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2026-07-01 17:42:23 -04:00
parent 617c4465fb
commit 6b8f4ccb3d
9 changed files with 250 additions and 234 deletions
@@ -0,0 +1,46 @@
+use std::sync::LazyLock;
+use oxigraph::model::Term;
+use oxilangtag::LanguageTag;
+
+pub const ENGLISH_PRIMARY: &str = "en";
+
+pub static ENGLISH_OR_UNTAGGED: LazyLock<LanguageCondition> = LazyLock::new(|| {
+    LanguageCondition::ExactMatchOrUntagged(LanguageTag::parse(ENGLISH_PRIMARY.to_string()).unwrap())
+});
+
+pub enum LanguageCondition {
+    ExactMatchOnly(LanguageTag<String>),
+    ExactMatchOrUntagged(LanguageTag<String>),
+    UntaggedOnly,
+    AnyOrNone,
+}
+
+impl LanguageCondition {
+    pub fn primary_matches_term(&self, term: &Term) -> bool {
+        if let Term::Literal(literal) = term {
+            let tag = literal.language()
+                .map(LanguageTag::parse_and_normalize)
+                .and_then(Result::ok);
+
+            match (tag, self) {
+                (Some(language), LanguageCondition::ExactMatchOnly(expectation)) |
+                (Some(language), LanguageCondition::ExactMatchOrUntagged(expectation)) => language.primary_language() == expectation.primary_language(),
+                (None, LanguageCondition::ExactMatchOrUntagged(_)) => true,
+                (None, LanguageCondition::UntaggedOnly) => true,
+                (_, LanguageCondition::AnyOrNone) => true,
+                _ => false,
+            }
+        } else {
+            false
+        }
+    }
+
+    pub fn to_filter_expression(&self, var: &str) -> String {
+        match self {
+            LanguageCondition::ExactMatchOnly(language) => format!(r#"FILTER(langMATCHES(LANG(?{var}), "{language}"))"#),
+            LanguageCondition::ExactMatchOrUntagged(language) => format!(r#"FILTER(langMATCHES(LANG(?{var}), "{language}") || !hasLANG(?{var}))"#),
+            LanguageCondition::UntaggedOnly => format!("FILTER(!hasLANG(?{var}))"),
+            LanguageCondition::AnyOrNone => "".to_string(),
+        }
+    }
+}