<usize> {
     if len > 0 { len - 1..len } else { 0..0 }
 }
 
+#[cfg(all(feature = "wasm", target_arch = "wasm32"))]
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(js_name = print_output)]
+    fn print_output(s: &str);
+}
+
+#[cfg(all(feature = "wasm", target_arch = "wasm32"))]
+struct RealtimeWriter;
+
+#[cfg(all(feature = "wasm", target_arch = "wasm32"))]
+impl Write for RealtimeWriter {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        let s = String::from_utf8_lossy(buf);
+        print_output(&s);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
 #[cfg(all(feature = "wasm", target_arch = "wasm32"))]
 #[wasm_bindgen]
 pub async fn run_wasm(code: String) -> String {
@@ -201,17 +223,15 @@ pub async fn run_wasm(code: String) -> String {
 
         let program = compiler::compile(&code.chars().collect::<Vec<char>>(), ast);
 
-        let output = Arc::new(Mutex::new(Vec::new()));
-        let writer = SharedWriter(output.clone());
+        let writer = RealtimeWriter;
 
         {
             let mut vm = vm::VM::with_writer(Box::new(writer));
             // Execute async to handle HTTP requests and other async operations
             let _result = vm.execute_async(Rc::new(program)).await?;
         }
 
-        let output_vec = output.lock().unwrap().clone();
-        Ok::<String, ChenError>(String::from_utf8(output_vec)?)
+        Ok::<String, ChenError>(String::new())
     }
     .await;