Type Definition datafusion_expr::ScalarFunctionImplementation

pub type ScalarFunctionImplementation = Arc<dyn Fn(&[ColumnarValue]) -> Result<ColumnarValue> + Send + Sync>;

Scalar function

The Fn param is the wrapped function but be aware that the function will be passed with the slice / vec of columnar values (either scalar or array) with the exception of zero param function, where a singular element vec will be passed. In that case the single element is a null array to indicate the batch’s row count (so that the generative zero-argument function can know the result array size).