Function registry

datafusion/core/tests/dataframe/mod.rs:1645–1675

()

#[tokio::test]
async fn registry() -> Result<()> {
    let ctx = SessionContext::new();
    register_aggregate_csv(&ctx, "aggregate_test_100").await?;

    // declare the udf
    let my_fn: ScalarFunctionImplementation =
        Arc::new(|_: &[ColumnarValue]| unimplemented!("my_fn is not implemented"));

    // create and register the udf
    ctx.register_udf(create_udf(
        "my_fn",
        vec![DataType::Float64],
        DataType::Float64,
        Volatility::Immutable,
        my_fn,
    ));

    // build query with a UDF using DataFrame API
    let df = ctx.table("aggregate_test_100").await?;

    let expr = df.registry().udf("my_fn")?.call(vec![col("c12")]);
    let df = df.select(vec![expr])?;

    // build query using SQL
    let sql_plan = ctx.sql("SELECT my_fn(c12) FROM aggregate_test_100").await?;

    // the two plans should be identical
    assert_same_plan(df.logical_plan(), sql_plan.logical_plan());

    Ok(())
}

#[tokio::test]
async fn sendable() {