Restructure markdown highlighter

src/markdown/ast.rs

@@ -0,0 +1,54 @@
+use super::span::Span;
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum Heading {
+    H1,
+    H2,
+    H3,
+    H4,
+    H5,
+    H6,
+}
+
+#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
+pub struct Style {
+    /// # heading (large text)
+    pub heading: Option<Heading>,
+
+    /// > quoted (slightly dimmer color or other font style)
+    pub quoted: bool,
+
+    /// `code` (monospace, some other color)
+    pub code: bool,
+
+    /// self.strong* (emphasized, e.g. bold)
+    pub strong: bool,
+
+    /// _underline_
+    pub underline: bool,
+
+    /// ~strikethrough~
+    pub strikethrough: bool,
+
+    /// /italics/
+    pub italics: bool,
+
+    /// $small$
+    pub small: bool,
+
+    /// ^raised^
+    pub raised: bool,
+}
+
+pub enum MarkdownItem<'a> {
+    Text {
+        span: Span<'a>,
+        style: Style,
+    },
+
+    CodeBlock {
+        all: Span<'a>,
+        language: Span<'a>,
+        code: Span<'a>,
+    },
+}