rs-rich 0.0.7

A faithful Rust port of the Python `rich` terminal-rendering library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106

//! Emoji shortcode replacement.
//!
//! Port of upstream `rich/_emoji_replace.py` + the full `rich/_emoji_codes.py`
//! table (see `emoji_codes.rs`). [`replace`] turns `:name:` shortcodes into
//! emoji, with optional `:name-emoji:` / `:name-text:` variant selectors.
//! Unknown codes are left untouched (matching upstream).

const VARIANT_EMOJI: &str = "\u{fe0f}";
const VARIANT_TEXT: &str = "\u{fe0e}";

/// Replace `:name:` emoji shortcodes in `text`. Port of `_emoji_replace`.
///
/// Mirrors one `re.sub` over `(:(\S*?)(?:(?:\-)(emoji|text))?:)`: every match,
/// including an unknown code or an empty `::`, is consumed, and scanning
/// resumes after its closing colon.
pub fn replace(text: &str) -> String {
    let chars: Vec<char> = text.chars().collect();
    let len = chars.len();
    let mut out = String::with_capacity(text.len());
    let mut index = 0;

    while index < len {
        if chars[index] == ':' {
            // The lazy `\S*?` stops at the first ':' that follows only
            // non-whitespace characters.
            let mut end = index + 1;
            while end < len && !is_python_space(chars[end]) && chars[end] != ':' {
                end += 1;
            }
            if end < len && chars[end] == ':' {
                let body: String = chars[index + 1..end].iter().collect();
                match lookup(&body) {
                    Some(replacement) => out.push_str(&replacement),
                    None => out.extend(&chars[index..=end]),
                }
                index = end + 1;
                continue;
            }
        }
        out.push(chars[index]);
        index += 1;
    }
    out
}

/// Python's `str.isspace()`, which `\s` follows for `str` patterns. Unlike
/// `char::is_whitespace` it includes the separators U+001C..=U+001F.
fn is_python_space(c: char) -> bool {
    c.is_whitespace() || ('\u{1c}'..='\u{1f}').contains(&c)
}

/// Resolve a shortcode body (with optional variant suffix) to its replacement.
fn lookup(body: &str) -> Option<String> {
    let lower = body.to_lowercase();
    let (name, variant) = if let Some(name) = lower.strip_suffix("-emoji") {
        (name, VARIANT_EMOJI)
    } else if let Some(name) = lower.strip_suffix("-text") {
        (name, VARIANT_TEXT)
    } else {
        (lower.as_str(), "")
    };
    emoji_code(name).map(|code| format!("{code}{variant}"))
}

/// Resolve an emoji name to its glyph(s) from the full vendored table.
fn emoji_code(name: &str) -> Option<&'static str> {
    crate::emoji_codes::emoji_code(name)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn replaces_known_codes() {
        // Captured from real rich 15.0.0 `_emoji_replace`.
        assert_eq!(replace(":rocket:"), "\u{1f680}");
        assert_eq!(replace("hello :thumbs_up: world"), "hello \u{1f44d} world");
        assert_eq!(replace(":rocket: to :moon:"), "\u{1f680} to \u{1f314}");
    }

    #[test]
    fn leaves_unknown_and_bare_colons() {
        assert_eq!(replace(":not_a_real_emoji:"), ":not_a_real_emoji:");
        assert_eq!(replace("no emoji"), "no emoji");
        assert_eq!(replace("ratio 3:4 done"), "ratio 3:4 done");
    }

    #[test]
    fn variant_selectors() {
        assert_eq!(replace(":rocket-emoji:"), "\u{1f680}\u{fe0f}");
        assert_eq!(replace(":rocket-text:"), "\u{1f680}\u{fe0e}");
    }

    #[test]
    fn scanning_resumes_after_every_match() {
        // Captured from real rich 15.0.0 `_emoji_replace` (#448).
        assert_eq!(replace(" -:界[ba:b: x"), " -:界[ba:b: x");
        assert_eq!(replace("::rocket:"), "::rocket:");
        assert_eq!(replace(":x:rocket:"), "\u{274c}rocket:");
        assert_eq!(replace(":rocket:rocket:"), "\u{1f680}rocket:");
        assert_eq!(replace(":ROCKET:"), "\u{1f680}");
        assert_eq!(replace("a:\u{1c}rocket:"), "a:\u{1c}rocket:");
        assert_eq!(replace(":\u{212a}rocket:"), ":\u{212a}rocket:");
    }
}