From 6ac15000f306fbc719be8970bab720f42b63a5a0 Mon Sep 17 00:00:00 2001
From: a-kenji <aks.kenji@protonmail.com>
Date: Sat, 1 Jul 2023 14:17:36 +0200
Subject: [PATCH] feat(style): allow Modifiers add/remove in const

Allows Modifiers to be added or removed from `Style` in a const context.
This can be used in the following way:

```
const DEFAULT_MODIFIER: Modifier = Modifier::BOLD.union(Modifier::ITALIC);
const DEFAULT_STYLE: Style = Style::new()
.fg(Color::Red).bg(Color::Black).add_modifier(DEFAULT_MODIFIER);
```
---
 src/style.rs | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/src/style.rs b/src/style.rs
index 56f2a41ee..c96e18aaa 100644
--- a/src/style.rs
+++ b/src/style.rs
@@ -245,9 +245,9 @@ impl Style {
     /// assert_eq!(patched.add_modifier, Modifier::BOLD | Modifier::ITALIC);
     /// assert_eq!(patched.sub_modifier, Modifier::empty());
     /// ```
-    pub fn add_modifier(mut self, modifier: Modifier) -> Style {
-        self.sub_modifier.remove(modifier);
-        self.add_modifier.insert(modifier);
+    pub const fn add_modifier(mut self, modifier: Modifier) -> Style {
+        self.sub_modifier = self.sub_modifier.difference(modifier);
+        self.add_modifier = self.add_modifier.union(modifier);
         self
     }
 
@@ -265,9 +265,9 @@ impl Style {
     /// assert_eq!(patched.add_modifier, Modifier::BOLD);
     /// assert_eq!(patched.sub_modifier, Modifier::ITALIC);
     /// ```
-    pub fn remove_modifier(mut self, modifier: Modifier) -> Style {
-        self.add_modifier.remove(modifier);
-        self.sub_modifier.insert(modifier);
+    pub const fn remove_modifier(mut self, modifier: Modifier) -> Style {
+        self.add_modifier = self.add_modifier.difference(modifier);
+        self.sub_modifier = self.sub_modifier.union(modifier);
         self
     }
 
@@ -500,9 +500,31 @@ mod tests {
             );
         }
     }
+
     #[test]
     fn style_can_be_const() {
-        const _DEFAULT_STYLE: Style = Style::new().fg(Color::Red).bg(Color::Black);
+        const RED: Color = Color::Red;
+        const BLACK: Color = Color::Black;
+        const BOLD: Modifier = Modifier::BOLD;
+        const ITALIC: Modifier = Modifier::ITALIC;
+
         const _RESET: Style = Style::reset();
+        const _RED_FG: Style = Style::new().fg(RED);
+        const _BLACK_BG: Style = Style::new().bg(BLACK);
+        const _ADD_BOLD: Style = Style::new().add_modifier(BOLD);
+        const _REMOVE_ITALIC: Style = Style::new().remove_modifier(ITALIC);
+        const ALL: Style = Style::new()
+            .fg(RED)
+            .bg(BLACK)
+            .add_modifier(BOLD)
+            .remove_modifier(ITALIC);
+        assert_eq!(
+            ALL,
+            Style::new()
+                .fg(Color::Red)
+                .bg(Color::Black)
+                .add_modifier(Modifier::BOLD)
+                .remove_modifier(Modifier::ITALIC)
+        )
     }
 }