Names, parameters, and return types — Change one requirement

PART I

Warm-up

Reconnect with a useful idea before starting names, parameters, and return types. 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

Add one input when the rule needs one input

A changed requirement sometimes needs a new parameter rather than a hardcoded constant. If each order has a different fee, the helper should receive that fee. This makes the caller’s responsibility explicit and avoids editing a reusable definition for every order.

The original subtotal(quantity,unitPrice) returns quantity * unitPrice. Revised total(quantity,unitPrice,fee) returns quantity * unitPrice + fee. For (3,90,20), the subtotal is 270 and total 290. For the same items with fee 0, total is 270. The new parameter varies the fee without changing the formula.

After adding a required parameter, update every shown call. A call with only two arguments no longer describes the complete revised contract. Do not invent an optional-parameter or default-value syntax whose behavior is not supplied here.

Worked reasoning and supplied artifact

fnc total(quantity: i32, unitPrice: i32, fee: i32) -> i32 {
    return quantity * unitPrice + fee;
}
fnc main() -> i32 {
    return total(3, 90, 20);
}

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

fnc total(quantity: i32, unitPrice: i32, fee: i32) -> i32 {
Read the function name, its parameter names/types and the result type after ->. This is the contract the body must satisfy.
return quantity * unitPrice + fee;
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.
fnc main() -> i32 {
Read the function name, its parameter names/types and the result type after ->. This is the contract the body must satisfy.
return total(3, 90, 20);
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

Trace the 20-cent fee and zero-fee calls, then identify which part of the source changed compared with a two-parameter subtotal.

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: Snack-shop calculator. Build a small, understandable change around names, parameters, and return types.

Extend a helper for base reward plus bonus to include a caller-supplied multiplier on the bonus. Update two caller examples and explain their argument order.

What to produce

A three-parameter helper, two updated calls and traces such as (10,3,2) → 16 and (10,3,0) → 10.

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 classroom scheduling assistant, demonstrate names, parameters, and return types. Adapt the task to a second host-neutral application context without changing the imported API contract. Include .ws source and a host-resource contract; compare at least one normal case and one edge case.

fnc add(a: i32, b: i32) -> i32 {
    return a + b;
}
fnc main() -> i32 {
    return add(2, 3);
}

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.

What must a caller supply after the new required fee parameter is introduced?The fee argument in the declared positionOnly a comment saying a fee existsAn invented default keyword

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.

Add one input when the rule needs one input
A changed requirement sometimes needs a new parameter rather than a hardcoded constant. If each order has a different fee, the helper should receive that fee. This makes the caller’s responsibility explicit and avoids editing a reusable definition for every order.
Separate source-backed behavior, host requirements and untested predictions.

One small recap task

State one tradeoff between a hardcoded fee and a fee parameter.

Your recap

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