.

publish/src/rdf/conversion.rs

@@ -1,9 +1,37 @@
 use oxigraph::model::{NamedNode, Quad, Term};
 use oxigraph::model::vocab::{rdf, xsd};
-use tracing::info;
+use oxilangtag::LanguageTag;
 
-pub fn quad_to_term(quad: &Quad) -> &Term {
-    &quad.object
+pub enum LanguageCondition {
+    ExactMatch(LanguageTag<String>),
+    RelaxedMatch(LanguageTag<String>),
+    Untagged,
+}
+
+pub fn quad_into_term(quad: Quad) -> Term {
+    quad.object
+}
+
+pub fn english() -> LanguageCondition {
+    LanguageCondition::RelaxedMatch(LanguageTag::parse("en".to_string()).unwrap())
+}
+
+pub fn language_matches(term: &Term, condition: &LanguageCondition) -> bool {
+    if let Term::Literal(literal) = term {
+        let tag = literal.language()
+            .map(LanguageTag::parse_and_normalize)
+            .and_then(Result::ok);
+
+        match (tag, condition) {
+            (Some(language), LanguageCondition::ExactMatch(expectation)) |
+            (Some(language), LanguageCondition::RelaxedMatch(expectation)) => language == *expectation,
+            (None, LanguageCondition::RelaxedMatch(_)) => true,
+            (None, LanguageCondition::Untagged) => true,
+            _ => false,
+        }
+    } else {
+        false
+    }
 }
 
 pub fn term_to_named_node(term: &Term) -> Option<&NamedNode> {
@@ -14,7 +42,11 @@ pub fn term_to_named_node(term: &Term) -> Option<&NamedNode> {
     }
 }
 
-pub fn term_to_string(term: &Term) -> Option<&str> {
+pub fn term_into_string(term: Term) -> Option<String> {
+    term_as_str(&term).map(String::from)
+}
+
+pub fn term_as_str(term: &Term) -> Option<&str> {
     if let Term::Literal(literal) = term {
         match literal.datatype() {
             xsd::STRING | xsd::NORMALIZED_STRING | rdf::LANG_STRING | rdf::DIR_LANG_STRING => {