The document discusses tree editing using zippers. It describes a zipper node protocol for navigating a tree structure with records and fields holding child nodes. The document provides examples of using a record zipper to apply tree pattern matching and evaluation rules to transform trees, such as rewriting a comparison operation tree into an equivalent form. It also briefly mentions Revelytix's use of zippers to translate SPARQL queries to SQL.

1. Tree Editing with
Zippers
Alex Miller
Revelytix
aka @puredanger
aka “Dr. Strange Loop”

2. Zipper node protocol

3. Some records

4. Two “child” variants
seq of records
fields holding records

5. Use the record zipper
Comparison
:op := :left :right
ScalarFunction
:f :+ :exprs
ScalarFunction
:f :- :exprs
2 3 6 1
“(2 + 3) = (6 - 1)”

6. Use the record zipper
Comparison
:op := :left :right
ScalarFunction
:f :+ :exprs
ScalarFunction
:f :- :exprs
2 3 6 1
“(2 + 3) = (6 - 1)”

7. Use the record zipper
Comparison
:op := :left :right
ScalarFunction
:f :+ :exprs
ScalarFunction
:f :- :exprs
2 3 6 1
“(2 + 3) = (6 - 1)”

8. Use the record zipper
Comparison
:op := :left :right
ScalarFunction
:f :+ :exprs
ScalarFunction
:f :- :exprs
2 3 6 1
“(2 + 3) = (6 - 1)”

9. Tree pattern mutator

10. Apply evaluation rule
Comparison
:op := :left :right
ScalarFunction
:f :- :exprs
5
6 1
Comparison
:op := :left :right
5 5

11. Revelytix
• Data integration using semantic web
• SPARQL -> SQL translation
• SPARQL federation
• Business rules engine
• Emergent analytics

12. SPARQL to SQL
Parse, translate to
SPARQL algebra
Plan using
mapping
Optimize plan
Generate SQL
SELECT ?Person ?Name
WHERE {
?Person <http://domain/Person/Name> ?name
}
SPARQL algebra tree
SQL query plan
SELECT 'http://domain/Person/' || ID, Name
FROM People
SQL query plan
tree rules