rdf_fusion_functions/scalar/numeric/
rand.rs

1use crate::scalar::sparql_op_impl::{
2    ScalarSparqlOpImpl, create_typed_value_sparql_op_impl,
3};
4use crate::scalar::{ScalarSparqlOp, ScalarSparqlOpSignature, SparqlOpArity};
5use datafusion::logical_expr::{ColumnarValue, Volatility};
6use rand::Rng;
7use rdf_fusion_encoding::typed_value::TypedValueEncoding;
8use rdf_fusion_encoding::typed_value::encoders::DefaultTypedValueEncoder;
9use rdf_fusion_encoding::{EncodingArray, TermEncoder};
10use rdf_fusion_extensions::functions::BuiltinName;
11use rdf_fusion_extensions::functions::FunctionName;
12use rdf_fusion_model::{Numeric, TypedValueRef};
13
14#[derive(Debug, Hash, PartialEq, Eq)]
15pub struct RandSparqlOp;
16
17impl Default for RandSparqlOp {
18    fn default() -> Self {
19        Self::new()
20    }
21}
22
23impl RandSparqlOp {
24    const NAME: FunctionName = FunctionName::Builtin(BuiltinName::Rand);
25
26    pub fn new() -> Self {
27        Self {}
28    }
29}
30
31impl ScalarSparqlOp for RandSparqlOp {
32    fn name(&self) -> &FunctionName {
33        &Self::NAME
34    }
35
36    fn signature(&self) -> ScalarSparqlOpSignature {
37        ScalarSparqlOpSignature {
38            volatility: Volatility::Volatile,
39            arity: SparqlOpArity::Nullary,
40        }
41    }
42
43    fn typed_value_encoding_op(
44        &self,
45    ) -> Option<Box<dyn ScalarSparqlOpImpl<TypedValueEncoding>>> {
46        Some(create_typed_value_sparql_op_impl(|args| {
47            let mut rng = rand::rng();
48            let values = (0..args.number_rows).map(|_| {
49                let value = rng.random::<f64>();
50                Ok(TypedValueRef::NumericLiteral(Numeric::Double(value.into())))
51            });
52            let array = DefaultTypedValueEncoder::encode_terms(values)?;
53            Ok(ColumnarValue::Array(array.into_array()))
54        }))
55    }
56}