Traversal and Coordination Katas

Attempt before opening the separate practice feedback. Keep a prediction, observed result, explanation and changed-assumption case.

P16: Lazy traversal

A source returns (10,20), then an empty nonfinal page, then (30). Predict fetch calls after construction and after each next. Stop after 20 and explain why later pages must not have been fetched. Complete L05.

P17: Terminal policy

Compare first-match pass/allow/deny with a pipeline where all mandatory checks must pass. Trace authentication success followed by payload rejection. Include all-pass, empty, invalid-result and exception cases. Complete L06.

P18: Visitor edit surface

Evaluate and print (2+3)*4. Add a Count operation, then a Neg node. Record which files/methods change and why a default visitor method could hide incompleteness. Complete L07.

P19: Mediator truth table

Using lesson 17, enumerate local/abroad, pickup/post, empty/nonempty address: eight combinations. Show selected method, required-address and submit state. Identify one feedback loop and one stale asynchronous response.

P20: Small interpreter

Using lesson 18 grammar semantics, implement evaluation of tuple ASTs for lit/name/and/or/not without eval. Enumerate truth tables and test unknown names on taken/untaken branches. Set a depth limit for your extension and reject unsupported nodes explicitly.

Submit actual errors and repairs, not a quota. Reuse lab evidence where applicable. See contracts and assessment.