support field shorthand in macros

README.md

@@ -116,7 +116,7 @@ pub fn shave_the_yak(yak: &mut Yak) {
                 break;
             }
             Err(err) => {
-                warn!(err:error = err; "Unable to locate a razor, retrying");
+                warn!(err:err; "Unable to locate a razor, retrying");
             }
         }
     }

src/kv/mod.rs

@@ -29,6 +29,15 @@
 //! info!(a = 1; "Something of interest");
 //! ```
 //!
+//! Key-values support the same shorthand identifer syntax as `format_args`:
+//!
+//! ```
+//! # use log::info;
+//! let a = 1;
+//!
+//! info!(a; "Something of interest");
+//! ```
+//!
 //! Values are capturing using the [`ToValue`] trait by default. To capture a value
 //! using a different trait implementation, use a modifier after its key. Here's how
 //! the same example can capture `a` using its `Debug` implementation instead:
@@ -44,7 +53,7 @@
 //! - `:debug` will capture the value using `Debug`.
 //! - `:%` will capture the value using `Display`.
 //! - `:display` will capture the value using `Display`.
-//! - `:error` will capture the value using `std::error::Error` (requires the `kv_std` feature).
+//! - `:err` will capture the value using `std::error::Error` (requires the `kv_std` feature).
 //! - `:sval` will capture the value using `sval::Value` (requires the `kv_sval` feature).
 //! - `:serde` will capture the value using `serde::Serialize` (requires the `kv_serde` feature).
 //!

src/kv/value.rs

@@ -1142,7 +1142,7 @@ macro_rules! as_display {
 
 /// Get a value from an error.
 #[cfg(feature = "kv_unstable_std")]
-#[deprecated(note = "use the `key:error = value` macro syntax instead")]
+#[deprecated(note = "use the `key:err = value` macro syntax instead")]
 #[macro_export]
 macro_rules! as_error {
     ($capture:expr) => {

src/lib.rs

@@ -112,7 +112,7 @@
 //!                 break;
 //!             }
 //!             Err(err) => {
-//!                 warn!(err:error = err; "Unable to locate a razor, retrying");
+//!                 warn!(err:err; "Unable to locate a razor, retrying");
 //!             }
 //!         }
 //!     }

src/macros.rs

@@ -30,15 +30,15 @@
 #[macro_export]
 macro_rules! log {
     // log!(target: "my_target", Level::Info, key1:? = 42, key2 = true; "a {} event", "log");
-    (target: $target:expr, $lvl:expr, $($key:tt $(:$capture:tt)? = $value:expr),+; $($arg:tt)+) => ({
+    (target: $target:expr, $lvl:expr, $($key:tt $(:$capture:tt)? $(= $value:expr)?),+; $($arg:tt)+) => ({
         let lvl = $lvl;
         if lvl <= $crate::STATIC_MAX_LEVEL && lvl <= $crate::max_level() {
             $crate::__private_api::log::<&_>(
                 $crate::__private_api::format_args!($($arg)+),
                 lvl,
                 &($target, $crate::__private_api::module_path!(), $crate::__private_api::file!()),
                 $crate::__private_api::line!(),
-                &[$(($crate::__log_key!($key), $crate::__log_value!(($value)$(:$capture)*))),+]
+                &[$(($crate::__log_key!($key), $crate::__log_value!($key $(:$capture)* = $($value)*))),+]
             );
         }
     });
@@ -256,10 +256,19 @@ macro_rules! __log_key {
 #[macro_export]
 #[cfg(feature = "kv")]
 macro_rules! __log_value {
-    // Default
-    (($args:expr)) => {
+    // Entrypoint
+    ($key:tt = $args:expr) => {
         $crate::__log_value!(($args):value)
     };
+    ($key:tt :$capture:tt = $args:expr) => {
+        $crate::__log_value!(($args):$capture)
+    };
+    ($key:ident =) => {
+        $crate::__log_value!(($key):value)
+    };
+    ($key:ident :$capture:tt =) => {
+        $crate::__log_value!(($key):$capture)
+    };
     // ToValue
     (($args:expr):value) => {
         $crate::__private_api::capture_to_value(&&$args)

tests/macros.rs

@@ -165,6 +165,15 @@ fn kv_named_args() {
     all_log_macros!(cat_1 = "chashu", cat_2 = "nori", cat_count = 2; "hello {world}", world = "world");
 }
 
+#[test]
+#[cfg(feature = "kv")]
+fn kv_ident() {
+    let cat_1 = "chashu";
+    let cat_2 = "nori";
+
+    all_log_macros!(cat_1, cat_2:%, cat_count = 2; "hello {world}", world = "world");
+}
+
 #[test]
 #[cfg(feature = "kv")]
 fn kv_expr_context() {
@@ -274,7 +283,7 @@ fn kv_display() {
 #[cfg(feature = "kv_std")]
 fn kv_error() {
     all_log_macros!(
-        a:error = std::io::Error::new(std::io::ErrorKind::Other, "an error");
+        a:err = std::io::Error::new(std::io::ErrorKind::Other, "an error");
         "hello world"
     );
 }