PART I
Warm-up
Reconnect with a useful idea before starting reading a function from left to right. 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
Give a helper one clear responsibility
A small helper is easiest to audit when its name and body describe one operation. A duration helper should calculate duration; a mounting operation belongs to a host boundary. This makes the arithmetic useful even when no UI service is available.
remaining(total,used) returns total - used. For total 30 minutes and used 12 minutes, substitute to obtain 30 - 12 = 18 minutes. The helper neither starts a timer nor schedules an event. Its useful slice is a returned duration that a future host integration may display.
Calling the helper startTimer would imply a side effect absent from the code. Likewise, adding an invented timer API to make the example feel complete would hide the lesson’s simple contract. Keep honest names and add host integration only when its real contract is supplied.
Worked reasoning and supplied artifact
fnc remaining(total: i32, used: i32) -> i32 {
return total - used;
}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 remaining(total: i32, used: i32) -> i32 {Read the function name, its parameter names/types and the result type after ->. This is the contract the body must satisfy.
return total - used;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 remaining(30,12) and rename the parameter used to elapsed in both signature and body without changing the calculation.
- 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: Snack-shop calculator. Build a small, understandable change around reading a function from left to right.
Create a helper for remaining crafting slots from capacity and occupied slots. Choose descriptive names, supply normal and full-capacity cases, and state what it does if occupied exceeds capacity under the arithmetic alone.
What to produce
One subtraction helper, cases (8,3) → 5 and (8,8) → 0, plus an over-capacity policy question.
- 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?
remaining(total,used) returns total - used. For total 30 minutes and used 12 minutes, substitute to obtain 30 - 12 = 18 minutes. The helper neither starts a timer nor schedules an event. Its useful slice is a returned duration that a future host integration may display.
Calling the helper startTimer would imply a side effect absent from the code. Likewise, adding an invented timer API to make the example feel complete would hide the lesson’s simple contract. Keep honest names and add host integration only when its real contract is supplied.
Original learning-path task and reference
In a rhythm-game audio editor, demonstrate reading a function from left to right. Create the smallest .ws integration that demonstrates the section 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.
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.
- Give a helper one clear responsibility
- A small helper is easiest to audit when its name and body describe one operation. A duration helper should calculate duration; a mounting operation belongs to a host boundary. This makes the arithmetic useful even when no UI service is available.
- Separate source-backed behavior, host requirements and untested predictions.
One small recap task
Choose a function name that accurately describes capacity minus occupied.
This marks your personal practice record only. It is not a certification or an official workspace assessment.