vikingowl
498e6e61b6
- Introduce new `owlen-markdown` crate that converts Markdown strings to `ratatui::Text` with headings, lists, bold/italic, and inline code. - Add `render_markdown` config option (default true) and expose it via `app.render_markdown_enabled()`. - Implement `:markdown [on|off]` command to toggle markdown rendering. - Update help overlay to document the new markdown toggle. - Adjust UI rendering to conditionally apply markdown styling based on the markdown flag and code mode. - Wire the new crate into `owlen-tui` Cargo.toml.
271 lines
8.5 KiB
Rust
271 lines
8.5 KiB
Rust
use ratatui::prelude::*;
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use ratatui::text::{Line, Span, Text};
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use unicode_width::UnicodeWidthStr;
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/// Convert a markdown string into a `ratatui::Text`.
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///
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/// This lightweight renderer supports common constructs (headings, lists, bold,
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/// italics, and inline code) and is designed to keep dependencies minimal for
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/// the OWLEN project.
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pub fn from_str(input: &str) -> Text<'static> {
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let mut lines = Vec::new();
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let mut in_code_block = false;
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for raw_line in input.lines() {
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let line = raw_line.trim_end_matches('\r');
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let trimmed = line.trim_start();
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let indent = &line[..line.len() - trimmed.len()];
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if trimmed.starts_with("```") {
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in_code_block = !in_code_block;
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continue;
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}
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if in_code_block {
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let mut spans = Vec::new();
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if !indent.is_empty() {
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spans.push(Span::raw(indent.to_string()));
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}
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spans.push(Span::styled(
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trimmed.to_string(),
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Style::default()
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.fg(Color::LightYellow)
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.add_modifier(Modifier::DIM),
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));
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lines.push(Line::from(spans));
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continue;
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}
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if trimmed.is_empty() {
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lines.push(Line::from(Vec::<Span<'static>>::new()));
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continue;
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}
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if trimmed.starts_with('#') {
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let level = trimmed.chars().take_while(|c| *c == '#').count().min(6);
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let content = trimmed[level..].trim_start();
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let mut style = Style::default().add_modifier(Modifier::BOLD);
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style = match level {
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1 => style.fg(Color::LightCyan),
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2 => style.fg(Color::Cyan),
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_ => style.fg(Color::LightBlue),
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};
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let mut spans = Vec::new();
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if !indent.is_empty() {
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spans.push(Span::raw(indent.to_string()));
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}
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spans.push(Span::styled(content.to_string(), style));
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lines.push(Line::from(spans));
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continue;
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}
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if let Some(rest) = trimmed.strip_prefix("- ") {
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let mut spans = Vec::new();
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if !indent.is_empty() {
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spans.push(Span::raw(indent.to_string()));
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}
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spans.push(Span::styled(
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"• ".to_string(),
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Style::default().fg(Color::LightGreen),
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));
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spans.extend(parse_inline(rest));
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lines.push(Line::from(spans));
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continue;
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}
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if let Some(rest) = trimmed.strip_prefix("* ") {
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let mut spans = Vec::new();
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if !indent.is_empty() {
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spans.push(Span::raw(indent.to_string()));
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}
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spans.push(Span::styled(
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"• ".to_string(),
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Style::default().fg(Color::LightGreen),
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));
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spans.extend(parse_inline(rest));
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lines.push(Line::from(spans));
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continue;
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}
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if let Some((number, rest)) = parse_ordered_item(trimmed) {
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let mut spans = Vec::new();
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if !indent.is_empty() {
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spans.push(Span::raw(indent.to_string()));
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}
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spans.push(Span::styled(
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format!("{number}. "),
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Style::default().fg(Color::LightGreen),
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));
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spans.extend(parse_inline(rest));
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lines.push(Line::from(spans));
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continue;
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}
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let mut spans = Vec::new();
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if !indent.is_empty() {
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spans.push(Span::raw(indent.to_string()));
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}
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spans.extend(parse_inline(trimmed));
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lines.push(Line::from(spans));
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}
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if input.is_empty() {
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lines.push(Line::from(Vec::<Span<'static>>::new()));
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}
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Text::from(lines)
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}
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fn parse_ordered_item(line: &str) -> Option<(u32, &str)> {
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let mut parts = line.splitn(2, '.');
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let number = parts.next()?.trim();
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let rest = parts.next()?;
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if number.chars().all(|c| c.is_ascii_digit()) {
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let value = number.parse().ok()?;
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let rest = rest.trim_start();
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Some((value, rest))
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} else {
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None
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}
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}
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fn parse_inline(text: &str) -> Vec<Span<'static>> {
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let mut spans = Vec::new();
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let bytes = text.as_bytes();
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let mut i = 0;
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let len = bytes.len();
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let mut plain_start = 0;
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while i < len {
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if bytes[i] == b'`' {
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if let Some(offset) = text[i + 1..].find('`') {
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if i > plain_start {
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spans.push(Span::raw(text[plain_start..i].to_string()));
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}
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let content = &text[i + 1..i + 1 + offset];
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spans.push(Span::styled(
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content.to_string(),
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Style::default()
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.fg(Color::LightYellow)
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.add_modifier(Modifier::BOLD),
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));
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i += offset + 2;
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plain_start = i;
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continue;
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} else {
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break;
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}
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}
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if bytes[i] == b'*' {
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if i + 1 < len && bytes[i + 1] == b'*' {
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if let Some(offset) = text[i + 2..].find("**") {
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if i > plain_start {
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spans.push(Span::raw(text[plain_start..i].to_string()));
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}
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let content = &text[i + 2..i + 2 + offset];
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spans.push(Span::styled(
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content.to_string(),
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Style::default().add_modifier(Modifier::BOLD),
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));
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i += offset + 4;
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plain_start = i;
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continue;
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}
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} else if let Some(offset) = text[i + 1..].find('*') {
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if i > plain_start {
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spans.push(Span::raw(text[plain_start..i].to_string()));
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}
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let content = &text[i + 1..i + 1 + offset];
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spans.push(Span::styled(
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content.to_string(),
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Style::default().add_modifier(Modifier::ITALIC),
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));
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i += offset + 2;
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plain_start = i;
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continue;
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}
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}
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if bytes[i] == b'_' {
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if i + 1 < len && bytes[i + 1] == b'_' {
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if let Some(offset) = text[i + 2..].find("__") {
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if i > plain_start {
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spans.push(Span::raw(text[plain_start..i].to_string()));
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}
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let content = &text[i + 2..i + 2 + offset];
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spans.push(Span::styled(
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content.to_string(),
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Style::default().add_modifier(Modifier::BOLD),
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));
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i += offset + 4;
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plain_start = i;
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continue;
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}
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} else if let Some(offset) = text[i + 1..].find('_') {
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if i > plain_start {
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spans.push(Span::raw(text[plain_start..i].to_string()));
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}
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let content = &text[i + 1..i + 1 + offset];
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spans.push(Span::styled(
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content.to_string(),
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Style::default().add_modifier(Modifier::ITALIC),
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));
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i += offset + 2;
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plain_start = i;
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continue;
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}
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}
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i += 1;
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}
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if plain_start < len {
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spans.push(Span::raw(text[plain_start..].to_string()));
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}
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if spans.is_empty() {
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spans.push(Span::raw(String::new()));
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}
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spans
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}
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#[allow(dead_code)]
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fn visual_length(spans: &[Span<'_>]) -> usize {
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spans
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.iter()
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.map(|span| UnicodeWidthStr::width(span.content.as_ref()))
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.sum()
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn headings_are_bold() {
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let text = from_str("# Heading");
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assert_eq!(text.lines.len(), 1);
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let line = &text.lines[0];
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assert!(
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line.spans
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.iter()
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.any(|span| span.style.contains(Modifier::BOLD))
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);
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}
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#[test]
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fn inline_code_styled() {
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let text = from_str("Use `code` inline.");
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let styled = text
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.lines
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.iter()
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.flat_map(|line| &line.spans)
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.find(|span| span.content.as_ref() == "code")
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.cloned()
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.unwrap();
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assert!(styled.style.contains(Modifier::BOLD));
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}
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}
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