rust-soundchange:在 Rust 中实现声音变化算法的工具

# Rust-soundchange A tool for implementing sound change algorithms. This is strictly modeled after Mark Rosenfelder's [Sound Change Applier][sca], with a necessary tweak for Rust's macro system. [sca]: http://zompist.com/scahelp.html Typical usage and the comparison with the original SCA rules: ``` #[macro_use] extern crate soundchange; #[macro_use] extern crate log; use soundchange::{CharOf, StrTo}; fn main() { // custom conditions let is_boundary = |c: Option<char>| c.is_none(); let is_vowel = |c: Option<char>| c.map_or(false, |c| "aeiou".contains_char(c)); let boundary = CharOf(&is_boundary); let vowel = CharOf(&is_vowel); // custom transformers let make_reverse = |s: &str, out: &mut String| out.extend(s.chars().rev()); let reverse = StrTo(&make_reverse); let s = "fihs".to_string(); let s = subst_rules! { s => // V=aeiou "f" [boundary] => "gh"; // f/gh/_# "f" => "ph"; // f/ph/_ ["w"] vowel ["m" vowel "n"] => "o"; // V/o/w_mVn "sh" ["o"] => "ti"; // sh/ti/_o [vowel] "hs" => reverse; // sh/\\/V_ "" [boundary] => "ing"; // /ing/_# }; assert_eq!(s, "phishing"); } ``` Note: You can use `RUST_LOG=4` for tracking any change on the string and rules that trigger that change. Also, a large number of rules may trigger a recursion limit on rustc; you have to split them in that case. Any expression in the left side is considered a "condition" for searching, and can be either `char`, `&str` or a function from `Option<char>` to `bool`. The function argument is an `Option` since it can look at the string boundary. `[]` indicates a context, and is not considered when the string gets transformed. (The behavior of conditions can be also customized by implementing `IntoCond` trait and/or `Search` trait. `&str` and the function implements both.) Any expression in the right side is considered a "transformer", and can be either `char`, `&str` or a function from `char` to `char`. When multiple characters have been matched, a function will be invoked for each character. (The behavior of transformers can be also customized by implementing `Transform` trait.) The actual processing is driven through the `subst` function, which is for convenience wrapped into the `subst_rules!` macro. The syntax should be self-explanatory, except that it returns a `CowString`. ## Case Study: English Pronunciation `src/english` provides a reimplementation of Mark Rosenfelder's [pronunciation algorithm][spell] for English. [spell]: http://zompist.com/spell.html