rdf_fusion_functions/scalar/terms/
lang.rs

1use crate::scalar::dispatch::dispatch_unary_owned_typed_value;
2use crate::scalar::sparql_op_impl::{
3    ScalarSparqlOpImpl, create_typed_value_sparql_op_impl,
4};
5use crate::scalar::{ScalarSparqlOp, ScalarSparqlOpSignature, SparqlOpArity};
6use rdf_fusion_encoding::typed_value::TypedValueEncoding;
7use rdf_fusion_extensions::functions::BuiltinName;
8use rdf_fusion_extensions::functions::FunctionName;
9use rdf_fusion_model::{SimpleLiteral, ThinError, TypedValue, TypedValueRef};
10
11#[derive(Debug, Hash, PartialEq, Eq)]
12pub struct LangSparqlOp;
13
14impl Default for LangSparqlOp {
15    fn default() -> Self {
16        Self::new()
17    }
18}
19
20impl LangSparqlOp {
21    const NAME: FunctionName = FunctionName::Builtin(BuiltinName::Lang);
22
23    pub fn new() -> Self {
24        Self {}
25    }
26}
27
28impl ScalarSparqlOp for LangSparqlOp {
29    fn name(&self) -> &FunctionName {
30        &Self::NAME
31    }
32
33    fn signature(&self) -> ScalarSparqlOpSignature {
34        ScalarSparqlOpSignature::default_with_arity(SparqlOpArity::Fixed(1))
35    }
36
37    fn typed_value_encoding_op(
38        &self,
39    ) -> Option<Box<dyn ScalarSparqlOpImpl<TypedValueEncoding>>> {
40        Some(create_typed_value_sparql_op_impl(|args| {
41            dispatch_unary_owned_typed_value(
42                &args.args[0],
43                |value| {
44                    let result = match value {
45                        TypedValueRef::NamedNode(_) | TypedValueRef::BlankNode(_) => {
46                            return ThinError::expected();
47                        }
48                        TypedValueRef::LanguageStringLiteral(value) => value.language,
49                        _ => "",
50                    };
51                    Ok(TypedValue::SimpleLiteral(SimpleLiteral {
52                        value: result.to_owned(),
53                    }))
54                },
55                ThinError::expected,
56            )
57        }))
58    }
59}
rdf_fusion_functions/scalar/terms/lang.rs

rdf_fusion_functions/scalar/terms/
lang.rs
