Implement print!/println! macros

src/main.rs

@@ -7,15 +7,7 @@ mod vga_buffer;
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
-    use core::fmt::Write;
+    println!("Hello World{}", "!");
-    vga_buffer::WRITER.lock().write_str("Hello again").unwrap();
-    write!(
-        vga_buffer::WRITER.lock(),
-        ", some numbers: {} {}",
-        42,
-        1.337
-    )
-    .unwrap();
 
     loop {}
 }

src/vga_buffer.rs

@@ -123,3 +123,20 @@ impl fmt::Write for Writer {
         Ok(())
     }
 }
+
+#[macro_export]
+macro_rules! print {
+    ($($arg:tt)*) => ($crate::vga_buffer::_print(format_args!($($arg)*)));
+}
+
+#[macro_export]
+macro_rules! println {
+    () => ($crate::print!("\n"));
+    ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
+}
+
+#[doc(hidden)]
+pub fn _print(args: fmt::Arguments) {
+    use core::fmt::Write;
+    WRITER.lock().write_fmt(args).unwrap();
+}