buraksenn commented on code in PR #13201:
URL: https://github.com/apache/datafusion/pull/13201#discussion_r1835784521
##########
datafusion/expr/src/built_in_window_function.rs:
##########
@@ -17,115 +17,12 @@
//! Built-in functions module contains all the built-in functions definitions.
-use std::fmt;
-use std::str::FromStr;
-
-use crate::type_coercion::functions::data_types;
-use crate::utils;
-use crate::{Signature, Volatility};
-use datafusion_common::{plan_datafusion_err, plan_err, DataFusionError,
Result};
-
-use arrow::datatypes::DataType;
-
use strum_macros::EnumIter;
-impl fmt::Display for BuiltInWindowFunction {
- fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
- write!(f, "{}", self.name())
- }
-}
-
/// A [window function] built in to DataFusion
///
/// [Window Function]: https://en.wikipedia.org/wiki/Window_function_(SQL)
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Hash, EnumIter)]
pub enum BuiltInWindowFunction {
- /// returns value evaluated at the row that is the first row of the window
frame
- FirstValue,
- /// Returns value evaluated at the row that is the last row of the window
frame
- LastValue,
- /// Returns value evaluated at the row that is the nth row of the window
frame (counting from 1); returns null if no such row
- NthValue,
-}
-
-impl BuiltInWindowFunction {
- pub fn name(&self) -> &str {
- use BuiltInWindowFunction::*;
- match self {
- FirstValue => "first_value",
- LastValue => "last_value",
- NthValue => "NTH_VALUE",
- }
- }
-}
-
-impl FromStr for BuiltInWindowFunction {
- type Err = DataFusionError;
- fn from_str(name: &str) -> Result<BuiltInWindowFunction> {
- Ok(match name.to_uppercase().as_str() {
- "FIRST_VALUE" => BuiltInWindowFunction::FirstValue,
- "LAST_VALUE" => BuiltInWindowFunction::LastValue,
- "NTH_VALUE" => BuiltInWindowFunction::NthValue,
- _ => return plan_err!("There is no built-in window function named
{name}"),
- })
- }
-}
-
-/// Returns the datatype of the built-in window function
-impl BuiltInWindowFunction {
- pub fn return_type(&self, input_expr_types: &[DataType]) ->
Result<DataType> {
- // Note that this function *must* return the same type that the
respective physical expression returns
- // or the execution panics.
-
- // Verify that this is a valid set of data types for this function
- data_types(input_expr_types, &self.signature())
- // Original errors are all related to wrong function signature
- // Aggregate them for better error message
- .map_err(|_| {
- plan_datafusion_err!(
- "{}",
- utils::generate_signature_error_msg(
- &format!("{self}"),
- self.signature(),
- input_expr_types,
- )
- )
- })?;
-
- match self {
- BuiltInWindowFunction::FirstValue
- | BuiltInWindowFunction::LastValue
- | BuiltInWindowFunction::NthValue =>
Ok(input_expr_types[0].clone()),
- }
- }
-
- /// The signatures supported by the built-in window function `fun`.
- pub fn signature(&self) -> Signature {
- // Note: The physical expression must accept the type returned by this
function or the execution panics.
- match self {
- BuiltInWindowFunction::FirstValue |
BuiltInWindowFunction::LastValue => {
- Signature::any(1, Volatility::Immutable)
- }
- BuiltInWindowFunction::NthValue => Signature::any(2,
Volatility::Immutable),
- }
- }
-}
-
-#[cfg(test)]
-mod tests {
- use super::*;
- use strum::IntoEnumIterator;
- #[test]
- // Test for BuiltInWindowFunction's Display and from_str() implementations.
- // For each variant in BuiltInWindowFunction, it converts the variant to a
string
- // and then back to a variant. The test asserts that the original variant
and
- // the reconstructed variant are the same. This assertion is also
necessary for
- // function suggestion. See
https://github.com/apache/datafusion/issues/8082
- fn test_display_and_from_str() {
- for func_original in BuiltInWindowFunction::iter() {
- let func_name = func_original.to_string();
- let func_from_str =
BuiltInWindowFunction::from_str(&func_name).unwrap();
- assert_eq!(func_from_str, func_original);
- }
- }
Review Comment:
added
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org
For additional commands, e-mail: github-h...@datafusion.apache.org
