OpenCypher Operator Implementation Status¶
Implementation status of OpenCypher operators in GraphForge.
Legend: ✅ COMPLETE | ⚠️ PARTIAL | ❌ NOT_IMPLEMENTED
Summary¶
| Category | Complete | Partial | Not Implemented | Total |
|---|---|---|---|---|
| Comparison | 8 | 0 | 0 | 8 |
| Logical | 4 | 0 | 0 | 4 |
| Arithmetic | 6 | 0 | 0 | 6 |
| String | 5 | 0 | 0 | 5 |
| List | 5 | 0 | 0 | 5 |
| Property | 1 | 0 | 0 | 1 |
| Pattern | 5 | 0 | 0 | 5 |
| TOTAL | 34 | 0 | 0 | 34 |
Overall: 34/34 operators (100%) complete
Comparison Operators¶
= (Equals) ✅¶
Status: COMPLETE
File: src/graphforge/executor/evaluator.py (binary op evaluation)
Tests: Comparison1-4.feature
<> (Not Equals) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Comparison scenarios
< (Less Than) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Comparison scenarios
> (Greater Than) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Comparison scenarios
<= (Less Than or Equal) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Comparison scenarios
>= (Greater Than or Equal) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Comparison scenarios
IS NULL ✅¶
Status: COMPLETE
File: evaluator.py (unary op evaluation)
Tests: Null handling scenarios
IS NOT NULL ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Null scenarios
Logical Operators¶
AND ✅¶
Status: COMPLETE
File: evaluator.py
Notes: Ternary logic (NULL propagation)
Tests: Boolean1-5.feature
OR ✅¶
Status: COMPLETE
File: evaluator.py
Notes: Ternary logic
Tests: Boolean scenarios
NOT ✅¶
Status: COMPLETE
File: evaluator.py
Notes: Ternary logic
Tests: Boolean scenarios
XOR ✅¶
Status: COMPLETE
File: evaluator.py
Notes: Ternary logic (NULL propagation), precedence: NOT > AND > XOR > OR
Tests: tests/integration/test_xor_operator.py, tests/unit/parser/test_parser.py
Arithmetic Operators¶
+ (Addition) ✅¶
Status: COMPLETE
File: evaluator.py
Notes: Supports numeric addition and string concatenation
Tests: Mathematical scenarios
- (Subtraction) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Mathematical scenarios
* (Multiplication) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Mathematical scenarios
/ (Division) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Mathematical scenarios
% (Modulo) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: Mathematical scenarios
^ (Power) ✅¶
Status: COMPLETE
File: evaluator.py
Notes: Right-associative (232 = 512). Highest arithmetic precedence (above , /). int^int returns int if result is whole, else float. Supports negative and fractional exponents. NULL propagation.
**Tests:* tests/integration/test_power_operator.py (39 tests)
String Operators¶
+ (Concatenation) ✅¶
Status: COMPLETE
File: evaluator.py (binary + op)
Tests: String scenarios
=~ (Regex Match) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: String pattern matching scenarios
STARTS WITH ✅¶
Status: COMPLETE
File: evaluator.py
Tests: String scenarios
ENDS WITH ✅¶
Status: COMPLETE
File: evaluator.py
Tests: String scenarios
CONTAINS ✅¶
Status: COMPLETE
File: evaluator.py
Tests: String scenarios
List Operators¶
IN (Membership) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: List scenarios
[] (Index Access) ✅¶
Status: COMPLETE
File: evaluator.py:1458 (_evaluate_subscript)
Tests: List access scenarios
+ (List Concatenation) ✅¶
Status: COMPLETE
File: evaluator.py
Tests: List scenarios
[start..end] (Slicing) ✅¶
Status: COMPLETE
File: evaluator.py:1458 (_evaluate_subscript)
Signature: list[start..end]
Tests: tests/integration/test_list_subscript.py (TestListSliceOperations)
Examples:
- RETURN [1, 2, 3, 4, 5][1..3] → [2, 3]
- RETURN [1, 2, 3][..2] → [1, 2]
- RETURN [1, 2, 3][1..] → [2, 3]
[] (Negative Indexing) ✅¶
Status: COMPLETE
File: evaluator.py:1458 (_evaluate_subscript)
Signature: list[-index] where -1 is last element, -2 is second-to-last, etc.
Tests: tests/integration/test_list_subscript.py (TestListIndexAccess)
Examples:
- RETURN [1, 2, 3][-1] → 3 (last element)
- RETURN [1, 2, 3][-2] → 2 (second-to-last)
- RETURN [1, 2, 3, 4, 5][-3..] → [3, 4, 5] (last 3 elements)
Property Access¶
. (Property Access) ✅¶
Status: COMPLETE
File: evaluator.py (PropertyAccess evaluation)
Tests: Extensive property access scenarios
Pattern Operators¶
- (Undirected Relationship) ✅¶
Status: COMPLETE
File: src/graphforge/parser/cypher.lark:115
Tests: Pattern matching scenarios
→ (Right Arrow) ✅¶
Status: COMPLETE
File: cypher.lark:117
Tests: Pattern scenarios
← (Left Arrow) ✅¶
Status: COMPLETE
File: cypher.lark:116
Tests: Pattern scenarios
-[*]- (Variable Length) ✅¶
Status: COMPLETE
File: cypher.lark:121-124
Tests: Variable-length path scenarios
: (Label Check) ✅¶
Status: COMPLETE File: Parser and executor Tests: Label matching scenarios
Implementation Notes¶
Strengths¶
- All comparison operators with proper NULL handling
- All logical operators (AND, OR, XOR, NOT) with ternary logic
- All arithmetic operators complete including power (^) with right-associativity
- All string operators including regex matching
- Pattern operators fully implemented
- Property access complete
- All list operators including slicing and negative indexing
Limitations¶
- None - all 34 operators fully implemented
References¶
- OpenCypher Specification: https://opencypher.org/resources/
- GraphForge Evaluator:
src/graphforge/executor/evaluator.py - GraphForge Grammar:
src/graphforge/parser/cypher.lark