1//! Setext headings
2//!
3//! Paragraph underlined with `===` or `---`.
4//!
5//! <https://spec.commonmark.org/0.30/#setext-headings>
6use crate::parser::block::{BlockRule, BlockState};
7use crate::parser::inline::InlineRoot;
8use crate::plugins::cmark::block::paragraph::ParagraphScanner;
9use crate::{MarkdownIt, Node, NodeValue, Renderer};
10
11#[derive(Debug)]
12pub struct SetextHeader {
13 pub level: u8,
14 pub marker: char,
15}
16
17impl NodeValue for SetextHeader {
18 fn render(&self, node: &Node, fmt: &mut dyn Renderer) {
19 static TAG : [&str; 2] = [ "h1", "h2" ];
20 debug_assert!(self.level >= 1 && self.level <= 2);
21
22 fmt.cr();
23 fmt.open(TAG[self.level as usize - 1], &node.attrs);
24 fmt.contents(&node.children);
25 fmt.close(TAG[self.level as usize - 1]);
26 fmt.cr();
27 }
28}
29
30pub fn add(md: &mut MarkdownIt) {
31 md.block.add_rule::<LHeadingScanner>()
32 .before::<ParagraphScanner>()
33 .after_all();
34}
35
36#[doc(hidden)]
37pub struct LHeadingScanner;
38impl BlockRule for LHeadingScanner {
39 fn check(_: &mut BlockState) -> Option<()> {
40 None // can't interrupt any tags
41 }
42
43 fn run(state: &mut BlockState) -> Option<(Node, usize)> {
44
45 if state.line_indent(state.line) >= state.md.max_indent { return None; }
46
47 let start_line = state.line;
48 let mut next_line = start_line;
49 let mut level = 0;
50
51 'outer: loop {
52 next_line += 1;
53
54 if next_line >= state.line_max || state.is_empty(next_line) { break; }
55
56 // this may be a code block normally, but after paragraph
57 // it's considered a lazy continuation regardless of what's there
58 if state.line_indent(next_line) >= state.md.max_indent { continue; }
59
60 //
61 // Check for underline in setext header
62 //
63 if state.line_indent(next_line) >= 0 {
64 let mut chars = state.get_line(next_line).chars().peekable();
65 if let Some(marker @ ('-' | '=')) = chars.next() {
66 while Some(&marker) == chars.peek() { chars.next(); }
67 while let Some(' ' | '\t') = chars.peek() { chars.next(); }
68 if chars.next().is_none() {
69 level = if marker == '=' { 1 } else { 2 };
70 break 'outer;
71 }
72 }
73 }
74
75 // quirk for blockquotes, this line should already be checked by that rule
76 if state.line_offsets[next_line].indent_nonspace < 0 { continue; }
77
78 // Some tags can terminate paragraph without empty line.
79 let old_state_line = state.line;
80 state.line = next_line;
81 if state.test_rules_at_line() {
82 state.line = old_state_line;
83 break 'outer;
84 }
85 state.line = old_state_line;
86 }
87
88
89 if level == 0 {
90 // Didn't find valid underline
91 return None;
92 }
93
94 let (content, mapping) = state.get_lines(start_line, next_line, state.blk_indent, false);
95
96 let mut node = Node::new(SetextHeader {
97 level,
98 marker: if level == 2 { '-' } else { '=' }
99 });
100 node.children.push(Node::new(InlineRoot::new(content, mapping)));
101
102 Some((node, next_line + 1 - start_line))
103 }
104}