Specify bounded storage, cleanup, and shared-service boundaries — Boundary detective

PART I

Warm-up

Reconnect with a useful idea before starting specify bounded storage, cleanup, and shared-service boundaries. 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

Handle an active reader at the expiry boundary

A lifetime policy needs a clock and a refresh rule. Duration expiry and idle expiry answer different questions. Duration counts from a defined origin; idle expiry counts from the last qualifying activity. The source does not settle every refresh or concurrency rule. State them as exercise-host policy rather than guessing WTMP methods.

Artifact A61 logically expires at 14:30. Reader R61 obtained a valid lease at 14:29. Host policy permits that lease until 14:35 but denies new leases at or after 14:30.

Use a time ledger with creation, qualifying access, active ownership and expiry decisions. Compare the exact boundary with just before and just after it. If active work can delay cleanup, distinguish logical expiry from physical deletion and record who retains responsibility. Worked case: At 14:30 A61 is expired for new use, yet R61 may finish under its existing lease until 14:35. Cleanup cannot invalidate that promised lease before its limit. Expiry and active-reader retention are separate states.

Compare the tempting alternative: Deleting bytes exactly at 14:30 would violate the existing lease; allowing new readers because one old reader remains would violate logical expiry.

Worked reasoning and supplied artifact

// Paper trace / supplied exercise-host contract; no execution claimed.
// Artifact A61 logically expires at 14:30. Reader R61 obtained a valid lease at 14:29. Host policy permits that lease until 14:35 but denies new leases at or after 14:30.
// At 14:30 A61 is expired for new use, yet R61 may finish under its existing lease until 14:35. Cleanup cannot invalidate that promised lease before its limit. Expiry and active-reader retention are separate states.

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.

Try the guided change

Reconstruct the supplied worked case first: list its inputs, intermediate decisions and final artifact. Compare each row with the explanation and identify exactly where the rejected alternative fails. Then use the changed inputs in Part IV for independent work.

• 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: Temporary asset workflow. Build a small, understandable change around specify bounded storage, cleanup, and shared-service boundaries.

Trace a new request at 14:30, existing R61 at 14:32 and cleanup after 14:35.

What to produce

A lease/expiry/cleanup matrix for three times.

• 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.

import wdb;
domain Inventory {
    const lowStock = wdb.query({
        from: products,
        select: [id, name, stock],
        where: [[ stock < 10 ]],
        order: { by: stock, direction: ascending }
    });
}

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.

• Handle an active reader at the expiry boundary
• Trace a new request at 14:30, existing R61 at 14:32 and cleanup after 14:35.
• Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Name the latest time R61 is promised access.

This marks your personal practice record only. It is not a certification or an official workspace assessment.