Add serde implementation

unic-langid-impl/src/lib.rs

@@ -1,3 +1,5 @@
+#[cfg(feature = "serde")]
+mod serde;
 mod errors;
 mod layout_table;
 #[cfg(feature = "likelysubtags")]

unic-langid-impl/src/serde.rs

@@ -0,0 +1,61 @@
+use crate::LanguageIdentifier;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+impl Serialize for LanguageIdentifier {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+
+impl<'de> Deserialize<'de> for LanguageIdentifier {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct LanguageIdentifierVisitor;
+
+        impl<'de> serde::de::Visitor<'de> for LanguageIdentifierVisitor {
+            type Value = LanguageIdentifier;
+
+            fn expecting(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                write!(formatter, "A valid Unicode Language Identifier")
+            }
+
+            fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
+            where
+                E: serde::de::Error,
+            {
+                s.parse::<LanguageIdentifier>()
+                    .map_err(serde::de::Error::custom)
+            }
+        }
+
+        deserializer.deserialize_string(LanguageIdentifierVisitor)
+    }
+}
+
+#[test]
+fn serialize() -> Result<(), Box<dyn std::error::Error>> {
+    let fr = serde_json::json!("fr".parse::<LanguageIdentifier>()?);
+    let en = serde_json::json!("en-US".parse::<LanguageIdentifier>()?);
+
+    assert_eq!(serde_json::to_string(&fr)?, r#""fr""#);
+    assert_eq!(serde_json::to_string(&en)?, r#""en-US""#);
+
+    Ok(())
+}
+
+#[test]
+fn deserialize() -> Result<(), Box<dyn std::error::Error>> {
+    let fr = serde_json::from_str::<LanguageIdentifier>(r#""fr""#)?;
+    let en = serde_json::from_str::<LanguageIdentifier>(r#""en-US""#)?;
+
+    assert_eq!(fr, "fr".parse::<LanguageIdentifier>()?);
+    assert_eq!(en, "en-US".parse::<LanguageIdentifier>()?);
+
+    Ok(())
+}
+

unic-langid/Cargo.toml

@@ -24,6 +24,7 @@ unic-langid-macros = { version = "0.8", path = "../unic-langid-macros" }
 
 [features]
 default = []
+serde = ["unic-langid-impl/serde"]
 
 # Provide macros.
 macros = ["unic-langid-macros"]