From 1e4acc80e0d05f9f83061ba268a7732b47c5807f Mon Sep 17 00:00:00 2001
From: Thayne McCombs <astrothayne@gmail.com>
Date: Sat, 27 Jan 2024 01:50:06 -0700
Subject: [PATCH] feat(kv): Add styling for key in default format

Make the key italic by default.
---
 examples/direct_logger.rs | 14 +++++++++++---
 src/fmt/kv.rs             | 25 +++++++++++++++++++++++--
 src/fmt/mod.rs            |  3 +++
 src/logger.rs             |  2 +-
 4 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/examples/direct_logger.rs b/examples/direct_logger.rs
index 4d7f39d0..397ccd8c 100644
--- a/examples/direct_logger.rs
+++ b/examples/direct_logger.rs
@@ -8,19 +8,27 @@ use env_logger::{Builder, WriteStyle};
 
 use log::{Level, LevelFilter, Log, MetadataBuilder, Record};
 
+#[cfg(feature = "unstable-kv")]
+static KVS: (&str, &str) = ("test", "something");
+
 fn record() -> Record<'static> {
     let error_metadata = MetadataBuilder::new()
         .target("myApp")
         .level(Level::Error)
         .build();
 
-    Record::builder()
+    let mut builder = Record::builder();
+    builder
         .metadata(error_metadata)
         .args(format_args!("Error!"))
         .line(Some(433))
         .file(Some("app.rs"))
-        .module_path(Some("server"))
-        .build()
+        .module_path(Some("server"));
+    #[cfg(feature = "unstable-kv")]
+    {
+        builder.key_values(&KVS);
+    }
+    builder.build()
 }
 
 fn main() {
diff --git a/src/fmt/kv.rs b/src/fmt/kv.rs
index bd2cae30..ecc362da 100644
--- a/src/fmt/kv.rs
+++ b/src/fmt/kv.rs
@@ -1,6 +1,7 @@
 use std::io::{self, Write};
 
-use super::Formatter;
+use super::{Formatter, StyledValue, WriteStyle};
+use anstyle::Style;
 use log::kv::{source::Source, Error, Key, Value, Visitor};
 
 /// Format function for serializing key/value pairs
@@ -41,7 +42,27 @@ impl<'a, 'kvs> Visitor<'kvs> for DefaultVisitor<'a> {
     fn visit_pair(&mut self, key: Key, value: Value<'kvs>) -> Result<(), Error> {
         // TODO: add styling
         // tracing-subscriber uses italic for the key and dimmed for the =
-        write!(self.0, " {}={}", key, value)?;
+        write!(self.0, " {}={}", self.style_key(key), value)?;
         Ok(())
     }
 }
+
+impl DefaultVisitor<'_> {
+    fn style_key<'k>(&self, text: Key<'k>) -> StyledValue<Key<'k>> {
+        #[cfg(feature = "color")]
+        {
+            StyledValue {
+                style: if self.0.write_style == WriteStyle::Never {
+                    Style::new()
+                } else {
+                    Style::new().italic()
+                },
+                value: text,
+            }
+        }
+        #[cfg(not(feature = "color"))]
+        {
+            key
+        }
+    }
+}
diff --git a/src/fmt/mod.rs b/src/fmt/mod.rs
index 55108cb2..ff32eb6a 100644
--- a/src/fmt/mod.rs
+++ b/src/fmt/mod.rs
@@ -292,6 +292,9 @@ impl<T: std::fmt::Display> std::fmt::Display for StyledValue<T> {
     }
 }
 
+#[cfg(not(feature = "color"))]
+type StyledValue<T> = T;
+
 /// The default format.
 ///
 /// This format needs to work with any combination of crate features.
diff --git a/src/logger.rs b/src/logger.rs
index 509c299b..ccc36154 100644
--- a/src/logger.rs
+++ b/src/logger.rs
@@ -321,7 +321,7 @@ impl Builder {
     /// The format function is expected to output the string directly to the `Formatter` so that
     /// implementations can use the [`std::fmt`] macros, similar to the main format function.
     ///
-    /// The default format uses a space to separte each key-value pair, with an "=" between
+    /// The default format uses a space to separate each key-value pair, with an "=" between
     /// the key and value.
     #[cfg(feature = "unstable-kv")]
     pub fn format_key_values<F: 'static>(&mut self, format: F) -> &mut Self