Types after names — Flash-check repair · Casilian Modding School

PART I

Warm-up

Reconnect with a useful idea before starting types after names. 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.

Recall note

A rough note is enough. You can revise it after the example.

PART II

Instruction & guided example

Diagnose a wrong return kind before arithmetic

A helper can contain a valid-looking expression that does not match its promised result kind. Start by asking what kind of value the expression produces. This diagnosis differs from a wrong operator that still produces the right kind but the wrong numeric value.

The broken hasStock declaration promises bool but returns stock + 1, an integer expression. At stock 3, arithmetic predicts 4, which still does not answer “is stock positive?” Repair the expression to stock > 0, which yields true. Changing the promise to i32 would describe a different helper rather than satisfy the stated question.

Do not claim a precise compiler diagnostic was observed here. The source-level mismatch is enough to explain the repair. Also do not treat a positive integer as implicit true; that conversion has not been established by the exercise.

Worked reasoning and supplied artifact

// Broken: the return expression does not answer the Boolean question.
fnc hasStock(stock: i32) -> bool {
    return stock + 1;
}

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

// Broken: the return expression does not answer the Boolean question.
This comment explains intent for a reader. It is not an operation and should not be counted as an executed result.
fnc hasStock(stock: i32) -> bool {
Read the function name, its parameter names/types and the result type after ->. This is the contract the body must satisfy.
return stock + 1;
Evaluate the following expression using the current values, then send its result to the caller. Explain the value; do not confuse it with printed output.
}
Close the nested block or value begun earlier. Match it to its opening boundary to keep the structure readable.

Try the guided change

Mark the promised type, classify the existing expression, then replace it with the comparison and trace stock 3 and 0.

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.

Prediction or guided notes

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.

Your drafts remain here. Continue whenever you are ready.

PART IV

Independent practice

Project context: Workshop stock counter. Build a small, understandable change around types after names.

Repair a bool-returning hasRoom helper whose body returns capacity - used. Use an explicit comparison and provide available/full cases. Explain why simply renaming it remaining would change its contract.

What to produce

A narrow Boolean-expression repair, two typed traces and a distinction between repair and requirement change.

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.

Your .ws practice draft

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?

Original learning-path task and reference

In a media review console, demonstrate types after names. 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.

fnc total() -> i32 {
    vary count: i32 = 1;
    const bonus: i32 = 2;
    count += bonus;
    return count;
}

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.

Which diagnosis applies to stock + 1 under -> bool?Its integer result kind does not match the promised Boolean questionIt is necessarily an ownership escapeThe function name automatically converts 4 to true

Explain a normal or boundary case

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.

Diagnose a wrong return kind before arithmetic
A helper can contain a valid-looking expression that does not match its promised result kind. Start by asking what kind of value the expression produces. This diagnosis differs from a wrong operator that still produces the right kind but the wrong numeric value.
Separate source-backed behavior, host requirements and untested predictions.

One small recap task

Give an example of a wrong numeric formula that still returns the declared i32 kind.

Your recap

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