feat: reading input + show prompt

src/main.rs

@@ -1,5 +1,6 @@
 use clap::Parser;
-
+use std::fs::File;
+use std::io::{self, BufRead, Write};
 
 #[derive(Parser, Debug)]
 #[command(version, about, long_about = None)]
@@ -9,12 +10,43 @@ struct Args {
     script: Option<String>,
 }
 
-fn main() {
+fn run(lines: io::Lines<io::BufReader<File>>) -> () {
+    for line in lines {
+        println!("Line: {}", line.unwrap());
+    }
+}
+
+fn run_file(script: String) -> Result<(), io::Error> {
+    let file = File::open(script)?;
+    run(io::BufReader::new(file).lines());
+
+    Ok(())
+}
+
+fn run_prompt() -> Result<(), io::Error> {
+    loop {
+        print!("> ");
+        io::stdout().flush()?;
+
+        let mut buffer = String::new();
+        io::stdin().read_line(&mut buffer)?;
+        if buffer.len() == 0 {
+            break;
+        }
+        println!("input: '{}', {}", buffer, buffer.len());
+    }
+
+    Ok(())
+}
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let args = Args::parse();
 
     if let Some(script) = args.script {
-        println!("Run script! {}", script);
+        run_file(script)?;
     } else {
-        println!("Run Prompt");
+        run_prompt()?;
     }
+
+    Ok(())
 }