helix-term/src/ui/markdown.rs · helix

43 // // also 2021-03-04T16:33:58.553 helix_lsp::transport [INFO] <- {"contents":{"kind":"markdown","value":"\n```rust\ncore::num\n```\n\n```rust\npub const fn saturating_sub(self, rhs:Self) ->Self\n```\n\n---\n\n```rust\n```"},"range":{"end":{"character":61,"line":101},"start":{"character":47,"line":101}}}

44 // let text = "\n```rust\ncore::iter::traits::iterator::Iterator\n```\n\n```rust\nfn collect<B: FromIterator<Self::Item>>(self) -> B\nwhere\n Self: Sized,\n```\n\n---\n\nTransforms an iterator into a collection.\n\n`collect()` can take anything iterable, and turn it into a relevant\ncollection. This is one of the more powerful methods in the standard\nlibrary, used in a variety of contexts.\n\nThe most basic pattern in which `collect()` is used is to turn one\ncollection into another. You take a collection, call [`iter`](https://doc.rust-lang.org/nightly/core/iter/traits/iterator/trait.Iterator.html) on it,\ndo a bunch of transformations, and then `collect()` at the end.\n\n`collect()` can also create instances of types that are not typical\ncollections. For example, a [`String`](https://doc.rust-lang.org/nightly/core/iter/std/string/struct.String.html) can be built from [`char`](type@char)s,\nand an iterator of [`Result<T, E>`](https://doc.rust-lang.org/nightly/core/result/enum.Result.html) items can be collected\ninto `Result<Collection<T>, E>`. See the examples below for more.\n\nBecause `collect()` is so general, it can cause problems with type\ninference. As such, `collect()` is one of the few times you'll see\nthe syntax affectionately known as the 'turbofish': `::<>`. This\nhelps the inference algorithm understand specifically which collection\nyou're trying to collect into.\n\n# Examples\n\nBasic usage:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled: Vec<i32> = a.iter()\n .map(|&x| x * 2)\n .collect();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nNote that we needed the `: Vec<i32>` on the left-hand side. This is because\nwe could collect into, for example, a [`VecDeque<T>`](https://doc.rust-lang.org/nightly/core/iter/std/collections/struct.VecDeque.html) instead:\n\n```rust\nuse std::collections::VecDeque;\n\nlet a = [1, 2, 3];\n\nlet doubled: VecDeque<i32> = a.iter().map(|&x| x * 2).collect();\n\nassert_eq!(2, doubled[0]);\nassert_eq!(4, doubled[1]);\nassert_eq!(6, doubled[2]);\n```\n\nUsing the 'turbofish' instead of annotating `doubled`:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled = a.iter().map(|x| x * 2).collect::<Vec<i32>>();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nBecause `collect()` only cares about what you're collecting into, you can\nstill use a partial type hint, `_`, with the turbofish:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled = a.iter().map(|x| x * 2).collect::<Vec<_>>();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nUsing `collect()` to make a [`String`](https://doc.rust-lang.org/nightly/core/iter/std/string/struct.String.html):\n\n```rust\nlet chars = ['g', 'd', 'k', 'k', 'n'];\n\nlet hello: String = chars.iter()\n .map(|&x| x as u8)\n .map(|x| (x + 1) as char)\n .collect();\n\nassert_eq!(\"hello\", hello);\n```\n\nIf you have a list of [`Result<T, E>`](https://doc.rust-lang.org/nightly/core/result/enum.Result.html)s, you can use `collect()` to\nsee if any of them failed:\n\n```rust\nlet results = [Ok(1), Err(\"nope\"), Ok(3), Err(\"bad\")];\n\nlet result: Result<Vec<_>, &str> = results.iter().cloned().collect();\n\n// gives us the first error\nassert_eq!(Err(\"nope\"), result);\n\nlet results = [Ok(1), Ok(3)];\n\nlet result: Result<Vec<_>, &str> = results.iter().cloned().collect();\n\n// gives us the list of answers\nassert_eq!(Ok(vec![1, 3]), result);\n```";

45

46 let mut options = Options::empty();

47 options.insert(Options::ENABLE_STRIKETHROUGH);

48 let parser = Parser::new_ext(contents, options);

49

50 // TODO: if possible, render links as terminal hyperlinks: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda

51 let mut tags = Vec::new();

52 let mut spans = Vec::new();

53 let mut lines = Vec::new();

54

55 fn to_span(text: pulldown_cmark::CowStr) -> Span {

56 use std::ops::Deref;

57 Span::raw::<std::borrow::Cow<_>>(match text {

58 CowStr::Borrowed(s) => s.to_string().into(), // could retain borrow

59 CowStr::Boxed(s) => s.to_string().into(),

60 CowStr::Inlined(s) => s.deref().to_owned().into(),

61 })

62 }

63

64 let text_style = Style::default().fg(Color::Rgb(164, 160, 232)); // lavender

65 let code_style = Style::default().fg(Color::Rgb(255, 255, 255)); // white

66 let heading_style = Style::default().fg(Color::Rgb(219, 191, 239)); // lilac

67

68 for event in parser {

69 match event {

70 Event::Start(tag) => tags.push(tag),

71 Event::End(tag) => {

72 tags.pop();

73 match tag {

74 Tag::Heading(_) | Tag::Paragraph | Tag::CodeBlock(CodeBlockKind::Fenced(_)) => {

75 // whenever code block or paragraph closes, new line

76 let spans = std::mem::take(&mut spans);

77 if !spans.is_empty() {

78 lines.push(Spans::from(spans));

79 }

80 lines.push(Spans::default());

81 }

82 _ => (),

83 }

84 }

85 Event::Text(text) => {

86 // TODO: temp workaround

87 if let Some(Tag::CodeBlock(CodeBlockKind::Fenced(language))) = tags.last() {

88 if let Some(theme) = theme {

89 let rope = Rope::from(text.as_ref());

90 let syntax = loader

91 .language_config_for_scope(&format!("source.{}", language))

92 .and_then(|config| config.highlight_config(theme.scopes()))

93 .map(|config| Syntax::new(&rope, config));

94

95 if let Some(syntax) = syntax {

96 // if we have a syntax available, highlight_iter and generate spans

97 let mut highlights = Vec::new();

98

99 for event in syntax.highlight_iter(rope.slice(..), None, None, |_| None)

100 {

101 match event.unwrap() {

102 HighlightEvent::HighlightStart(span) => {

103 highlights.push(span);

104 }

105 HighlightEvent::HighlightEnd => {

106 highlights.pop();

107 }

108 HighlightEvent::Source { start, end } => {

109 let style = match highlights.first() {

110 Some(span) => theme.get(&theme.scopes()[span.0]),

111 None => text_style,

112 };

113

114 // TODO: replace tabs with indentation

115

116 let mut slice = &text[start..end];

117 // TODO: do we need to handle all unicode line endings

118 // here, or is just '\n' okay?

119 while let Some(end) = slice.find('\n') {

120 // emit span up to newline

121 let text = &slice[..end];

122 let text = text.replace('\t', " "); // replace tabs

123 let span = Span::styled(text, style);

124 spans.push(span);

125

126 // truncate slice to after newline

127 slice = &slice[end + 1..];

128

129 // make a new line

130 let spans = std::mem::take(&mut spans);

131 lines.push(Spans::from(spans));

132 }

133

134 // if there's anything left, emit it too

135 if !slice.is_empty() {

136 let span =

137 Span::styled(slice.replace('\t', " "), style);

138 spans.push(span);

139 }

140 }

141 }

142 }

143 } else {

144 for line in text.lines() {

145 let span = Span::styled(line.to_string(), code_style);

146 lines.push(Spans::from(span));

147 }

148 }

149 } else {

150 for line in text.lines() {

151 let span = Span::styled(line.to_string(), code_style);

152 lines.push(Spans::from(span));

153 }

154 }

155 } else if let Some(Tag::Heading(_)) = tags.last() {

156 let mut span = to_span(text);

157 span.style = heading_style;

158 spans.push(span);

159 } else {

160 let mut span = to_span(text);

161 span.style = text_style;

162 spans.push(span);

163 }

164 }

165 Event::Code(text) | Event::Html(text) => {

166 let mut span = to_span(text);

167 span.style = code_style;

168 spans.push(span);

169 }

170 Event::SoftBreak | Event::HardBreak => {

171 // let spans = std::mem::replace(&mut spans, Vec::new());

172 // lines.push(Spans::from(spans));

173 spans.push(Span::raw(" "));

174 }

175 Event::Rule => {

176 lines.push(Spans::from("---"));

177 lines.push(Spans::default());

178 }

179 // TaskListMarker(bool) true if checked

180 _ => {

181 log::warn!("unhandled markdown event {:?}", event);

182 }

183 }

184 // build up a vec of Paragraph tui widgets

185 }

186

187 if !spans.is_empty() {

188 lines.push(Spans::from(spans));

189 }

190

191 // if last line is empty, remove it

192 if let Some(line) = lines.last() {

193 if line.0.is_empty() {

194 lines.pop();

195 }

196 }

197

198 Text::from(lines)

199}

200impl Component for Markdown {

201 fn render(&mut self, area: Rect, surface: &mut Surface, cx: &mut Context) {

202 use tui::widgets::{Paragraph, Widget, Wrap};

203

204 let text = parse(&self.contents, Some(&cx.editor.theme), &self.config_loader);

205

206 let par = Paragraph::new(text)

207 .wrap(Wrap { trim: false })

208 .scroll((cx.scroll.unwrap_or_default() as u16, 0));

209

210 let area = Rect::new(area.x + 1, area.y + 1, area.width - 2, area.height - 2);

211 par.render(area, surface);

212 }

213

214 fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {

215 let contents = parse(&self.contents, None, &self.config_loader);

216 let padding = 2;

217 let width = std::cmp::min(contents.width() as u16 + padding, viewport.0);

218 let height = std::cmp::min(contents.height() as u16 + padding, viewport.1);

219 Some((width, height))

220 }

221}