<cascade>

<cascade> reveals its children one at a time as the learner makes progress. Each child is hidden until the preceding child has been completed — answered correctly (creditAchieved = 1), or having no creditAchieved at all (in which case it is treated as auto-completed the moment it becomes visible).

The numCompleted property tracks how many children have been completed so far. Use <cascadeMessage> inside a <cascade> to show a “continuation message” in place of a not-yet-revealed entry.

To give a cascade a title, a box or a score, put it inside a <section>, as in the examples below. The section is scored on the steps inside the cascade, the same as if they were written in the section directly.

A <cascade> automatically turns on aggregateScores on every scored child (sections, <problem>, nested <cascade>s, even bare <p> paragraphs that contain answers). That is what gives each child a creditAchieved value the cascade can watch — without it, a paragraph or section containing an <answer> would not roll the answer’s credit up into its own, and the cascade would have no way to tell when the child is “done”. You therefore do not need to set aggregateScores by hand on cascade children.

A handGraded <answer> is the one exception to “answered correctly”. Its credit stays at 0 until an instructor grades it, which happens long after the learner has moved on, so a cascade would otherwise stop there for good. Instead, such an answer counts as completed as soon as the learner submits a response that is not blank — submitting an untouched input does not count, except for a <booleanInput>, whose unchecked box is itself an answer. The answer’s actual creditAchieved is unchanged; it is still awaiting a grade.

The same rule colors the heading bar of a boxed or collapsible section, so a step whose questions have all been answered shows as completed rather than staying gray until an instructor gets to it. Set completedColorRequiresCredit on a section, on any section that encloses it, or on the cascade itself, to have the bar wait for the real credit instead; that affects only the color, never when the cascade advances. The cascade’s completedColor, inProgressColor and notStartedColor set the colors of its steps’ heading bars; when it sets none, its steps use the colors of the section around it.

The sections in a cascade are numbered along with the sections beside it, just as if they were written there directly, and the sections after the cascade continue the count. Inside a <problems>, the problems in a cascade are likewise numbered as items of the list. Revealing a step never changes a number.

Attributes and Properties

Examples

Example: Step-by-step questions

Each <section> is revealed only after the previous one is answered correctly. The numCompleted property of the named <cascade> updates as the learner progresses. The title comes from the enclosing <section>, and the three steps are subsections of it.

Example: Nested cascade inside a section

The outer <cascade> reveals its three <section> children one at a time. The middle section contains an inner <cascade> whose children are bare <p> paragraphs. Because the outer cascade has turned on aggregateScores for the middle section, and that section’s inner cascade turns it on for each <p>, each paragraph rolls up the credit of its <answer> — so the inner cascade can hide the second paragraph until the first answer is correct, then reveal it.

Example: Cascade with continuation messages

A <cascadeMessage> replaces the entry that would otherwise be hidden. One shows at a time — the first one after the last revealed section — so here “Solve the previous step to continue” shows until Step 1 is completed, at which point Step 2 appears and “One more step to go” takes its place.

Example: A scored, boxed cascade

The enclosing <section> supplies the box and the score. Its credit comes from the answers inside the cascade, the same as if they were written in the section directly.

Attribute Examples

Attribute Example: hideFutureSections

With hideFutureSections, later children are completely hidden (titles and all) until the preceding child is completed. Without it, the title of the next section still appears greyed-out so the learner can see what is coming.

Attribute Example: revealAll

Setting revealAll shows every child immediately, ignoring completion. This is useful when authoring (so you can see every step) or when you want the cascade structure without enforcing the order.

Attribute Example: boxAll

boxAll draws a box around every child section, as if each had been given boxed. To box the whole cascade instead, put it in a boxed section.

Property Examples

Property Example: numCompleted

The numCompleted property counts how many children have been completed so far, in order. Once a child is skipped (e.g. its answer is wrong), counting stops at that point.