Implemented prompt expansion

src/shellenv/meta.rs

@@ -1,14 +1,32 @@
+use std::time::{Duration, Instant};
+
 #[derive(Clone,Debug)]
 pub struct MetaTab {
+	timer_start: Option<Instant>,
+	last_runtime: Option<Duration>,
 	last_status: i32
 }
 
 impl MetaTab {
 	pub fn new() -> Self {
 		Self {
+			timer_start: None,
+			last_runtime: None,
 			last_status: 0
 		}
 	}
+	pub fn start_timer(&mut self) {
+		self.timer_start = Some(Instant::now())
+	}
+	pub fn stop_timer(&mut self) {
+		let timer_start = self.timer_start.take();
+		if let Some(instant) = timer_start {
+			self.last_runtime = Some(instant.elapsed())
+		}
+	}
+	pub fn get_runtime(&self) -> Option<Duration> {
+		self.last_runtime
+	}
 	pub fn set_status(&mut self, code: i32) {
 		self.last_status = code
 	}