Fix to prefer flow over definitions, setext headings

An undocumented part of CommonMark is how to deal with things in definition
labels or definition titles (which both can span multiple lines).
Can flow (or containers?) interrupt them?
They can according to the `cmark` reference parser, so this was implemented here.

This adds a new `Content` content type, which houses zero or more definitions,
and then zero-or-one paragraphs.
Content can be followed by a setext heading underline, which either turns
into a setext heading when the content ends in a paragraph, or turns into
the start of the following paragraph when it is followed by content that
starts with a paragraph, or turns into a stray paragraph.

1 files changed, 46 insertions, 5 deletions

diff --git a/src/event.rs b/src/event.rs
index de3f95f..a2626ee 100644
--- a/src/event.rs
+++ b/src/event.rs
@@ -554,6 +554,26 @@ pub enum Name {
     ///       ^ ^
     /// ```
     CodeTextSequence,
+    /// Content.
+    ///
+    /// ## Info
+    ///
+    /// *   **Context**:
+    ///     [flow content][crate::construct::flow]
+    /// *   **Content model**:
+    ///     [content][crate::construct::content]
+    /// *   **Construct**:
+    ///     [`content`][crate::construct::content]
+    ///
+    /// ## Example
+    ///
+    /// ```markdown
+    /// > | [a]: b
+    ///     ^^^^^^
+    /// > | c.
+    ///     ^^
+    /// ```
+    Content,
     /// Data.
     ///
     /// ## Info
@@ -1754,7 +1774,8 @@ pub enum Name {
     /// *   **Context**:
     ///     [`HeadingSetext`][Name::HeadingSetext]
     /// *   **Content model**:
-    ///     void
+    ///     [`HeadingSetextUnderlineSequence`][Name::HeadingSetextUnderlineSequence],
+    ///     [`SpaceOrTab`][Name::SpaceOrTab]
     /// *   **Construct**:
     ///     [`heading_setext`][crate::construct::heading_setext]
     ///
@@ -1766,6 +1787,25 @@ pub enum Name {
     ///     ^^^^^
     /// ```
     HeadingSetextUnderline,
+    /// Heading (setext) underline sequence.
+    ///
+    /// ## Info
+    ///
+    /// *   **Context**:
+    ///     [`HeadingSetext`][Name::HeadingSetext]
+    /// *   **Content model**:
+    ///     void
+    /// *   **Construct**:
+    ///     [`heading_setext`][crate::construct::heading_setext]
+    ///
+    /// ## Example
+    ///
+    /// ```markdown
+    ///   | alpha
+    /// > | =====
+    ///     ^^^^^
+    /// ```
+    HeadingSetextUnderlineSequence,
     /// Whole html (flow).
     ///
     /// ## Info
@@ -2914,13 +2954,12 @@ pub enum Name {
     ///          ^
     /// ```
     MdxJsxTagSelfClosingMarker,
-
-    /// Whole paragraph.
+    /// Paragraph.
     ///
     /// ## Info
     ///
     /// *   **Context**:
-    ///     [flow content][crate::construct::flow]
+    ///     [content][crate::construct::content]
     /// *   **Content model**:
     ///     [text content][crate::construct::text]
     /// *   **Construct**:
@@ -3340,7 +3379,7 @@ pub const VOID_EVENTS: [Name; 75] = [
     Name::HardBreakEscape,
     Name::HardBreakTrailing,
     Name::HeadingAtxSequence,
-    Name::HeadingSetextUnderline,
+    Name::HeadingSetextUnderlineSequence,
     Name::HtmlFlowData,
     Name::HtmlTextData,
     Name::LabelImageMarker,
@@ -3380,6 +3419,8 @@ pub const VOID_EVENTS: [Name; 75] = [
 pub enum Content {
     /// Represents [flow content][crate::construct::flow].
     Flow,
+    /// Represents [content][crate::construct::content].
+    Content,
     /// Represents [string content][crate::construct::string].
     String,
     /// Represents [text content][crate::construct::text].