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 = yog_ids::registry_of(kind).replace(yog_ids::sep::PATH, ".");
41    let key = format!("tag.{registry}.{}", id.replace([':', '/'], "."));
42    translation(&key).map_or_else(|| id.to_string(), |text| format_translation(&text, &[]))
43}
44
45/// [`tr`] with arguments for the text's format specifiers — see
46/// [`format_translation`]. The [`tr!`](crate::tr!) macro is shorter.
47pub fn tr_args(key: &str, args: &[&dyn Display]) -> String {
48    format_translation(&translation(key).unwrap_or_else(|| key.to_string()), args)
49}
50
51/// Fills Minecraft-style format specifiers in `pattern` (what lang files
52/// use): `%s`/`%d` take the next argument, `%1$s`/`%2$d` a numbered one
53/// (from 1), `%%` is a literal `%`. A specifier without an argument stays
54/// as written.
55pub fn format_translation(pattern: &str, args: &[&dyn Display]) -> String {
56    let mut out = String::with_capacity(pattern.len());
57    let mut next = 0;
58    let mut rest = pattern;
59    while let Some(pos) = rest.find('%') {
60        out.push_str(&rest[..pos]);
61        let spec = &rest[pos + 1..];
62        if let Some(after) = spec.strip_prefix('%') {
63            out.push('%');
64            rest = after;
65            continue;
66        }
67        if let Some(after) = spec.strip_prefix(['s', 'd']) {
68            match args.get(next) {
69                Some(arg) => {
70                    let _ = write!(out, "{arg}");
71                }
72                None => out.push_str(&rest[pos..pos + 2]),
73            }
74            next += 1;
75            rest = after;
76            continue;
77        }
78        let digits = spec.bytes().take_while(u8::is_ascii_digit).count();
79        let numbered = (digits > 0)
80            .then(|| spec[digits..].strip_prefix('$'))
81            .flatten()
82            .and_then(|s| s.strip_prefix(['s', 'd']));
83        match (numbered, spec[..digits].parse::<usize>()) {
84            (Some(after), Ok(n)) if n >= 1 => {
85                match args.get(n - 1) {
86                    Some(arg) => {
87                        let _ = write!(out, "{arg}");
88                    }
89                    None => out.push_str(&rest[pos..rest.len() - after.len()]),
90                }
91                rest = after;
92            }
93            _ => {
94                out.push('%');
95                rest = spec;
96            }
97        }
98    }
99    out.push_str(rest);
100    out
101}
102
103/// `tr!("key")` = [`tr`]`("key")`; `tr!("key", a, b)` fills the text's
104/// `%s` specifiers with `a` and `b` (anything `Display`) — see
105/// [`format_translation`].
106#[macro_export]
107macro_rules! tr {
108    ($key:expr_2021 $(,)?) => {
109        $crate::tr($key)
110    };
111    ($key:expr_2021, $($arg:expr_2021),+ $(,)?) => {
112        $crate::tr_args($key, &[$(&$arg as &dyn ::std::fmt::Display),+])
113    };
114}
115
116#[cfg(test)]
117mod tests {
118    use super::*;
119
120    #[test]
121    fn formats_like_minecraft() {
122        assert_eq!(
123            format_translation("%s of %s mods", &[&3, &"58"]),
124            "3 of 58 mods"
125        );
126        assert_eq!(format_translation("%2$s, %1$s", &[&"a", &"b"]), "b, a");
127        assert_eq!(format_translation("100%% by %s", &[&"X"]), "100% by X");
128        assert_eq!(format_translation("%d items", &[&5]), "5 items");
129        assert_eq!(
130            format_translation("missing %s and %3$s", &[]),
131            "missing %s and %3$s"
132        );
133        assert_eq!(format_translation("50% off %x", &[&1]), "50% off %x");
134        assert_eq!(format_translation("trailing %", &[]), "trailing %");
135        assert_eq!(format_translation("Привет, %s!", &[&"мир"]), "Привет, мир!");
136    }
137
138    #[test]
139    fn unknown_key_without_runtime_is_the_key() {
140        assert_eq!(tr("mymod.nothing"), "mymod.nothing");
141        assert_eq!(crate::tr!("count %s", 4), "count 4");
142    }
143}
yog_api/lang.rs

yog_api/
lang.rs
