5 files changed, 34 insertions, 6 deletions
diff --git a/niri-config/src/appearance.rs b/niri-config/src/appearance.rs
index e5efc4be..cc698ef6 100644
--- a/niri-config/src/appearance.rs
+++ b/niri-config/src/appearance.rs
@@ -5,6 +5,7 @@ use knuffel::errors::DecodeError;
 use miette::{miette, IntoDiagnostic as _};
 use smithay::backend::renderer::Color32F;
 
+use crate::utils::MergeWith;
 use crate::FloatOrInt;
 
 pub const DEFAULT_BACKGROUND_COLOR: Color = Color::from_array_unpremul([0.25, 0.25, 0.25, 1.]);
@@ -563,8 +564,8 @@ pub struct TabIndicatorRule {
     pub urgent_gradient: Option<Gradient>,
 }
 
-impl BorderRule {
-    pub fn merge_with(&mut self, other: &Self) {
+impl MergeWith<Self> for BorderRule {
+    fn merge_with(&mut self, other: &Self) {
         if other.off {
             self.off = true;
             self.on = false;
@@ -600,7 +601,9 @@ impl BorderRule {
             self.urgent_gradient = Some(x);
         }
     }
+}
 
+impl BorderRule {
     pub fn resolve_against(&self, mut config: Border) -> Border {
         config.off |= self.off;
         if self.on {
@@ -636,8 +639,8 @@ impl BorderRule {
     }
 }
 
-impl ShadowRule {
-    pub fn merge_with(&mut self, other: &Self) {
+impl MergeWith<Self> for ShadowRule {
+    fn merge_with(&mut self, other: &Self) {
         if other.off {
             self.off = true;
             self.on = false;
@@ -667,7 +670,9 @@ impl ShadowRule {
             self.inactive_color = Some(x);
         }
     }
+}
 
+impl ShadowRule {
     pub fn resolve_against(&self, mut config: Shadow) -> Shadow {
         config.on |= self.on;
         if self.off {
@@ -697,8 +702,8 @@ impl ShadowRule {
     }
 }
 
-impl TabIndicatorRule {
-    pub fn merge_with(&mut self, other: &Self) {
+impl MergeWith<Self> for TabIndicatorRule {
+    fn merge_with(&mut self, other: &Self) {
         if let Some(x) = other.active_color {
             self.active_color = Some(x);
             self.active_gradient = None;
diff --git a/niri-config/src/utils.rs b/niri-config/src/utils.rs
index 77baac5e..e2a24901 100644
--- a/niri-config/src/utils.rs
+++ b/niri-config/src/utils.rs
@@ -4,6 +4,9 @@ use knuffel::errors::DecodeError;
 use miette::miette;
 use regex::Regex;
 
+mod merge_with;
+pub use merge_with::*;
+
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub struct Percent(pub f64);
 
diff --git a/niri-config/src/utils/merge_with.rs b/niri-config/src/utils/merge_with.rs
new file mode 100644
index 00000000..857e2146
--- /dev/null
+++ b/niri-config/src/utils/merge_with.rs
@@ -0,0 +1,18 @@
+pub trait MergeWith<T> {
+    fn merge_with(&mut self, part: &T);
+
+    fn merged_with(mut self, part: &T) -> Self
+    where
+        Self: Sized,
+    {
+        self.merge_with(part);
+        self
+    }
+
+    fn from_part(part: &T) -> Self
+    where
+        Self: Default + Sized,
+    {
+        Self::default().merged_with(part)
+    }
+}
diff --git a/src/layer/mod.rs b/src/layer/mod.rs
index 2ff8b7ca..19a091c1 100644
--- a/src/layer/mod.rs
+++ b/src/layer/mod.rs
@@ -1,4 +1,5 @@
 use niri_config::layer_rule::{LayerRule, Match};
+use niri_config::utils::MergeWith as _;
 use niri_config::{BlockOutFrom, CornerRadius, ShadowRule};
 use smithay::desktop::LayerSurface;
 
diff --git a/src/window/mod.rs b/src/window/mod.rs
index b07b80d8..c65fa535 100644
--- a/src/window/mod.rs
+++ b/src/window/mod.rs
@@ -1,5 +1,6 @@
 use std::cmp::{max, min};
 
+use niri_config::utils::MergeWith as _;
 use niri_config::window_rule::{Match, WindowRule};
 use niri_config::{
     BlockOutFrom, BorderRule, CornerRadius, FloatingPosition, PresetSize, ShadowRule,