Initial commit

cog/src/main.rs

@@ -0,0 +1,47 @@
+use std::io::Write;
+
+fn main() -> std::io::Result<()> {
+    let mut last_success = true;
+    loop {
+        let mut line = String::new();
+
+        print!("{}$ ", if last_success { "".into() } else { "[error]" });
+        std::io::stdout().flush()?;
+        std::io::stdin().read_line(&mut line)?;
+
+        if !line.trim().is_empty() {
+            match exec_line(&line) {
+                Ok(success) => last_success = success,
+                Err(err) => {
+                    eprintln!("{err}");
+                }
+            }
+        }
+    }
+}
+
+fn exec_line(line: &str) -> Result<bool, String> {
+    let commands = shlex::split(line).ok_or_else(|| "invalid command".to_owned())?;
+    if commands.len() < 1 {
+        return Err("invalid command".to_owned());
+    }
+
+    let arg0 = &commands[0];
+
+    if arg0 == "exit" {
+        std::process::exit(0);
+    }
+
+    let mut cmd = std::process::Command::new(arg0);
+    cmd.args(&commands[1..]);
+
+    let mut cmd = cmd
+        .spawn()
+        .map_err(|err| format!("failed to spawn {arg0}: {err}"))?;
+
+    let result = cmd
+        .wait()
+        .map_err(|err| format!("failed to wait for {arg0}: {err}"))?;
+
+    Ok(result.success())
+}