更新GitHub工作流，添加对examples目录存在性的检查，若不存在则创建空目录并添加README.md文件

Author: HelloAIXIAOJI

.github/workflows/build_interpreter.yml

@@ -60,15 +60,31 @@ jobs:
       if: matrix.os == 'windows-latest'
       run: |
         cp target/release/codenothing.exe release-package/
-        cp -r examples release-package/
+        # 如果examples目录存在，则复制
+        if [ -d "examples" ]; then
+          cp -r examples release-package/
+        else
+          echo "警告：examples目录不存在，跳过复制"
+          # 创建一个空的examples目录，确保有内容
+          mkdir -p release-package/examples
+          echo "# CodeNothing 示例" > release-package/examples/README.md
+        fi
         7z a ${{ matrix.asset_name }} ./release-package/*
       shell: bash
 
     - name: 打包Linux/macOS
       if: matrix.os != 'windows-latest'
       run: |
         cp target/release/codenothing release-package/
-        cp -r examples release-package/
+        # 如果examples目录存在，则复制
+        if [ -d "examples" ]; then
+          cp -r examples release-package/
+        else
+          echo "警告：examples目录不存在，跳过复制"
+          # 创建一个空的examples目录，确保有内容
+          mkdir -p release-package/examples
+          echo "# CodeNothing 示例" > release-package/examples/README.md
+        fi
         tar -czvf ${{ matrix.asset_name }} -C release-package .
       shell: bash
 

library_io/src/lib.rs

@@ -10,6 +10,7 @@ use cn_common::string::process_escape_chars;
 mod std {
     use super::*;
     use ::std::fmt::Write;
+    use ::std::io::Write;
 
     // 打印字符串到标准输出
     pub fn cn_print(args: Vec<String>) -> String {