From e298259dd5d8281367303e50c72ce857a03c8f8a Mon Sep 17 00:00:00 2001
From: tigregalis <anak.harimau@gmail.com>
Date: Mon, 8 May 2023 18:11:36 +0800
Subject: [PATCH 1/4] introduce `BidiParagraphs` iterator

---
 src/bidi_para.rs | 39 +++++++++++++++++++++++++++++++++++++++
 src/lib.rs       |  3 +++
 2 files changed, 42 insertions(+)
 create mode 100644 src/bidi_para.rs

diff --git a/src/bidi_para.rs b/src/bidi_para.rs
new file mode 100644
index 0000000..461665e
--- /dev/null
+++ b/src/bidi_para.rs
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use unicode_bidi::{bidi_class, BidiClass, BidiInfo, ParagraphInfo};
+
+/// An iterator over the paragraphs in the input text.
+/// It is equivalent to [`core::str::Lines`] but follows `unicode-bidi` behaviour.
+pub struct BidiParagraphs<'text> {
+    text: &'text str,
+    info: std::vec::IntoIter<ParagraphInfo>,
+}
+
+impl<'text> BidiParagraphs<'text> {
+    /// Create an iterator to split the input text into paragraphs
+    /// in accordance with `unicode-bidi` behaviour.
+    pub fn new(text: &'text str) -> Self {
+        let info = BidiInfo::new(text, None);
+        let info = info.paragraphs.into_iter();
+        Self { text, info }
+    }
+}
+
+impl<'text> Iterator for BidiParagraphs<'text> {
+    type Item = &'text str;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let para = self.info.next()?;
+        let paragraph = &self.text[para.range];
+        // `para.range` includes the newline that splits the line, so remove it if present
+        let mut char_indices = paragraph.char_indices();
+        if let Some(i) = char_indices.next_back().and_then(|(i, c)| {
+            // `BidiClass::B` is a Paragraph_Separator (various newline characters)
+            (bidi_class(c) == BidiClass::B).then_some(i)
+        }) {
+            Some(&paragraph[0..i])
+        } else {
+            Some(paragraph)
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index f4b700e..a07eecf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -95,6 +95,9 @@ extern crate alloc;
 pub use self::attrs::*;
 mod attrs;
 
+pub use self::bidi_para::*;
+mod bidi_para;
+
 pub use self::buffer::*;
 mod buffer;
 

From 6e336ad1cded98c3b4eeabb0521ad7048216d226 Mon Sep 17 00:00:00 2001
From: tigregalis <anak.harimau@gmail.com>
Date: Mon, 8 May 2023 18:12:36 +0800
Subject: [PATCH 2/4] replace use of `str::lines` with `BidiParagraphs`

---
 examples/editor-test/src/main.rs | 5 +++--
 src/buffer.rs                    | 6 +++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/examples/editor-test/src/main.rs b/examples/editor-test/src/main.rs
index ea859d5..12318ce 100644
--- a/examples/editor-test/src/main.rs
+++ b/examples/editor-test/src/main.rs
@@ -1,7 +1,8 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
 use cosmic_text::{
-    Action, BorrowedWithFontSystem, Buffer, Color, Edit, Editor, FontSystem, Metrics, SwashCache,
+    Action, BidiParagraphs, BorrowedWithFontSystem, Buffer, Color, Edit, Editor, FontSystem,
+    Metrics, SwashCache,
 };
 use orbclient::{EventOption, Renderer, Window, WindowFlag};
 use std::{env, fs, process, time::Instant};
@@ -84,7 +85,7 @@ fn main() {
     let test_start = Instant::now();
 
     //TODO: support bidi
-    for line in text.lines() {
+    for line in BidiParagraphs::new(&text) {
         log::debug!("Line {:?}", line);
 
         for grapheme in line.graphemes(true) {
diff --git a/src/buffer.rs b/src/buffer.rs
index 7ddd20d..0807911 100644
--- a/src/buffer.rs
+++ b/src/buffer.rs
@@ -9,8 +9,8 @@ use core::{cmp, fmt};
 use unicode_segmentation::UnicodeSegmentation;
 
 use crate::{
-    Attrs, AttrsList, BorrowedWithFontSystem, BufferLine, Color, FontSystem, LayoutGlyph,
-    LayoutLine, ShapeLine, Shaping, Wrap,
+    Attrs, AttrsList, BidiParagraphs, BorrowedWithFontSystem, BufferLine, Color, FontSystem,
+    LayoutGlyph, LayoutLine, ShapeLine, Shaping, Wrap,
 };
 
 /// Current cursor location
@@ -580,7 +580,7 @@ impl Buffer {
         shaping: Shaping,
     ) {
         self.lines.clear();
-        for line in text.lines() {
+        for line in BidiParagraphs::new(text) {
             self.lines.push(BufferLine::new(
                 line.to_string(),
                 AttrsList::new(attrs),

From 053efa77b66cbf6ae3a6d36ba9a7252af801593b Mon Sep 17 00:00:00 2001
From: tigregalis <anak.harimau@gmail.com>
Date: Mon, 8 May 2023 18:24:38 +0800
Subject: [PATCH 3/4] remove todo comment

---
 examples/editor-test/src/main.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/examples/editor-test/src/main.rs b/examples/editor-test/src/main.rs
index 12318ce..8f3effe 100644
--- a/examples/editor-test/src/main.rs
+++ b/examples/editor-test/src/main.rs
@@ -84,7 +84,6 @@ fn main() {
 
     let test_start = Instant::now();
 
-    //TODO: support bidi
     for line in BidiParagraphs::new(&text) {
         log::debug!("Line {:?}", line);
 

From 5ab509ebaa3bce7c41bd1111a94c462297883cda Mon Sep 17 00:00:00 2001
From: tigregalis <anak.harimau@gmail.com>
Date: Thu, 11 May 2023 17:14:52 +0800
Subject: [PATCH 4/4] use `alloc::vec` instead of `std::vec`

---
 src/bidi_para.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/bidi_para.rs b/src/bidi_para.rs
index 461665e..fd50d0d 100644
--- a/src/bidi_para.rs
+++ b/src/bidi_para.rs
@@ -6,7 +6,7 @@ use unicode_bidi::{bidi_class, BidiClass, BidiInfo, ParagraphInfo};
 /// It is equivalent to [`core::str::Lines`] but follows `unicode-bidi` behaviour.
 pub struct BidiParagraphs<'text> {
     text: &'text str,
-    info: std::vec::IntoIter<ParagraphInfo>,
+    info: alloc::vec::IntoIter<ParagraphInfo>,
 }
 
 impl<'text> BidiParagraphs<'text> {