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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 std::fmt::{self, Display, Formatter};
19
20use datafusion::logical_expr::expr::Alias;
21use pyo3::prelude::*;
22
23use crate::expr::PyExpr;
24
25#[pyclass(
26    from_py_object,
27    frozen,
28    name = "Alias",
29    module = "datafusion.expr",
30    subclass
31)]
32#[derive(Clone)]
33pub struct PyAlias {
34    alias: Alias,
35}
36
37impl From<Alias> for PyAlias {
38    fn from(alias: Alias) -> Self {
39        Self { alias }
40    }
41}
42
43impl From<PyAlias> for Alias {
44    fn from(py_alias: PyAlias) -> Self {
45        py_alias.alias
46    }
47}
48
49impl Display for PyAlias {
50    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
51        write!(
52            f,
53            "Alias
54            \nExpr: `{:?}`
55            \nAlias Name: `{}`",
56            &self.alias.expr, &self.alias.name
57        )
58    }
59}
60
61#[pymethods]
62impl PyAlias {
63    /// Retrieve the "name" of the alias
64    fn alias(&self) -> PyResult<String> {
65        Ok(self.alias.name.clone())
66    }
67
68    fn expr(&self) -> PyResult<PyExpr> {
69        Ok((*self.alias.expr.clone()).into())
70    }
71
72    /// Get a String representation of this column
73    fn __repr__(&self) -> String {
74        format!("{self}")
75    }
76}