Module op 

Algebraic Query Operators

Jena-inspired operator tree representing query algebra.

Operator Hierarchy

Op
├── OpBGP           - Basic Graph Pattern (triple patterns)
├── OpTriple        - Single triple pattern
├── OpJoin          - Join two operators
├── OpLeftJoin      - Left outer join (OPTIONAL)
├── OpFilter        - Filter with expression
├── OpUnion         - Union of two operators
├── OpProject       - Select variables
├── OpDistinct      - Remove duplicates
├── OpReduced       - Remove adjacent duplicates
├── OpSlice         - Offset and limit
├── OpOrder         - Sort results
├── OpGroup         - Group by with aggregation
├── OpExtend        - Assign expression to variable
├── OpMinus         - Set difference
├── OpTable         - Inline data
├── OpSequence      - Sequential execution
├── OpDisjunction   - OR pattern
└── OpNull          - Empty pattern

Structs

OpBGP

Basic Graph Pattern - set of triple patterns

OpCrossJoin

Cross join (Cartesian product)

OpDisjunction

Disjunction operator (OR patterns)

OpDistinct

Distinct operator

OpExtend

Extend operator (bind expression to variable)

OpFilter

Filter operator

OpGroup

Group operator

OpIntersect

Intersect operator (set intersection)

OpJoin

Join two operators

OpLeftJoin

Left outer join (OPTIONAL)

OpMinus

Minus operator (set difference)

OpNull

Null operator (empty pattern)

OpOrder

Order operator

OpProject

Project operator

OpReduced

Reduced operator (adjacent duplicate removal)

OpRightJoin

Right outer join

OpSequence

Sequence operator

OpSlice

Slice operator (offset/limit)

OpTable

Table operator (inline data VALUES)

OpTriple

Single triple pattern

OpUnion

Union operator

OrderKey

Order key

Triple

Triple pattern for graph matching

Enums

Aggregate

Aggregate function

ExprTerm

Expression term

FilterExpr

Filter expression for filtering bindings

Op

Core algebraic operator type

Pattern

Pattern element (variable or concrete value)