PART I
Warm-up
Reconnect with a useful idea before starting plan safe lifecycle and destruction. In one or two sentences, describe the input, output or host boundary from the previous exercise that this lesson builds on. If you are arriving directly, skim the worked example first; there is no locked prerequisite.
A rough note is enough. You can revise it after the example.
PART II
Instruction & guided example
Repair double destruction assumptions
An extension platform separates the script’s intent from native-service implementation, public compatibility promises, caller-scoped authorization and owner lifetimes. Those boundaries require explicit host contracts; import visibility does not establish resource permission or execution.
Supplied fixture: Two completion paths both request disposal of the same resource. Host duplicate-disposal behavior is unspecified.
The design needs an at-most-once owner transition or an explicitly idempotent host disposal contract. Assuming double disposal is harmless is unsupported; assuming it always crashes is equally unsupported. Record the state transition and required host evidence.
The source anchor below is illustrative. WillowScript, its object/anonymous-function extensions and native libraries remain proposed/unimplemented here. Application and data symbols are exercise-host inputs. State missing signatures or recovery guarantees as requirements; do not invent transaction, cancellation or restore methods and do not claim these paper traces executed.
Worked reasoning and supplied artifact
// PAPER FIXTURE — Repair double destruction assumptions
// Manual worked artifact; comments below are not executable source.
// INPUT / CONTRACT: Supplied fixture: Two completion paths both request disposal of the same resource. Host
// duplicate-disposal behavior is unspecified.
// DERIVATION / EXPECTED ARTIFACT: The design needs an at-most-once owner transition or an explicitly
// idempotent host disposal contract. Assuming double disposal is harmless is unsupported; assuming it
// always crashes is equally unsupported. Record the state transition and required host evidence.Illustrative example from the proposed WillowScript design. The language and WUIX/WMATH/WDB/WAUDIO/WTMP services are not implemented in the supplied source. This site has no interpreter, VM or native host and does not execute or certify the snippet.
Walk through the example, one line at a time
// PAPER FIXTURE — Repair double destruction assumptionsThis comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
// Manual worked artifact; comments below are not executable source.This comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
// INPUT / CONTRACT: Supplied fixture: Two completion paths both request disposal of the same resource. HostThis comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
// duplicate-disposal behavior is unspecified.This comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
// DERIVATION / EXPECTED ARTIFACT: The design needs an at-most-once owner transition or an explicitlyThis comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
// idempotent host disposal contract. Assuming double disposal is harmless is unsupported; assuming itThis comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
// always crashes is equally unsupported. Record the state transition and required host evidence.This comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
Try the guided change
Guided work: reproduce the fixture as a state/operation ledger and identify the exact evidence boundary supporting its conclusion.
- Write the supplied inputs and initial state before following the example.
- Reconstruct each intermediate calculation or host decision, then compare with the worked artifact.
- Explain why the contrasting alternative fails before attempting the changed inputs in Part IV.
PART III
Take a breather
Step back after the guided example. Look away from the screen, stretch, or reread your prediction. This is an optional learning pause, not a timer or an assessment gate.
When you return, try to name the lesson’s key idea without copying its wording. If that feels difficult, return to Part II and trace one line rather than restarting the entire lesson.
PART IV
Independent practice
Project context: Versioned extension architecture. Build a small, understandable change around plan safe lifecycle and destruction.
Produce live→disposing→disposed states and concurrent completion events in both orders. Use different disposable record/resource identities from the worked fixture. Supply intended invariant, step-by-step normal trace, contrasting failed trace, final state and unresolved host requirements.
What to produce
Produce live→disposing→disposed states and concurrent completion events in both orders. Include explicit inputs, intermediate states, correct final artifacts and acceptance criteria.
- State the intended behavior in a sentence before editing.
- Use only source-backed syntax and the host services whose contract you have been given.
- Record a normal case and a boundary or unavailable-resource case.
- Label hand predictions separately from anything actually measured in a supplied toolchain.
Syntax colors are a reading aid, not a compiler. The line you are editing stays uncolored until you move to a different line; capitalization is never changed. Drafts stay on this browser and code is not executed.
Need a hint?
The design needs an at-most-once owner transition or an explicitly idempotent host disposal contract. Assuming double disposal is harmless is unsupported; assuming it always crashes is equally unsupported. Record the state transition and required host evidence.
The rejected conclusion “That duplicates are always harmless” exceeds or violates the stated contract. The design needs an at-most-once owner transition or an explicitly idempotent host disposal contract. Assuming double disposal is harmless is unsupported; assuming it always crashes is equally unsupported. Record the state transition and required host evidence.
Original learning-path task and reference
In a classroom scheduling assistant, demonstrate plan safe lifecycle and destruction. Explain the flash answer, locate a plausible mistake, and repair the relevant part of your task. Include .ws source and a host-resource contract; compare at least one normal case and one edge case.
import wuix.widget;
import app;
domain Workspace {
const application = Application({
name: "Workspace",
window: { title: "Dashboard", size: [1280, 800] },
events: {
"app.ready": fnc() -> void { console.log("Ready"); }
}
});
}Where the original task needs a host API that is not supplied here, write the contract and predictions. Do not invent a runtime result.
PART V
Self-check
Use this check to notice what to revisit. It does not award a private course grade, block another page or claim to verify compiled code. Every answer has a learning explanation.
You may keep exploring even if you are unsure. Use the hint, compare the trace, and revise your explanation.
PART VI
Recap & small task
Bring the idea back to the mod feature you are building. A useful recap connects the mechanism to a decision you can make in your own code.
- Repair double destruction assumptions
- Two completion paths both request disposal of the same resource. Host duplicate-disposal behavior is unspecified.
- Separate source-backed behavior, host requirements and untested predictions.
One small recap task
Change one timing, permission, version or ownership condition in the supplied fixture. State which final artifact changes and which invariant must remain preserved.
This marks your personal practice record only. It is not a certification or an official workspace assessment.
