markdown_it/plugins/cmark/inline/
newline.rs

1//! Line breaks
2//!
3//! Processes EOL (`\n`, soft and hard breaks).
4//!
5//!  - <https://spec.commonmark.org/0.30/#hard-line-breaks>
6//!  - <https://spec.commonmark.org/0.30/#soft-line-breaks>
7use crate::parser::inline::{InlineRule, InlineState};
8use crate::{MarkdownIt, Node, NodeValue, Renderer};
9
10#[derive(Debug)]
11pub struct Hardbreak;
12
13impl NodeValue for Hardbreak {
14    fn render(&self, _: &Node, fmt: &mut dyn Renderer) {
15        fmt.self_close("br", &[]);
16        fmt.cr();
17    }
18}
19
20#[derive(Debug)]
21pub struct Softbreak;
22
23impl NodeValue for Softbreak {
24    fn render(&self, _: &Node, fmt: &mut dyn Renderer) {
25        fmt.cr();
26    }
27}
28
29pub fn add(md: &mut MarkdownIt) {
30    md.inline.add_rule::<NewlineScanner>();
31}
32
33#[doc(hidden)]
34pub struct NewlineScanner;
35impl InlineRule for NewlineScanner {
36    const MARKER: char = '\n';
37
38    fn check(state: &mut InlineState) -> Option<usize> {
39        // check rule is required because run() modifies trailing text
40        let mut chars = state.src[state.pos..state.pos_max].chars();
41        if chars.next().unwrap() != '\n' { return None; }
42        Some(1)
43    }
44
45    fn run(state: &mut InlineState) -> Option<(Node, usize)> {
46        let mut chars = state.src[state.pos..state.pos_max].chars();
47
48        if chars.next().unwrap() != '\n' { return None; }
49
50        let mut pos = state.pos;
51        pos += 1;
52
53        // skip leading whitespaces from next line
54        while let Some(' ' | '\t') = chars.next() {
55            pos += 1;
56        }
57
58        // '  \n' -> hardbreak
59        let mut tail_size = 0;
60        let trailing_text = state.trailing_text_get();
61
62        for ch in trailing_text.chars().rev() {
63            if ch == ' ' {
64                tail_size += 1;
65            } else {
66                break;
67            }
68        }
69
70        state.trailing_text_pop(tail_size);
71
72        let node = if tail_size >= 2 {
73            Node::new(Hardbreak)
74        } else {
75            Node::new(Softbreak)
76        };
77
78        state.pos -= tail_size; // backtrack to include tail in source maps
79        Some((node, pos - state.pos))
80    }
81}
markdown_it/plugins/cmark/inline/newline.rs

markdown_it/plugins/cmark/inline/
newline.rs
