add basic script repl

src/dev/console.rs

@@ -1,7 +1,7 @@
 use core::fmt;
 
 use lazy_static::lazy_static;
-use spin::Mutex;
+use spin::{Mutex, MutexGuard};
 
 use crate::hard::vga::{self, Vga};
 
@@ -17,12 +17,16 @@ macro_rules! println {
 }
 
 lazy_static! {
-	static ref Out: Mutex<Console> = Mutex::new(Console::init());
+	static ref OUT: Mutex<Console> = Mutex::new(Console::init());
+}
+
+pub fn out<'r>() -> MutexGuard<'r, Console> {
+	OUT.lock()
 }
 
 pub struct Console {
-	cursor: Cursor,
-	vga: Vga,
+	pub cursor: Cursor,
+	pub vga: Vga,
 }
 
 impl Console {
@@ -44,6 +48,11 @@ impl Console {
 			}
 		}
 	}
+
+	pub fn correct(&mut self) {
+		self.cursor.set_col((self.cursor.col().max(1) - 1));
+		self.vga.write_at(self.cursor.pos(), ' ');
+	}
 }
 
 struct Cursor {
@@ -67,14 +76,6 @@ impl Cursor {
 		(self.column, self.line)
 	}
 
-	pub fn set_line(&mut self, line: usize) {
-		self.line = line;
-	}
-
-	pub fn set_col(&mut self, col: usize) {
-		self.column = col;
-	}
-
 	pub fn line(&self) -> usize {
 		self.line
 	}
@@ -83,6 +84,18 @@ impl Cursor {
 		self.column
 	}
 
+	pub fn set_pos(&mut self, pos: (usize, usize)) {
+		(self.column, self.line) = pos;
+	}
+
+	pub fn set_line(&mut self, line: usize) {
+		self.line = line;
+	}
+
+	pub fn set_col(&mut self, col: usize) {
+		self.column = col;
+	}
+
 	pub fn progress(&mut self) {
 		self.column += 1;
 		if self.column < self.width {
@@ -113,6 +126,6 @@ pub fn print_args(args: fmt::Arguments) {
 	use core::fmt::Write;
 	use x86_64::instructions::interrupts;
 	interrupts::without_interrupts(|| {
-		Out.lock().write_fmt(args).unwrap();
+		OUT.lock().write_fmt(args).unwrap();
 	});
 }