Added macro examples

src/macros.rs

@@ -50,6 +50,19 @@ macro_rules! log {
 /// Logs a message at the error level.
 ///
 /// Logging at this level is disabled if the `max_level_off` feature is present.
+///
+/// # Examples
+///
+/// ```rust
+/// # #[macro_use]
+/// # extern crate log;
+/// # fn main() {
+/// let (err_info, port) = ("No connection", 22);
+///
+/// error!("Error: {} on port {}", err_info, port);
+/// error!(target: "app_events", "App Error: {}, Port: {}", err_info, 22);
+/// # }
+/// ```
 #[macro_export]
 macro_rules! error {
     (target: $target:expr, $($arg:tt)*) => (
@@ -68,6 +81,19 @@ macro_rules! error {
 /// When building in release mode (i.e., without the `debug_assertions` option),
 /// logging at this level is also disabled if any of the following features are
 /// present: `release_max_level_off` or `max_level_error`.
+///
+/// # Examples
+///
+/// ```rust
+/// # #[macro_use]
+/// # extern crate log;
+/// # fn main() {
+/// let warn_description = "Invalid Input";
+///
+/// warn!("Warning! {}!", warn_description);
+/// warn!(target: "input_events", "App received warning: {}", warn_description);
+/// # }
+/// ```
 #[macro_export]
 macro_rules! warn {
     (target: $target:expr, $($arg:tt)*) => (
@@ -87,6 +113,21 @@ macro_rules! warn {
 /// logging at this level is also disabled if any of the following features are
 /// present: `release_max_level_off`, `release_max_level_error`, or
 /// `release_max_level_warn`.
+///
+/// # Examples
+///
+/// ```rust
+/// # #[macro_use]
+/// # extern crate log;
+/// # fn main() {
+/// # struct Connection { port: u32, speed: f32 }
+/// let conn_info = Connection { port: 40, speed: 3.20 };
+///
+/// info!("Connected to port {} at {} Mb/s", conn_info.port, conn_info.speed);
+/// info!(target: "connection_events", "Successfull connection, port: {}, speed: {}",
+///       conn_info.port, conn_info.speed);
+/// # }
+/// ```
 #[macro_export]
 macro_rules! info {
     (target: $target:expr, $($arg:tt)*) => (
@@ -107,6 +148,20 @@ macro_rules! info {
 /// logging at this level is also disabled if any of the following features are
 /// present: `release_max_level_off`, `release_max_level_error`,
 /// `release_max_level_warn`, or `release_max_level_info`.
+///
+/// # Examples
+///
+/// ```rust
+/// # #[macro_use]
+/// # extern crate log;
+/// # fn main() {
+/// # struct Position { x: f32, y: f32 }
+/// let pos = Position { x: 3.234, y: -1.223 };
+///
+/// debug!("New position: x: {}, y: {}", pos.x, pos.y);
+/// debug!(target: "app_events", "New position: x: {}, y: {}", pos.x, pos.y);
+/// # }
+/// ```
 #[macro_export]
 macro_rules! debug {
     (target: $target:expr, $($arg:tt)*) => (
@@ -128,6 +183,22 @@ macro_rules! debug {
 /// present: `release_max_level_off`, `release_max_level_error`,
 /// `release_max_level_warn`, `release_max_level_info`, or
 /// `release_max_level_debug`.
+///
+/// # Examples
+///
+/// ```rust
+/// # #[macro_use]
+/// # extern crate log;
+/// # fn main() {
+/// # struct Position { x: f32, y: f32 }
+/// let pos = Position { x: 3.234, y: -1.223 };
+///
+/// trace!("Position is: x: {}, y: {}", pos.x, pos.y);
+/// trace!(target: "app_events", "x is {} and y is {}",
+///        if pos.x >= 0.0 { "positive" } else { "negative" },
+///        if pos.y >= 0.0 { "positive" } else { "negative" });
+/// # }
+/// ```
 #[macro_export]
 macro_rules! trace {
     (target: $target:expr, $($arg:tt)*) => (