datafusion_python/expr/
alias.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use crate::expr::PyExpr;
19use pyo3::prelude::*;
20use std::fmt::{self, Display, Formatter};
21
22use datafusion::logical_expr::expr::Alias;
23
24#[pyclass(name = "Alias", module = "datafusion.expr", subclass)]
25#[derive(Clone)]
26pub struct PyAlias {
27    alias: Alias,
28}
29
30impl From<Alias> for PyAlias {
31    fn from(alias: Alias) -> Self {
32        Self { alias }
33    }
34}
35
36impl From<PyAlias> for Alias {
37    fn from(py_alias: PyAlias) -> Self {
38        py_alias.alias
39    }
40}
41
42impl Display for PyAlias {
43    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
44        write!(
45            f,
46            "Alias
47            \nExpr: `{:?}`
48            \nAlias Name: `{}`",
49            &self.alias.expr, &self.alias.name
50        )
51    }
52}
53
54#[pymethods]
55impl PyAlias {
56    /// Retrieve the "name" of the alias
57    fn alias(&self) -> PyResult<String> {
58        Ok(self.alias.name.clone())
59    }
60
61    fn expr(&self) -> PyResult<PyExpr> {
62        Ok((*self.alias.expr.clone()).into())
63    }
64
65    /// Get a String representation of this column
66    fn __repr__(&self) -> String {
67        format!("{}", self)
68    }
69}