Add furigana tera filter

Cargo.lock

@@ -2502,9 +2502,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.8.3"
+version = "1.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "81ca098a9821bd52d6b24fd8b10bd081f47d39c22778cafaa75a2857a62c6390"
+checksum = "d0ab3ca65655bb1e41f2a8c8cd662eb4fb035e67c3f78da1d61dffe89d07300f"
 dependencies = [
  "aho-corasick 1.0.1",
  "memchr",
@@ -3279,6 +3279,7 @@ dependencies = [
  "poise",
  "r2d2",
  "r2d2_sqlite",
+ "regex",
  "reqwest",
  "rocket 0.5.0-rc.3",
  "rocket_contrib",

Cargo.toml

@@ -16,6 +16,7 @@ gettext = "0.4.0"
 poise = "0.5.5"
 r2d2 = "0.8.10"
 r2d2_sqlite = "0.22.0"
+regex = "1.8.4"
 reqwest = "0.11.18"
 rocket = { version = "=0.5.0-rc.3", features = ["secrets", "json"] }
 rocket_contrib = { version = "0.4.11", features = ["templates"] }

src/main.rs

@@ -21,7 +21,7 @@ use routes::*;
 mod i18n;
 use i18n::{i18n_filter, load_catalogs};
 
-use crate::i18n::langs_filter;
+use crate::{i18n::langs_filter, utils::furigana_filter};
 
 mod prelude;
 
@@ -106,6 +106,12 @@ async fn rocket() -> Result<Rocket<Ignite>, rocket::Error> {
                 move |value: &Value, args: &HashMap<String, Value>| {
                     langs_filter(value, args, &langs)
                 },
+            );
+            engines.tera.register_filter(
+                "furigana",
+                move |value: &Value, args: &HashMap<String, Value>| {
+                    furigana_filter(value, args)
+                },
             )
         }))
         .attach(SassFairing::default())

src/models/challenge.rs

@@ -4,7 +4,7 @@ use std::str::FromStr;
 use serde::{Deserialize, Deserializer, Serialize};
 use serde_yaml::Value;
 
-use crate::prelude::*;
+use crate::{prelude::*};
 
 #[derive(Serialize, Deserialize)]
 pub struct Challenge {

src/utils/furigana.rs

@@ -0,0 +1,36 @@
+use std::collections::HashMap;
+
+use regex::Regex;
+use rocket_dyn_templates::tera::{self, Value};
+
+pub fn furigana_to_html(text: &str) -> String {
+    // Original regular expression: \[([^\]]*)\]{([^\}]*)}
+    // https://regexr.com/6dspa
+    // https://blog.elnu.com/2022/01/furigana-in-markdown-using-regular-expressions/
+    // The regex crate users curly braces {} as repetition qualifiers,
+    // so { needs to be escaped as \{
+    // Curly brace literals \{ need to have their backslash escaped as \\{
+    // TODO: Modify so <span lang="ja"> only wraps continuous sections of furigana
+    let re = Regex::new(r"\[([^\]]*)\]\{([^\\}]*)}").unwrap();
+    format!("<span lang=\"ja\">{}</span>", re.replace_all(text, "<ruby>$1<rp>(</rp><rt>$2</rt><rp>)</rp></ruby>"))
+}
+
+pub fn furigana_filter(value: &Value, _args: &HashMap<String, Value>) -> tera::Result<Value> {
+    Ok(Value::String(furigana_to_html(value.as_str().expect("The furigana input must be a string"))))
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn furigana_to_html() {
+        use super::furigana_to_html;
+        assert_eq!(
+            furigana_to_html("[振]{ふ}り[仮]{が}[名]{な}"),
+            "<span lang=\"ja\">\
+                <ruby>振<rp>(</rp><rt>ふ</rt><rp>)</rp></ruby>り\
+                <ruby>仮<rp>(</rp><rt>が</rt><rp>)</rp></ruby>\
+                <ruby>名<rp>(</rp><rt>な</rt><rp>)</rp></ruby>\
+                </span>"
+        );
+    }
+}

src/utils/mod.rs

@@ -6,3 +6,6 @@ pub use headers::*;
 
 mod challenge;
 pub use challenge::*;
+
+mod furigana;
+pub use furigana::*;