🎉 initial commit: Nyash Programming Language完成版

🚀 主要機能:
• Everything is Box哲学による革新的アーキテクチャ
• WebAssemblyブラウザー対応プレイグラウンド
• アーティスト協同制作デモ - 複数Boxインスタンス実証
• 視覚的デバッグシステム - DebugBox完全統合
• static box Mainパターン - メモリ安全設計

⚡ 言語機能:
• NOT/AND/OR/除算演算子完全実装
• ジェネリクス/テンプレートシステム
• 非同期処理(nowait/await)
• try/catchエラーハンドリング
• Canvas統合グラフィックス

🎨 ブラウザー体験:
• 9種類のインタラクティブデモ
• リアルタイムコード実行
• WebCanvas/WebConsole/WebDisplay
• モバイル対応完了

🤖 Built with Claude Code collaboration
Ready for public release!

src/boxes/string_box.rs

@@ -0,0 +1,141 @@
+// StringBox implementation - String values in Nyash
+use crate::box_trait::NyashBox;
+use std::any::Any;
+use std::fmt::Display;
+
+/// String values in Nyash - UTF-8 encoded text
+#[derive(Debug, Clone, PartialEq)]
+pub struct StringBox {
+    pub value: String,
+    id: u64,
+}
+
+impl StringBox {
+    pub fn new(value: impl Into<String>) -> Self {
+        static mut COUNTER: u64 = 0;
+        let id = unsafe {
+            COUNTER += 1;
+            COUNTER
+        };
+        
+        Self {
+            value: value.into(),
+            id,
+        }
+    }
+    
+    pub fn empty() -> Self {
+        Self::new("")
+    }
+    
+    // ===== String Methods for Nyash =====
+    
+    /// Split string by delimiter and return ArrayBox
+    pub fn split(&self, delimiter: &str) -> Box<dyn NyashBox> {
+        use crate::box_trait::ArrayBox;
+        let parts: Vec<String> = self.value.split(delimiter).map(|s| s.to_string()).collect();
+        let array_elements: Vec<Box<dyn NyashBox>> = parts.into_iter()
+            .map(|s| Box::new(StringBox::new(s)) as Box<dyn NyashBox>)
+            .collect();
+        Box::new(ArrayBox::new_with_elements(array_elements))
+    }
+    
+    /// Find substring and return position (or -1 if not found)
+    pub fn find(&self, search: &str) -> Box<dyn NyashBox> {
+        use crate::boxes::IntegerBox;
+        match self.value.find(search) {
+            Some(pos) => Box::new(IntegerBox::new(pos as i64)),
+            None => Box::new(IntegerBox::new(-1)),
+        }
+    }
+    
+    /// Replace all occurrences of old with new
+    pub fn replace(&self, old: &str, new: &str) -> Box<dyn NyashBox> {
+        Box::new(StringBox::new(self.value.replace(old, new)))
+    }
+    
+    /// Trim whitespace from both ends
+    pub fn trim(&self) -> Box<dyn NyashBox> {
+        Box::new(StringBox::new(self.value.trim()))
+    }
+    
+    /// Convert to uppercase
+    pub fn to_upper(&self) -> Box<dyn NyashBox> {
+        Box::new(StringBox::new(self.value.to_uppercase()))
+    }
+    
+    /// Convert to lowercase  
+    pub fn to_lower(&self) -> Box<dyn NyashBox> {
+        Box::new(StringBox::new(self.value.to_lowercase()))
+    }
+    
+    /// Check if string contains substring
+    pub fn contains(&self, search: &str) -> Box<dyn NyashBox> {
+        use crate::boxes::BoolBox;
+        Box::new(BoolBox::new(self.value.contains(search)))
+    }
+    
+    /// Check if string starts with prefix
+    pub fn starts_with(&self, prefix: &str) -> Box<dyn NyashBox> {
+        use crate::boxes::BoolBox;
+        Box::new(BoolBox::new(self.value.starts_with(prefix)))
+    }
+    
+    /// Check if string ends with suffix
+    pub fn ends_with(&self, suffix: &str) -> Box<dyn NyashBox> {
+        use crate::boxes::BoolBox;
+        Box::new(BoolBox::new(self.value.ends_with(suffix)))
+    }
+    
+    /// Join array elements using this string as delimiter
+    pub fn join(&self, array_box: Box<dyn NyashBox>) -> Box<dyn NyashBox> {
+        use crate::box_trait::ArrayBox;
+        if let Some(array) = array_box.as_any().downcast_ref::<ArrayBox>() {
+            let strings: Vec<String> = array.elements.lock().unwrap()
+                .iter()
+                .map(|element| element.to_string_box().value)
+                .collect();
+            Box::new(StringBox::new(strings.join(&self.value)))
+        } else {
+            // If not an ArrayBox, treat as single element
+            Box::new(StringBox::new(array_box.to_string_box().value))
+        }
+    }
+}
+
+impl NyashBox for StringBox {
+    fn to_string_box(&self) -> crate::box_trait::StringBox {
+        crate::box_trait::StringBox::new(self.value.clone())
+    }
+    
+    fn equals(&self, other: &dyn NyashBox) -> crate::box_trait::BoolBox {
+        use crate::box_trait::BoolBox;
+        if let Some(other_string) = other.as_any().downcast_ref::<StringBox>() {
+            BoolBox::new(self.value == other_string.value)
+        } else {
+            BoolBox::new(false)
+        }
+    }
+    
+    fn type_name(&self) -> &'static str {
+        "StringBox"
+    }
+    
+    fn clone_box(&self) -> Box<dyn NyashBox> {
+        Box::new(self.clone())
+    }
+    
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+    
+    fn box_id(&self) -> u64 {
+        self.id
+    }
+}
+
+impl Display for StringBox {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.value)
+    }
+}