diff options
Diffstat (limited to 'shakehand/src/lib.rs')
| -rw-r--r-- | shakehand/src/lib.rs | 63 |
1 files changed, 59 insertions, 4 deletions
diff --git a/shakehand/src/lib.rs b/shakehand/src/lib.rs index 419e088..404690c 100644 --- a/shakehand/src/lib.rs +++ b/shakehand/src/lib.rs @@ -79,6 +79,30 @@ //! let greeting = Global::greeting(Global::world()); //! ``` //! +//! ## 5. Fallback Chain (Optional) +//! +//! You can configure a **fallback chain** in your `Cargo.toml` under `[package.metadata.shakehand]`. +//! When a language has no translation for a key, the system will automatically walk the chain +//! to find the nearest language that has one. +//! +//! ```toml +//! [package.metadata.shakehand] +//! # For any language not explicitly listed, fall back to English +//! fallback.other = "en" +//! # Specific fallback rules +//! fallback.zh_HK = "zh_CN" # Hong Kong Trad -> Simplified Chinese +//! fallback.zh_TW = "zh_CN" # Taiwan Trad -> Simplified Chinese +//! fallback.zh_CN = "en" # Simplified Chinese -> English +//! fallback.it = "fr" # Italian -> French +//! ``` +//! +//! The chain resolution is **at runtime via a generated `FallbackSolver`**: +//! - Each language has a `try_fallback_once()` step defined in a compile-time generated match. +//! - Translation functions loop through the chain until a language with the value is found. +//! - `fallback.other` is the ultimate fallback (falls back to `locale!`'s `fallback` parameter if unset). +//! - All languages in the chain are automatically added to the `Languages` enum, even if they +//! have no translations in the locale files. +//! //! # Contributing //! //! Directly open a PR to the [repository](https://github.com/catilgrass/shakehand) and mention [@Weicao-CatilGrass](https://github.com/Weicao-CatilGrass). @@ -131,15 +155,46 @@ pub fn locale(input: TokenStream) -> TokenStream { } } + // Read fallback chain from the crate's Cargo.toml [package.metadata.shakehand] + let fallback_config = analyzer::read_fallback_from_manifest(&manifest_dir); + + // `default_fallback`: use `fallback.other` from Cargo.toml, else the macro's `fallback` param + let default_fallback = fallback_config + .as_ref() + .map(|c| c.default_fallback.as_str()) + .unwrap_or(&input.fallback) + .to_string(); + let fallback_map = fallback_config.map(|c| c.fallback_map).unwrap_or_default(); + + // Add all languages referenced in the fallback chain (keys and values) to `all_languages`, + // so the `Languages` enum includes variants that the chain may reference. + for (k, v) in &fallback_map { + all_languages.insert(k.clone()); + all_languages.insert(v.clone()); + } + all_languages.insert(default_fallback.clone()); + if parsed_files.is_empty() { - let lang_enum = - shakehand::generate_module(parsed_files, all_languages, input.fallback, &input.path); + let lang_enum = shakehand::generate_module( + parsed_files, + all_languages, + input.fallback, + fallback_map, + default_fallback, + &input.path, + ); return TokenStream::from(quote::quote! { #lang_enum }); } - let generated = - shakehand::generate_module(parsed_files, all_languages, input.fallback, &input.path); + let generated = shakehand::generate_module( + parsed_files, + all_languages, + input.fallback, + fallback_map, + default_fallback, + &input.path, + ); TokenStream::from(generated) } |