feat: 重构main函数，添加run_file和run_repl函数以支持从文件和REPL读取输入

src/main.rs

@@ -9,45 +9,86 @@ use parser::Parser;
 use interpreter::Interpreter;
 use std::env;
 use std::fs;
-use std::io::{self, Read};
-
-fn main() {
-    let src = match env::args().len() {
-        1 => {
-            // 无参数：从 stdin 读取
-            let mut buf = String::new();
-            if let Err(e) = io::stdin().read_to_string(&mut buf) {
-                eprintln!("Failed to read stdin: {}", e);
-                std::process::exit(1);
-            }
-            buf
-        }
-        2 => {
-            // 一个参数：作为文件路径
-            let path = env::args().nth(1).unwrap();
-            match fs::read_to_string(&path) {
-                Ok(s) => s,
-                Err(e) => {
-                    eprintln!("Failed to read file '{}': {}", path, e);
-                    std::process::exit(1);
-                }
-            }
-        }
-        _ => {
-            eprintln!("Usage: aster [script_file]");
-            eprintln!("  aster          - run from stdin");
-            eprintln!("  aster <file>   - run script file");
-            std::process::exit(1);
-        }
-    };
+use std::io::Write;
+use std::io::stdin;
+use std::io::stdout;
 
+fn run_file(src: String) {
     let tokens = Lexer::new(&src).tokenize();
     let mut parser = Parser::new(tokens);
     let stmts = parser.parse();
 
     let mut interpreter = Interpreter::new();
     if let Err(e) = interpreter.interpret(stmts) {
-        eprintln!("{}", e);
+        eprintln!("Error: {}", e);
         std::process::exit(1);
     }
 }
+
+fn run_repl() {
+    println!("Welcome to Aster REPL!");
+    println!("Type ':exit' to quit.");
+    println!("Type ':reset' to reset the interpreter state.");
+
+    let mut interpreter = Interpreter::new();
+    let mut line = String::new();
+
+    loop {
+        print!(">>> ");
+        stdout().flush().unwrap();
+
+        line.clear();
+        if let Err(e) = stdin().read_line(&mut line) {
+            eprintln!("Error reading input: {}", e);
+            continue;
+        }
+
+        let line = line.trim();
+        if line.is_empty() {
+            continue;
+        }
+
+        match line {
+            ":exit" => {
+                println!("Goodbye!");
+                break;
+            }
+            ":reset" => {
+                interpreter = Interpreter::new();
+                println!("Interpreter reset.");
+                continue;
+            }
+            _ => {}
+        }
+
+        let tokens = Lexer::new(line).tokenize();
+        let mut parser = Parser::new(tokens);
+        let stmts = parser.parse();
+
+        if let Err(e) = interpreter.interpret(stmts) {
+            eprintln!("Error: {}", e);
+        }
+    }
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    match args.len() {
+        1 => run_repl(),
+        2 => {
+            let filename = &args[1];
+            match fs::read_to_string(filename) {
+                Ok(src) => run_file(src),
+                Err(e) => {
+                    eprintln!("Error reading file '{}': {}", filename, e);
+                    std::process::exit(1);
+                }
+            }
+        }
+        _ => {
+            eprintln!("Usage: aster [script]");
+            std::process::exit(1);
+        }
+    }
+}