uqa_sql/semantics/
period.rs

1//
2// Unified Query Algebra
3//
4// Copyright (c) 2023-2026 Cognica, Inc.
5//
6
7//! Canonical range values used by temporal keys and references.
8use crate::{
9    ast::RangeSubtype,
10    expr::{parse_multirange, parse_range, CanonicalRange},
11    ColumnType, SQLError,
12};
13use uqa_core::Value;
14
15pub fn period_ranges(
16    value: &Value,
17    column_type: &ColumnType,
18) -> Result<(RangeSubtype, Vec<CanonicalRange>), SQLError> {
19    let (Value::Str(text) | Value::FixedChar(text)) = value else {
20        return Err(SQLError::TypeMismatch(format!(
21            "PERIOD value has incompatible runtime carrier {value:?}"
22        )));
23    };
24    match column_type {
25        ColumnType::Range(subtype) => {
26            let range = parse_range(text, *subtype)?;
27            Ok((
28                *subtype,
29                (!range.is_empty()).then_some(range).into_iter().collect(),
30            ))
31        }
32        ColumnType::Multirange(subtype) => Ok((
33            *subtype,
34            parse_multirange(text, *subtype)?.ranges().to_vec(),
35        )),
36        other => Err(SQLError::TypeMismatch(format!(
37            "PERIOD column must be a range or multirange, got {}",
38            other.sql_name()
39        ))),
40    }
41}
42
43pub fn period_values_overlap(
44    left: &Value,
45    right: &Value,
46    column_type: &ColumnType,
47) -> Result<bool, SQLError> {
48    let (left_subtype, left) = period_ranges(left, column_type)?;
49    let (right_subtype, right) = period_ranges(right, column_type)?;
50    Ok(left_subtype == right_subtype
51        && left
52            .iter()
53            .any(|left| right.iter().any(|right| left.overlaps(right))))
54}
uqa_sql/semantics/period.rs

uqa_sql/semantics/
period.rs
