yog_api/
lang.rs

1//! Translations — text in the player's language, from the lang files the
2//! game loaded (a mod's `.yres` texts become them at `yog build`).
3//!
4//! ```ignore
5//! let title = yog_api::tr("mymod.screen.title");
6//! let count = yog_api::tr!("mymod.screen.count", shown, total); // "%s of %s mods"
7//! ```
8
9use std::fmt::{Display, Write as _};
10
11use yog_abi::YogStr;
12
13/// The text of translation `key` in the current language, unformatted —
14/// `None` when no lang file defines it (or before the mod registered).
15pub fn translation(key: &str) -> Option<String> {
16    let api = crate::registry::global_api();
17    if api.is_null() {
18        return None;
19    }
20    let owned = unsafe { ((*api).translate)((*api).ctx, YogStr::from_str(key)) };
21    crate::registry::take_owned(unsafe { (*api).free_str }, owned)
22}
23
24/// The text of translation `key` in the current language, or `key` itself
25/// when it has none — what Minecraft shows for an unknown key, so a missing
26/// translation is easy to spot. Call it each time the text is shown (e.g.
27/// while building a UI tree): the player can switch language at any time.
28pub fn tr(key: &str) -> String {
29    match translation(key) {
30        Some(text) => format_translation(&text, &[]),
31        None => key.to_string(),
32    }
33}
34
35/// A tag's name in the player's language — `kind` the content's
36/// (`item`, `block`, `entity`, `fluid`, `biome`), `id` the tag's
37/// (`yog:ingots/iron`): the translation recipe viewers show
38/// (`tag.item.yog.ingots.iron`), else the id itself.
39pub fn tag_name(kind: &str, id: &str) -> String {
40    let registry = match kind {
41        "entity" => "entity_type",
42        "biome" => "worldgen.biome",
43        other => other,
44    };
45    let key = format!("tag.{registry}.{}", id.replace([':', '/'], "."));
46    translation(&key).map_or_else(|| id.to_string(), |text| format_translation(&text, &[]))
47}
48
49/// [`tr`] with arguments for the text's format specifiers — see
50/// [`format_translation`]. The [`tr!`](crate::tr!) macro is shorter.
51pub fn tr_args(key: &str, args: &[&dyn Display]) -> String {
52    format_translation(&translation(key).unwrap_or_else(|| key.to_string()), args)
53}
54
55/// Fills Minecraft-style format specifiers in `pattern` (what lang files
56/// use): `%s`/`%d` take the next argument, `%1$s`/`%2$d` a numbered one
57/// (from 1), `%%` is a literal `%`. A specifier without an argument stays
58/// as written.
59pub fn format_translation(pattern: &str, args: &[&dyn Display]) -> String {
60    let mut out = String::with_capacity(pattern.len());
61    let mut next = 0;
62    let mut rest = pattern;
63    while let Some(pos) = rest.find('%') {
64        out.push_str(&rest[..pos]);
65        let spec = &rest[pos + 1..];
66        if let Some(after) = spec.strip_prefix('%') {
67            out.push('%');
68            rest = after;
69            continue;
70        }
71        if let Some(after) = spec.strip_prefix(['s', 'd']) {
72            match args.get(next) {
73                Some(arg) => {
74                    let _ = write!(out, "{arg}");
75                }
76                None => out.push_str(&rest[pos..pos + 2]),
77            }
78            next += 1;
79            rest = after;
80            continue;
81        }
82        let digits = spec.bytes().take_while(u8::is_ascii_digit).count();
83        let numbered = (digits > 0)
84            .then(|| spec[digits..].strip_prefix('$'))
85            .flatten()
86            .and_then(|s| s.strip_prefix(['s', 'd']));
87        match (numbered, spec[..digits].parse::<usize>()) {
88            (Some(after), Ok(n)) if n >= 1 => {
89                match args.get(n - 1) {
90                    Some(arg) => {
91                        let _ = write!(out, "{arg}");
92                    }
93                    None => out.push_str(&rest[pos..rest.len() - after.len()]),
94                }
95                rest = after;
96            }
97            _ => {
98                out.push('%');
99                rest = spec;
100            }
101        }
102    }
103    out.push_str(rest);
104    out
105}
106
107/// `tr!("key")` = [`tr`]`("key")`; `tr!("key", a, b)` fills the text's
108/// `%s` specifiers with `a` and `b` (anything `Display`) — see
109/// [`format_translation`].
110#[macro_export]
111macro_rules! tr {
112    ($key:expr_2021 $(,)?) => {
113        $crate::tr($key)
114    };
115    ($key:expr_2021, $($arg:expr_2021),+ $(,)?) => {
116        $crate::tr_args($key, &[$(&$arg as &dyn ::std::fmt::Display),+])
117    };
118}
119
120#[cfg(test)]
121mod tests {
122    use super::*;
123
124    #[test]
125    fn formats_like_minecraft() {
126        assert_eq!(
127            format_translation("%s of %s mods", &[&3, &"58"]),
128            "3 of 58 mods"
129        );
130        assert_eq!(format_translation("%2$s, %1$s", &[&"a", &"b"]), "b, a");
131        assert_eq!(format_translation("100%% by %s", &[&"X"]), "100% by X");
132        assert_eq!(format_translation("%d items", &[&5]), "5 items");
133        assert_eq!(
134            format_translation("missing %s and %3$s", &[]),
135            "missing %s and %3$s"
136        );
137        assert_eq!(format_translation("50% off %x", &[&1]), "50% off %x");
138        assert_eq!(format_translation("trailing %", &[]), "trailing %");
139        assert_eq!(format_translation("Привет, %s!", &[&"мир"]), "Привет, мир!");
140    }
141
142    #[test]
143    fn unknown_key_without_runtime_is_the_key() {
144        assert_eq!(tr("mymod.nothing"), "mymod.nothing");
145        assert_eq!(crate::tr!("count %s", 4), "count 4");
146    }
147}
yog_api/lang.rs

yog_api/
lang.rs
