vortex_expr/exprs/
pack.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use std::fmt::Display;
5use std::hash::Hash;
6
7use itertools::Itertools as _;
8use vortex_array::arrays::StructArray;
9use vortex_array::validity::Validity;
10use vortex_array::{ArrayRef, DeserializeMetadata, IntoArray, ProstMetadata};
11use vortex_dtype::{DType, FieldName, FieldNames, Nullability, StructFields};
12use vortex_error::{VortexExpect as _, VortexResult, vortex_bail, vortex_err};
13use vortex_proto::expr as pb;
14
15use crate::{AnalysisExpr, ExprEncodingRef, ExprId, ExprRef, IntoExpr, Scope, VTable, vtable};
16
17vtable!(Pack);
18
19/// Pack zero or more expressions into a structure with named fields.
20///
21/// # Examples
22///
23/// ```
24/// use vortex_array::{IntoArray, ToCanonical};
25/// use vortex_buffer::buffer;
26/// use vortex_expr::{root, PackExpr, Scope, VortexExpr};
27/// use vortex_scalar::Scalar;
28/// use vortex_dtype::Nullability;
29///
30/// let example = PackExpr::try_new(
31///     ["x", "x copy", "second x copy"].into(),
32///     vec![root(), root(), root()],
33///     Nullability::NonNullable,
34/// ).unwrap();
35/// let packed = example.evaluate(&Scope::new(buffer![100, 110, 200].into_array())).unwrap();
36/// let x_copy = packed
37///     .to_struct()
38///     .unwrap()
39///     .field_by_name("x copy")
40///     .unwrap()
41///     .clone();
42/// assert_eq!(x_copy.scalar_at(0).unwrap(), Scalar::from(100));
43/// assert_eq!(x_copy.scalar_at(1).unwrap(), Scalar::from(110));
44/// assert_eq!(x_copy.scalar_at(2).unwrap(), Scalar::from(200));
45/// ```
46///
47#[allow(clippy::derived_hash_with_manual_eq)]
48#[derive(Debug, Clone, PartialEq, Eq, Hash)]
49pub struct PackExpr {
50    names: FieldNames,
51    values: Vec<ExprRef>,
52    nullability: Nullability,
53}
54
55pub struct PackExprEncoding;
56
57impl VTable for PackVTable {
58    type Expr = PackExpr;
59    type Encoding = PackExprEncoding;
60    type Metadata = ProstMetadata<pb::PackOpts>;
61
62    fn id(_encoding: &Self::Encoding) -> ExprId {
63        ExprId::new_ref("pack")
64    }
65
66    fn encoding(_expr: &Self::Expr) -> ExprEncodingRef {
67        ExprEncodingRef::new_ref(PackExprEncoding.as_ref())
68    }
69
70    fn metadata(expr: &Self::Expr) -> Option<Self::Metadata> {
71        Some(ProstMetadata(pb::PackOpts {
72            paths: expr.names.iter().map(|n| n.to_string()).collect(),
73            nullable: expr.nullability.into(),
74        }))
75    }
76
77    fn children(expr: &Self::Expr) -> Vec<&ExprRef> {
78        expr.values.iter().collect()
79    }
80
81    fn with_children(expr: &Self::Expr, children: Vec<ExprRef>) -> VortexResult<Self::Expr> {
82        PackExpr::try_new(expr.names.clone(), children, expr.nullability)
83    }
84
85    fn build(
86        _encoding: &Self::Encoding,
87        metadata: &<Self::Metadata as DeserializeMetadata>::Output,
88        children: Vec<ExprRef>,
89    ) -> VortexResult<Self::Expr> {
90        if children.len() != metadata.paths.len() {
91            vortex_bail!(
92                "Pack expression expects {} children, got {}",
93                metadata.paths.len(),
94                children.len()
95            );
96        }
97        let names: FieldNames = metadata
98            .paths
99            .iter()
100            .map(|name| FieldName::from(name.as_str()))
101            .collect();
102        PackExpr::try_new(names, children, metadata.nullable.into())
103    }
104
105    fn evaluate(expr: &Self::Expr, scope: &Scope) -> VortexResult<ArrayRef> {
106        let len = scope.len();
107        let value_arrays = expr
108            .values
109            .iter()
110            .map(|value_expr| value_expr.unchecked_evaluate(scope))
111            .process_results(|it| it.collect::<Vec<_>>())?;
112        let validity = match expr.nullability {
113            Nullability::NonNullable => Validity::NonNullable,
114            Nullability::Nullable => Validity::AllValid,
115        };
116        Ok(StructArray::try_new(expr.names.clone(), value_arrays, len, validity)?.into_array())
117    }
118
119    fn return_dtype(expr: &Self::Expr, scope: &DType) -> VortexResult<DType> {
120        let value_dtypes = expr
121            .values
122            .iter()
123            .map(|value_expr| value_expr.return_dtype(scope))
124            .process_results(|it| it.collect())?;
125        Ok(DType::Struct(
126            StructFields::new(expr.names.clone(), value_dtypes),
127            expr.nullability,
128        ))
129    }
130}
131
132impl PackExpr {
133    pub fn try_new(
134        names: FieldNames,
135        values: Vec<ExprRef>,
136        nullability: Nullability,
137    ) -> VortexResult<Self> {
138        if names.len() != values.len() {
139            vortex_bail!("length mismatch {} {}", names.len(), values.len());
140        }
141        Ok(PackExpr {
142            names,
143            values,
144            nullability,
145        })
146    }
147
148    pub fn try_new_expr(
149        names: FieldNames,
150        values: Vec<ExprRef>,
151        nullability: Nullability,
152    ) -> VortexResult<ExprRef> {
153        Self::try_new(names, values, nullability).map(|v| v.into_expr())
154    }
155
156    pub fn names(&self) -> &FieldNames {
157        &self.names
158    }
159
160    pub fn field(&self, field_name: &FieldName) -> VortexResult<ExprRef> {
161        let idx = self
162            .names
163            .iter()
164            .position(|name| name == field_name)
165            .ok_or_else(|| {
166                vortex_err!(
167                    "Cannot find field {} in pack fields {:?}",
168                    field_name,
169                    self.names
170                )
171            })?;
172
173        self.values
174            .get(idx)
175            .cloned()
176            .ok_or_else(|| vortex_err!("field index out of bounds: {}", idx))
177    }
178
179    pub fn nullability(&self) -> Nullability {
180        self.nullability
181    }
182}
183
184pub fn pack(
185    elements: impl IntoIterator<Item = (impl Into<FieldName>, ExprRef)>,
186    nullability: Nullability,
187) -> ExprRef {
188    let (names, values): (Vec<_>, Vec<_>) = elements
189        .into_iter()
190        .map(|(name, value)| (name.into(), value))
191        .unzip();
192    PackExpr::try_new(names.into(), values, nullability)
193        .vortex_expect("pack names and values have the same length")
194        .into_expr()
195}
196
197impl Display for PackExpr {
198    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
199        write!(
200            f,
201            "pack({}){}",
202            self.names
203                .iter()
204                .zip(&self.values)
205                .format_with(", ", |(name, expr), f| f(&format_args!("{name}: {expr}"))),
206            self.nullability
207        )
208    }
209}
210
211impl AnalysisExpr for PackExpr {}
212
213#[cfg(test)]
214mod tests {
215
216    use vortex_array::arrays::{PrimitiveArray, StructArray};
217    use vortex_array::validity::Validity;
218    use vortex_array::vtable::ValidityHelper;
219    use vortex_array::{Array, ArrayRef, IntoArray, ToCanonical};
220    use vortex_buffer::buffer;
221    use vortex_dtype::{FieldNames, Nullability};
222    use vortex_error::{VortexResult, vortex_bail};
223
224    use crate::{IntoExpr, PackExpr, Scope, col};
225
226    fn test_array() -> ArrayRef {
227        StructArray::from_fields(&[
228            ("a", buffer![0, 1, 2].into_array()),
229            ("b", buffer![4, 5, 6].into_array()),
230        ])
231        .unwrap()
232        .into_array()
233    }
234
235    fn primitive_field(array: &dyn Array, field_path: &[&str]) -> VortexResult<PrimitiveArray> {
236        let mut field_path = field_path.iter();
237
238        let Some(field) = field_path.next() else {
239            vortex_bail!("empty field path");
240        };
241
242        let mut array = array.to_struct()?.field_by_name(field)?.clone();
243        for field in field_path {
244            array = array.to_struct()?.field_by_name(field)?.clone();
245        }
246        Ok(array.to_primitive().unwrap())
247    }
248
249    #[test]
250    pub fn test_empty_pack() {
251        let expr =
252            PackExpr::try_new(FieldNames::default(), Vec::new(), Nullability::NonNullable).unwrap();
253
254        let test_array = test_array();
255        let actual_array = expr.evaluate(&Scope::new(test_array.clone())).unwrap();
256        assert_eq!(actual_array.len(), test_array.len());
257        assert_eq!(
258            actual_array.to_struct().unwrap().struct_fields().nfields(),
259            0
260        );
261    }
262
263    #[test]
264    pub fn test_simple_pack() {
265        let expr = PackExpr::try_new(
266            ["one", "two", "three"].into(),
267            vec![col("a"), col("b"), col("a")],
268            Nullability::NonNullable,
269        )
270        .unwrap();
271
272        let actual_array = expr
273            .evaluate(&Scope::new(test_array()))
274            .unwrap()
275            .to_struct()
276            .unwrap();
277        let expected_names: FieldNames = ["one", "two", "three"].into();
278        assert_eq!(actual_array.names(), &expected_names);
279        assert_eq!(actual_array.validity(), &Validity::NonNullable);
280
281        assert_eq!(
282            primitive_field(actual_array.as_ref(), &["one"])
283                .unwrap()
284                .as_slice::<i32>(),
285            [0, 1, 2]
286        );
287        assert_eq!(
288            primitive_field(actual_array.as_ref(), &["two"])
289                .unwrap()
290                .as_slice::<i32>(),
291            [4, 5, 6]
292        );
293        assert_eq!(
294            primitive_field(actual_array.as_ref(), &["three"])
295                .unwrap()
296                .as_slice::<i32>(),
297            [0, 1, 2]
298        );
299    }
300
301    #[test]
302    pub fn test_nested_pack() {
303        let expr = PackExpr::try_new(
304            ["one", "two", "three"].into(),
305            vec![
306                col("a"),
307                PackExpr::try_new(
308                    ["two_one", "two_two"].into(),
309                    vec![col("b"), col("b")],
310                    Nullability::NonNullable,
311                )
312                .unwrap()
313                .into_expr(),
314                col("a"),
315            ],
316            Nullability::NonNullable,
317        )
318        .unwrap();
319
320        let actual_array = expr
321            .evaluate(&Scope::new(test_array()))
322            .unwrap()
323            .to_struct()
324            .unwrap();
325        let expected_names = FieldNames::from(["one", "two", "three"]);
326        assert_eq!(actual_array.names(), &expected_names);
327
328        assert_eq!(
329            primitive_field(actual_array.as_ref(), &["one"])
330                .unwrap()
331                .as_slice::<i32>(),
332            [0, 1, 2]
333        );
334        assert_eq!(
335            primitive_field(actual_array.as_ref(), &["two", "two_one"])
336                .unwrap()
337                .as_slice::<i32>(),
338            [4, 5, 6]
339        );
340        assert_eq!(
341            primitive_field(actual_array.as_ref(), &["two", "two_two"])
342                .unwrap()
343                .as_slice::<i32>(),
344            [4, 5, 6]
345        );
346        assert_eq!(
347            primitive_field(actual_array.as_ref(), &["three"])
348                .unwrap()
349                .as_slice::<i32>(),
350            [0, 1, 2]
351        );
352    }
353
354    #[test]
355    pub fn test_pack_nullable() {
356        let expr = PackExpr::try_new(
357            ["one", "two", "three"].into(),
358            vec![col("a"), col("b"), col("a")],
359            Nullability::Nullable,
360        )
361        .unwrap();
362
363        let actual_array = expr
364            .evaluate(&Scope::new(test_array()))
365            .unwrap()
366            .to_struct()
367            .unwrap();
368        let expected_names: FieldNames = ["one", "two", "three"].into();
369        assert_eq!(actual_array.names(), &expected_names);
370        assert_eq!(actual_array.validity(), &Validity::AllValid);
371    }
372}
vortex_expr/exprs/pack.rs

vortex_expr/exprs/
pack.rs
