Method register_udf

datafusion/expr/src/registry.rs:243–245

(&mut self, udf: Arc<ScalarUDF>)

    }

    fn register_udf(&mut self, udf: Arc<ScalarUDF>) -> Result<Option<Arc<ScalarUDF>>> {
        Ok(self.udfs.insert(udf.name().to_string(), udf))
    }
    fn register_higher_order_function(
        &mut self,
        function: Arc<HigherOrderUDF>,