gregfelice opened a new pull request, #2359:
URL: https://github.com/apache/age/pull/2359
## Summary
Implements the four openCypher predicate functions (issues #552, #553, #555,
#556):
- `all(x IN list WHERE predicate)` — true if all elements match
- `any(x IN list WHERE predicate)` — true if at least one matches
- `none(x IN list WHERE predicate)` — true if no elements match
- `single(x IN list WHERE predicate)` — true if exactly one matches
These are among the most requested Cypher features for AGE and are critical
for users migrating from Neo4j and Kuzu (recently archived).
## Implementation
**Approach:** Builds on the existing list comprehension infrastructure
(`unnest`-based subqueries with child parsestates for variable scoping).
**SQL transformation strategy:**
- `all()` → `NOT EXISTS (SELECT 1 FROM unnest(list) AS x WHERE NOT
predicate)`
- `any()` → `EXISTS (SELECT 1 FROM unnest(list) AS x WHERE predicate)`
- `none()` → `NOT EXISTS (SELECT 1 FROM unnest(list) AS x WHERE predicate)`
- `single()` → `(SELECT count(*) FROM unnest(list) AS x WHERE predicate) = 1`
EXISTS/NOT EXISTS short-circuits on first match for optimal performance.
**Files changed (12):**
| File | Change |
|------|--------|
| `cypher_nodes.h` | New `cypher_predicate_function` node type with
`CPFK_ALL/ANY/NONE/SINGLE` enum |
| `ag_nodes.h` / `ag_nodes.c` | Node registration |
| `cypher_outfuncs.h` / `cypher_outfuncs.c` | Serialization |
| `cypher_kwlist.h` | Three new keywords: `ANY_P`, `NONE`, `SINGLE` |
| `cypher_gram.y` | Grammar rules in `expr_func_subexpr`,
`build_predicate_function_node()` helper, `extract_iter_variable_name()` shared
helper, keywords added to `safe_keywords` |
| `cypher_clause.c` | `transform_cypher_predicate_function()` — builds query
tree from predicate node |
| `cypher_analyze.c` | Expression walker for new node type |
| `Makefile` | Register new regression test |
| `regress/sql/predicate_functions.sql` | New test file |
| `regress/expected/predicate_functions.out` | Expected output |
**Backward compatibility:**
- `ANY_P`, `NONE`, `SINGLE` added to `safe_keywords` so they work as
property keys and label names (e.g., `{any: 1, none: 2, single: 3}`)
- `ALL` was already a reserved keyword with `safe_keywords` entry
- No grammar conflicts (verified: zero new shift/reduce or reduce/reduce
warnings)
## Regression Tests
28 test queries covering:
- Basic true/false for each function
- Empty list edge cases (vacuous truth for `all()`/`none()`, false for
`any()`/`single()`)
- Graph data integration (`MATCH (u) WHERE all(x IN u.vals WHERE ...)`)
- Boolean combinations (`any(...) AND all(...)`)
- Nested predicates (`any(x IN ... WHERE all(y IN ... WHERE ...))`)
- Keyword backward compatibility (`{any: 1, none: 2, single: 3}`)
- Deterministic ordering (all graph queries use `ORDER BY`)
All 32 regression tests pass (31 existing + 1 new).
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