Use markup scopes for the Markdown component (#1363)

3 files changed, 172 insertions, 153 deletions

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index fc0db6ed..7144ebb9 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -5455,7 +5455,8 @@ fn hover(cx: &mut Context) {
 
                 // skip if contents empty
 
-                let contents = ui::Markdown::new(contents, editor.syn_loader.clone());
+                let contents =
+                    ui::Markdown::new(contents, editor.syn_loader.clone()).style_group("hover");
                 let popup = Popup::new("hover", contents);
                 if let Some(doc_popup) = compositor.find_id("hover") {
                     *doc_popup = popup;
diff --git a/helix-term/src/ui/completion.rs b/helix-term/src/ui/completion.rs
index c9ed3b4a..35afe81e 100644
--- a/helix-term/src/ui/completion.rs
+++ b/helix-term/src/ui/completion.rs
@@ -304,6 +304,9 @@ impl Component for Completion {
             let cursor_pos = doc.selection(view.id).primary().cursor(text);
             let coords = helix_core::visual_coords_at_pos(text, cursor_pos, doc.tab_width());
             let cursor_pos = (coords.row - view.offset.row) as u16;
+
+            let markdown_ui =
+                |content, syn_loader| Markdown::new(content, syn_loader).style_group("completion");
             let mut markdown_doc = match &option.documentation {
                 Some(lsp::Documentation::String(contents))
                 | Some(lsp::Documentation::MarkupContent(lsp::MarkupContent {
@@ -311,7 +314,7 @@ impl Component for Completion {
                     value: contents,
                 })) => {
                     // TODO: convert to wrapped text
-                    Markdown::new(
+                    markdown_ui(
                         format!(
                             "```{}\n{}\n```\n{}",
                             language,
@@ -326,7 +329,7 @@ impl Component for Completion {
                     value: contents,
                 })) => {
                     // TODO: set language based on doc scope
-                    Markdown::new(
+                    markdown_ui(
                         format!(
                             "```{}\n{}\n```\n{}",
                             language,
@@ -340,7 +343,7 @@ impl Component for Completion {
                     // TODO: copied from above
 
                     // TODO: set language based on doc scope
-                    Markdown::new(
+                    markdown_ui(
                         format!(
                             "```{}\n{}\n```",
                             language,
diff --git a/helix-term/src/ui/markdown.rs b/helix-term/src/ui/markdown.rs
index 00da2c11..003266d3 100644
--- a/helix-term/src/ui/markdown.rs
+++ b/helix-term/src/ui/markdown.rs
@@ -21,6 +21,10 @@ pub struct Markdown {
     contents: String,
 
     config_loader: Arc<syntax::Loader>,
+
+    text_style: String,
+    block_style: String,
+    heading_style: String,
 }
 
 // TODO: pre-render and self reference via Pin
@@ -31,121 +35,139 @@ impl Markdown {
         Self {
             contents,
             config_loader,
+            text_style: "markup.normal".into(),
+            block_style: "markup.raw.inline".into(),
+            heading_style: "markup.heading".into(),
         }
     }
-}
 
-fn parse<'a>(
-    contents: &'a str,
-    theme: Option<&Theme>,
-    loader: Arc<syntax::Loader>,
-) -> tui::text::Text<'a> {
-    // // 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}}}
-    // 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```";
-
-    let mut options = Options::empty();
-    options.insert(Options::ENABLE_STRIKETHROUGH);
-    let parser = Parser::new_ext(contents, options);
-
-    // TODO: if possible, render links as terminal hyperlinks: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
-    let mut tags = Vec::new();
-    let mut spans = Vec::new();
-    let mut lines = Vec::new();
-
-    fn to_span(text: pulldown_cmark::CowStr) -> Span {
-        use std::ops::Deref;
-        Span::raw::<std::borrow::Cow<_>>(match text {
-            CowStr::Borrowed(s) => s.into(),
-            CowStr::Boxed(s) => s.to_string().into(),
-            CowStr::Inlined(s) => s.deref().to_owned().into(),
-        })
+    pub fn style_group(mut self, suffix: &str) -> Self {
+        self.text_style = format!("markup.normal.{}", suffix);
+        self.block_style = format!("markup.raw.inline.{}", suffix);
+        self.heading_style = format!("markup.heading.{}", suffix);
+        self
     }
 
-    let text_style = theme.map(|theme| theme.get("ui.text")).unwrap_or_default();
-
-    // TODO: use better scopes for these, `markup.raw.block`, `markup.heading`
-    let code_style = theme
-        .map(|theme| theme.get("ui.text.focus"))
-        .unwrap_or_default(); // white
-    let heading_style = theme
-        .map(|theme| theme.get("ui.linenr.selected"))
-        .unwrap_or_default(); // lilac
-
-    for event in parser {
-        match event {
-            Event::Start(tag) => tags.push(tag),
-            Event::End(tag) => {
-                tags.pop();
-                match tag {
-                    Tag::Heading(_, _, _)
-                    | Tag::Paragraph
-                    | Tag::CodeBlock(CodeBlockKind::Fenced(_)) => {
-                        // whenever code block or paragraph closes, new line
-                        let spans = std::mem::take(&mut spans);
-                        if !spans.is_empty() {
-                            lines.push(Spans::from(spans));
+    fn parse(&self, theme: Option<&Theme>) -> tui::text::Text<'_> {
+        // // 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}}}
+        // 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```";
+
+        let mut options = Options::empty();
+        options.insert(Options::ENABLE_STRIKETHROUGH);
+        let parser = Parser::new_ext(&self.contents, options);
+
+        // TODO: if possible, render links as terminal hyperlinks: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
+        let mut tags = Vec::new();
+        let mut spans = Vec::new();
+        let mut lines = Vec::new();
+
+        fn to_span(text: pulldown_cmark::CowStr) -> Span {
+            use std::ops::Deref;
+            Span::raw::<std::borrow::Cow<_>>(match text {
+                CowStr::Borrowed(s) => s.into(),
+                CowStr::Boxed(s) => s.to_string().into(),
+                CowStr::Inlined(s) => s.deref().to_owned().into(),
+            })
+        }
+
+        macro_rules! get_theme {
+            ($s1: expr) => {
+                theme
+                    .map(|theme| theme.try_get($s1.as_str()))
+                    .flatten()
+                    .unwrap_or_default()
+            };
+        }
+        let text_style = get_theme!(self.text_style);
+        let code_style = get_theme!(self.block_style);
+        let heading_style = get_theme!(self.heading_style);
+
+        for event in parser {
+            match event {
+                Event::Start(tag) => tags.push(tag),
+                Event::End(tag) => {
+                    tags.pop();
+                    match tag {
+                        Tag::Heading(_, _, _)
+                        | Tag::Paragraph
+                        | Tag::CodeBlock(CodeBlockKind::Fenced(_)) => {
+                            // whenever code block or paragraph closes, new line
+                            let spans = std::mem::take(&mut spans);
+                            if !spans.is_empty() {
+                                lines.push(Spans::from(spans));
+                            }
+                            lines.push(Spans::default());
                         }
-                        lines.push(Spans::default());
+                        _ => (),
                     }
-                    _ => (),
                 }
-            }
-            Event::Text(text) => {
-                // TODO: temp workaround
-                if let Some(Tag::CodeBlock(CodeBlockKind::Fenced(language))) = tags.last() {
-                    if let Some(theme) = theme {
-                        let rope = Rope::from(text.as_ref());
-                        let syntax = loader
-                            .language_configuration_for_injection_string(language)
-                            .and_then(|config| config.highlight_config(theme.scopes()))
-                            .map(|config| Syntax::new(&rope, config, loader.clone()));
-
-                        if let Some(syntax) = syntax {
-                            // if we have a syntax available, highlight_iter and generate spans
-                            let mut highlights = Vec::new();
-
-                            for event in syntax.highlight_iter(rope.slice(..), None, None) {
-                                match event.unwrap() {
-                                    HighlightEvent::HighlightStart(span) => {
-                                        highlights.push(span);
-                                    }
-                                    HighlightEvent::HighlightEnd => {
-                                        highlights.pop();
-                                    }
-                                    HighlightEvent::Source { start, end } => {
-                                        let style = match highlights.first() {
-                                            Some(span) => theme.get(&theme.scopes()[span.0]),
-                                            None => text_style,
-                                        };
-
-                                        // TODO: replace tabs with indentation
-
-                                        let mut slice = &text[start..end];
-                                        // TODO: do we need to handle all unicode line endings
-                                        // here, or is just '\n' okay?
-                                        while let Some(end) = slice.find('\n') {
-                                            // emit span up to newline
-                                            let text = &slice[..end];
-                                            let text = text.replace('\t', "    "); // replace tabs
-                                            let span = Span::styled(text, style);
-                                            spans.push(span);
-
-                                            // truncate slice to after newline
-                                            slice = &slice[end + 1..];
-
-                                            // make a new line
-                                            let spans = std::mem::take(&mut spans);
-                                            lines.push(Spans::from(spans));
+                Event::Text(text) => {
+                    // TODO: temp workaround
+                    if let Some(Tag::CodeBlock(CodeBlockKind::Fenced(language))) = tags.last() {
+                        if let Some(theme) = theme {
+                            let rope = Rope::from(text.as_ref());
+                            let syntax = self
+                                .config_loader
+                                .language_configuration_for_injection_string(language)
+                                .and_then(|config| config.highlight_config(theme.scopes()))
+                                .map(|config| {
+                                    Syntax::new(&rope, config, self.config_loader.clone())
+                                });
+
+                            if let Some(syntax) = syntax {
+                                // if we have a syntax available, highlight_iter and generate spans
+                                let mut highlights = Vec::new();
+
+                                for event in syntax.highlight_iter(rope.slice(..), None, None) {
+                                    match event.unwrap() {
+                                        HighlightEvent::HighlightStart(span) => {
+                                            highlights.push(span);
                                         }
+                                        HighlightEvent::HighlightEnd => {
+                                            highlights.pop();
+                                        }
+                                        HighlightEvent::Source { start, end } => {
+                                            let style = match highlights.first() {
+                                                Some(span) => theme.get(&theme.scopes()[span.0]),
+                                                None => text_style,
+                                            };
+
+                                            // TODO: replace tabs with indentation
+
+                                            let mut slice = &text[start..end];
+                                            // TODO: do we need to handle all unicode line endings
+                                            // here, or is just '\n' okay?
+                                            while let Some(end) = slice.find('\n') {
+                                                // emit span up to newline
+                                                let text = &slice[..end];
+                                                let text = text.replace('\t', "    "); // replace tabs
+                                                let span = Span::styled(text, style);
+                                                spans.push(span);
+
+                                                // truncate slice to after newline
+                                                slice = &slice[end + 1..];
+
+                                                // make a new line
+                                                let spans = std::mem::take(&mut spans);
+                                                lines.push(Spans::from(spans));
+                                            }
 
-                                        // if there's anything left, emit it too
-                                        if !slice.is_empty() {
-                                            let span =
-                                                Span::styled(slice.replace('\t', "    "), style);
-                                            spans.push(span);
+                                            // if there's anything left, emit it too
+                                            if !slice.is_empty() {
+                                                let span = Span::styled(
+                                                    slice.replace('\t', "    "),
+                                                    style,
+                                                );
+                                                spans.push(span);
+                                            }
                                         }
                                     }
                                 }
+                            } else {
+                                for line in text.lines() {
+                                    let span = Span::styled(line.to_string(), code_style);
+                                    lines.push(Spans::from(span));
+                                }
                             }
                         } else {
                             for line in text.lines() {
@@ -153,68 +175,60 @@ fn parse<'a>(
                                 lines.push(Spans::from(span));
                             }
                         }
+                    } else if let Some(Tag::Heading(_, _, _)) = tags.last() {
+                        let mut span = to_span(text);
+                        span.style = heading_style;
+                        spans.push(span);
                     } else {
-                        for line in text.lines() {
-                            let span = Span::styled(line.to_string(), code_style);
-                            lines.push(Spans::from(span));
-                        }
+                        let mut span = to_span(text);
+                        span.style = text_style;
+                        spans.push(span);
                     }
-                } else if let Some(Tag::Heading(_, _, _)) = tags.last() {
-                    let mut span = to_span(text);
-                    span.style = heading_style;
-                    spans.push(span);
-                } else {
+                }
+                Event::Code(text) | Event::Html(text) => {
                     let mut span = to_span(text);
-                    span.style = text_style;
+                    span.style = code_style;
                     spans.push(span);
                 }
+                Event::SoftBreak | Event::HardBreak => {
+                    // let spans = std::mem::replace(&mut spans, Vec::new());
+                    // lines.push(Spans::from(spans));
+                    spans.push(Span::raw(" "));
+                }
+                Event::Rule => {
+                    let mut span = Span::raw("---");
+                    span.style = code_style;
+                    lines.push(Spans::from(span));
+                    lines.push(Spans::default());
+                }
+                // TaskListMarker(bool) true if checked
+                _ => {
+                    log::warn!("unhandled markdown event {:?}", event);
+                }
             }
-            Event::Code(text) | Event::Html(text) => {
-                let mut span = to_span(text);
-                span.style = code_style;
-                spans.push(span);
-            }
-            Event::SoftBreak | Event::HardBreak => {
-                // let spans = std::mem::replace(&mut spans, Vec::new());
-                // lines.push(Spans::from(spans));
-                spans.push(Span::raw(" "));
-            }
-            Event::Rule => {
-                let mut span = Span::raw("---");
-                span.style = code_style;
-                lines.push(Spans::from(span));
-                lines.push(Spans::default());
-            }
-            // TaskListMarker(bool) true if checked
-            _ => {
-                log::warn!("unhandled markdown event {:?}", event);
-            }
+            // build up a vec of Paragraph tui widgets
         }
-        // build up a vec of Paragraph tui widgets
-    }
 
-    if !spans.is_empty() {
-        lines.push(Spans::from(spans));
-    }
+        if !spans.is_empty() {
+            lines.push(Spans::from(spans));
+        }
 
-    // if last line is empty, remove it
-    if let Some(line) = lines.last() {
-        if line.0.is_empty() {
-            lines.pop();
+        // if last line is empty, remove it
+        if let Some(line) = lines.last() {
+            if line.0.is_empty() {
+                lines.pop();
+            }
         }
-    }
 
-    Text::from(lines)
+        Text::from(lines)
+    }
 }
+
 impl Component for Markdown {
     fn render(&mut self, area: Rect, surface: &mut Surface, cx: &mut Context) {
         use tui::widgets::{Paragraph, Widget, Wrap};
 
-        let text = parse(
-            &self.contents,
-            Some(&cx.editor.theme),
-            self.config_loader.clone(),
-        );
+        let text = self.parse(Some(&cx.editor.theme));
 
         let par = Paragraph::new(text)
             .wrap(Wrap { trim: false })
@@ -232,7 +246,8 @@ impl Component for Markdown {
         if padding >= viewport.1 || padding >= viewport.0 {
             return None;
         }
-        let contents = parse(&self.contents, None, self.config_loader.clone());
+        let contents = self.parse(None);
+
         // TODO: account for tab width
         let max_text_width = (viewport.0 - padding).min(120);
         let mut text_width = 0;