vecslide_core/
typst_split.rs

1/// Preamble injected before every slide snippet.
2/// Background is transparent so the viewer can apply its own theme.
3const SLIDE_PREAMBLE: &str = "#set page(width: 1920pt, height: 1080pt, margin: 2em, fill: none)\n\
4                               #set text(font: \"Noto Sans\", weight: \"bold\", size: 24pt)\n\
5                               #show math.equation: set text(font: \"New Computer Modern Sans Math\", weight: \"regular\")\n\
6                               #set heading(numbering: none)\n";
7
8/// Metadata parsed from the optional YAML front-matter block at the top of a `.typ` file.
9#[derive(Debug, Default)]
10pub struct TypstFrontmatter {
11    pub title: Option<String>,
12    pub author: Option<String>,
13}
14
15/// Splits a `.typ` source file into individual slide snippets.
16///
17/// The file may start with a YAML front-matter block delimited by `---` lines.
18/// Slides are separated by `\n----\n` (four dashes on their own line).
19/// Each snippet has `SLIDE_PREAMBLE` prepended so it can be compiled independently.
20pub fn split_typst_slides(source: &str) -> (TypstFrontmatter, Vec<String>) {
21    let (frontmatter, body) = parse_frontmatter(source);
22
23    let slides: Vec<String> = body
24        .split("\n----\n")
25        .map(str::trim)
26        .filter(|s| !s.is_empty())
27        .map(|s| format!("{SLIDE_PREAMBLE}\n{s}"))
28        .collect();
29
30    (frontmatter, slides)
31}
32
33/// Parses the optional YAML front-matter and returns (frontmatter, remaining body).
34fn parse_frontmatter(source: &str) -> (TypstFrontmatter, &str) {
35    // Front-matter must start at the very beginning with "---\n"
36    if !source.starts_with("---\n") {
37        return (TypstFrontmatter::default(), source);
38    }
39
40    // Find the closing "---" line
41    let rest = &source[4..]; // skip opening "---\n"
42    if let Some(end_pos) = rest.find("\n---\n") {
43        let yaml_str = &rest[..end_pos];
44        let body = &rest[end_pos + 5..]; // skip "\n---\n"
45
46        let frontmatter = parse_yaml_frontmatter(yaml_str);
47        (frontmatter, body)
48    } else {
49        // Malformed front-matter: treat whole source as body
50        (TypstFrontmatter::default(), source)
51    }
52}
53
54fn parse_yaml_frontmatter(yaml: &str) -> TypstFrontmatter {
55    let mut fm = TypstFrontmatter::default();
56    for line in yaml.lines() {
57        if let Some(rest) = line.strip_prefix("title:") {
58            fm.title = Some(rest.trim().trim_matches('"').to_string());
59        } else if let Some(rest) = line.strip_prefix("author:") {
60            fm.author = Some(rest.trim().trim_matches('"').to_string());
61        }
62    }
63    fm
64}
65
66#[cfg(test)]
67mod tests {
68    use super::*;
69
70    #[test]
71    fn splits_on_dashes() {
72        let src = "slide one\n----\nslide two\n----\nslide three";
73        let (_, slides) = split_typst_slides(src);
74        assert_eq!(slides.len(), 3);
75        assert!(slides[0].contains("slide one"));
76        assert!(slides[1].contains("slide two"));
77        assert!(slides[2].contains("slide three"));
78    }
79
80    #[test]
81    fn each_slide_has_preamble() {
82        let src = "content";
83        let (_, slides) = split_typst_slides(src);
84        assert_eq!(slides.len(), 1);
85        assert!(slides[0].contains("#set page"));
86    }
87
88    #[test]
89    fn empty_sections_are_ignored() {
90        let src = "a\n----\n\n----\nb";
91        let (_, slides) = split_typst_slides(src);
92        assert_eq!(slides.len(), 2);
93    }
94
95    #[test]
96    fn frontmatter_is_parsed() {
97        let src = "---\ntitle: My Talk\nauthor: Prof. Rossi\n---\nslide one";
98        let (fm, slides) = split_typst_slides(src);
99        assert_eq!(fm.title.as_deref(), Some("My Talk"));
100        assert_eq!(fm.author.as_deref(), Some("Prof. Rossi"));
101        assert_eq!(slides.len(), 1);
102        assert!(slides[0].contains("slide one"));
103    }
104
105    #[test]
106    fn no_frontmatter_works() {
107        let src = "slide one\n----\nslide two";
108        let (fm, slides) = split_typst_slides(src);
109        assert!(fm.title.is_none());
110        assert_eq!(slides.len(), 2);
111    }
112}
vecslide_core/typst_split.rs

vecslide_core/
typst_split.rs
