Merge #383

383: Macros: Add dbg r=jounathaen a=mkroening



Co-authored-by: Martin Kröning <m.kroening@hotmail.de>

src/macros.rs

@@ -26,6 +26,34 @@ macro_rules! println {
 	($($arg:tt)+) => (print!("{}\n", ::core::format_args!($($arg)+)));
 }
 
+/// Prints and returns the value of a given expression for quick and dirty
+/// debugging.
+// Copied from std/macros.rs
+#[macro_export]
+macro_rules! dbg {
+    // NOTE: We cannot use `concat!` to make a static string as a format argument
+    // of `eprintln!` because `file!` could contain a `{` or
+    // `$val` expression could be a block (`{ .. }`), in which case the `eprintln!`
+    // will be malformed.
+    () => {
+        $crate::println!("[{}:{}]", ::core::file!(), ::core::line!())
+    };
+    ($val:expr $(,)?) => {
+        // Use of `match` here is intentional because it affects the lifetimes
+        // of temporaries - https://stackoverflow.com/a/48732525/1063961
+        match $val {
+            tmp => {
+                $crate::println!("[{}:{}] {} = {:#?}",
+                    ::core::file!(), ::core::line!(), ::core::stringify!($val), &tmp);
+                tmp
+            }
+        }
+    };
+    ($($val:expr),+ $(,)?) => {
+        ($($crate::dbg!($val)),+,)
+    };
+}
+
 /// Runs `f` on the kernel stack.
 ///
 /// All arguments and return values have to fit into registers: