1 files changed, 16 insertions, 7 deletions
diff --git a/src/run/mod.rs b/src/run/mod.rs
index 8c629b0..a27812f 100644
--- a/src/run/mod.rs
+++ b/src/run/mod.rs
@@ -256,22 +256,31 @@ pub fn run(se: &mut Session, cmd: Vec<u8>) {
     let _ = std::io::stdout().lock().flush();
 }
 
+#[derive(Debug)]
+enum BuiltinError {
+    IO(std::io::Error),
+    Exit(i32),
+}
+
+impl From<std::io::Error> for BuiltinError {
+    fn from(value: std::io::Error) -> Self {
+        Self::IO(value)
+    }
+}
+
+type BuiltinResult = Result<(), BuiltinError>;
+
 #[allow(unused_variables)]
 pub trait Builtin: Send + Sync {
     fn name(&self) -> &str;
 
-    /// quick synchronous call, `cd` for example
-    fn mod_session(&self, session: &mut Session, args: &[BString]) {}
-
-    /// potentially long, pipelineable thread, builtin `cat` for example
     fn io(
         &self,
+        session: Arc<Mutex<Session>>,
         args: &[BString],
         stdin: &mut dyn Read,
         stdout: &mut dyn Write,
-    ) -> std::io::Result<()> {
-        Ok(())
-    }
+    ) -> BuiltinResult;
 }
 
 const BUILTINS: &[&'static dyn Builtin] = &[