Add key-values to the macros

src/lib.rs

@@ -1452,10 +1452,39 @@ pub fn logger() -> &'static dyn Log {
 
 // WARNING: this is not part of the crate's public API and is subject to change at any time
 #[doc(hidden)]
+#[cfg(not(feature = "kv_unstable"))]
 pub fn __private_api_log(
     args: fmt::Arguments,
     level: Level,
     &(target, module_path, file, line): &(&str, &'static str, &'static str, u32),
+    kvs: Option<&[(&str, &str)]>,
+) {
+    if kvs.is_some() {
+        panic!(
+            "key-value support is experimental and must be enabled using the `kv_unstable` feature"
+        )
+    }
+
+    logger().log(
+        &Record::builder()
+            .args(args)
+            .level(level)
+            .target(target)
+            .module_path_static(Some(module_path))
+            .file_static(Some(file))
+            .line(Some(line))
+            .build(),
+    );
+}
+
+// WARNING: this is not part of the crate's public API and is subject to change at any time
+#[doc(hidden)]
+#[cfg(feature = "kv_unstable")]
+pub fn __private_api_log(
+    args: fmt::Arguments,
+    level: Level,
+    &(target, module_path, file, line): &(&str, &'static str, &'static str, u32),
+    kvs: Option<&[(&str, &dyn kv::ToValue)]>,
 ) {
     logger().log(
         &Record::builder()
@@ -1465,6 +1494,7 @@ pub fn __private_api_log(
             .module_path_static(Some(module_path))
             .file_static(Some(file))
             .line(Some(line))
+            .key_values(&kvs)
             .build(),
     );
 }

src/macros.rs

@@ -29,13 +29,25 @@
 /// ```
 #[macro_export(local_inner_macros)]
 macro_rules! log {
+    (target: $target:expr, $lvl:expr, $($key:ident = $value:expr),* ; $fmt:expr,  $($arg:tt)+) => ({
+        let lvl = $lvl;
+        if lvl <= $crate::STATIC_MAX_LEVEL && lvl <= $crate::max_level() {
+            $crate::__private_api_log(
+                __log_format_args!($fmt, $($arg)+),
+                lvl,
+                &($target, __log_module_path!(), __log_file!(), __log_line!()),
+                Some(&[$((__log_stringify!($key), &$value)),*])
+            );
+        }
+    });
     (target: $target:expr, $lvl:expr, $($arg:tt)+) => ({
         let lvl = $lvl;
         if lvl <= $crate::STATIC_MAX_LEVEL && lvl <= $crate::max_level() {
             $crate::__private_api_log(
                 __log_format_args!($($arg)+),
                 lvl,
                 &($target, __log_module_path!(), __log_file!(), __log_line!()),
+                None,
             );
         }
     });
@@ -248,3 +260,11 @@ macro_rules! __log_line {
         line!()
     };
 }
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! __log_stringify {
+    ($($args:tt)*) => {
+        stringify!($($args)*)
+    };
+}

tests/macros.rs

@@ -35,3 +35,21 @@ fn with_named_args() {
     info!("hello {cats}", cats = cats,);
     info!("hello {cats}", cats = cats,);
 }
+
+#[test]
+#[cfg(feature = "kv_unstable")]
+fn kv() {
+    info!(cat_1 = "chashu", cat_2 = "nori"; "hello {}", "cats");
+    info!(target: "my_target", cat_1 = "chashu", cat_2 = "nori"; "hello {}", "cats");
+    log!(target: "my_target", log::Level::Warn, cat_1 = "chashu", cat_2 = "nori"; "hello {}", "cats");
+}
+
+#[test]
+#[cfg(feature = "kv_unstable")]
+fn kv_expr_context() {
+    match "chashu" {
+        cat_1 => {
+            info!(target: "target", cat_1 = cat_1, cat_2 = "nori"; "hello {}", "cats")
+        }
+    };
+}