feat(border): add border! macro for easy bitflag manipulation (#11)

Adds a `border!` macro that takes TOP, BOTTOM, LEFT, RIGHT, and ALL and
returns a Borders object. An empty `border!()` call returns
Borders::NONE

This is gated behind a `macros` feature flag to ensure short build
times. To enable, add the following to your `Cargo.toml`:

```toml
ratatui = { version = 0.21.0, features = ["macros"] }
```

Co-authored-by: C-Jameson <booksncode@gmail.com>

Cargo.toml

@@ -21,6 +21,7 @@ rust-version = "1.65.0"
 default = ["crossterm"]
 all-widgets = ["widget-calendar"]
 widget-calendar = ["time"]
+macros = []
 
 [package.metadata.docs.rs]
 all-features = true

Makefile.toml

@@ -118,15 +118,15 @@ args = [
 ]
 
 [tasks.test-crossterm]
-env = { TUI_FEATURES = "serde,crossterm,all-widgets" }
+env = { TUI_FEATURES = "serde,crossterm,all-widgets,macros" }
 run_task = "test"
 
 [tasks.test-termion]
-env = { TUI_FEATURES = "serde,termion,all-widgets" }
+env = { TUI_FEATURES = "serde,termion,all-widgets,macros" }
 run_task = "test"
 
 [tasks.test-termwiz]
-env = { TUI_FEATURES = "serde,termwiz,all-widgets" }
+env = { TUI_FEATURES = "serde,termwiz,all-widgets,macros" }
 run_task = "test"
 
 [tasks.test]

src/widgets/mod.rs

@@ -185,3 +185,41 @@ pub trait StatefulWidget {
     type State;
     fn render(self, area: Rect, buf: &mut Buffer, state: &mut Self::State);
 }
+
+/// Macro that constructs and returns a [`Borders`] object from TOP, BOTTOM, LEFT, RIGHT, NONE, and ALL.
+/// Internally it creates an empty `Borders` object and then inserts each bit flag specified
+/// into it using `Borders::insert()`.
+///
+/// ## Examples
+///
+///```
+/// # use tui::widgets::{Block, Borders};
+/// # use tui::style::{Style, Color};
+/// # use tui::border;
+///
+/// Block::default()
+///     //Construct a `Borders` object and use it in place
+///     .borders(border!(TOP, BOTTOM));
+///
+/// //`border!` can be called with any order of individual sides
+/// let bottom_first = border!(BOTTOM, LEFT, TOP);
+/// //with the ALL keyword which works as expected
+/// let all = border!(ALL);
+/// //or with nothing to return a `Borders::NONE' bitflag.
+/// let none = border!(NONE);
+///
+///```
+#[cfg(feature = "macros")]
+#[macro_export]
+macro_rules! border {
+    ( $($b:tt), +) => {{
+            let mut border = Borders::empty();
+            $(
+               border.insert(Borders::$b);
+            )*
+            border
+    }};
+    () =>{
+        Borders::NONE
+    }
+}

tests/border_macro.rs

@@ -0,0 +1,19 @@
+#![cfg(feature = "macros")]
+use ratatui::{border, widgets::Borders};
+
+#[test]
+fn border_empty_test() {
+    let empty = Borders::NONE;
+    assert_eq!(empty, border!());
+}
+#[test]
+fn border_all_test() {
+    let all = Borders::ALL;
+    assert_eq!(all, border!(ALL));
+    assert_eq!(all, border!(TOP, BOTTOM, LEFT, RIGHT));
+}
+#[test]
+fn border_left_right_test() {
+    let left_right = Borders::from_bits(Borders::LEFT.bits() | Borders::RIGHT.bits());
+    assert_eq!(left_right, Some(border!(RIGHT, LEFT)));
+}