/* tb-ch1-branching.jsx — Chapter 1, Lesson 4: Branching and Scope. A new lesson authored entirely as data for the flow kit: no lesson-specific components. */ const CH1_BRANCH_GOALS = { state: { id: 'state', n: 'A', label: 'Store the facts', gloss: 'A bool holds the simplest possible piece of state: one fact that is either true or false.', }, branch: { id: 'branch', n: 'B', label: 'Let the fact choose a path', gloss: 'The same program can behave differently, because a bool decides which lines run.', }, }; const CH1_BRANCH_SUBGOALS = { flag: { id: 'flag', n: 'A.a', label: 'Store the deciding fact', gloss: 'Create the bool the branch will read.', goal: 'state' }, amount: { id: 'amount', n: 'A.b', label: 'Store the value that may change', gloss: 'The branch can only change a value that already exists.', goal: 'state' }, test: { id: 'test', n: 'B.a', label: 'Test the condition', gloss: 'Read the bool and choose whether the guarded lines run.', goal: 'branch' }, guarded: { id: 'guarded', n: 'B.b', label: 'Run the guarded line', gloss: 'These lines run only on the true path.', goal: 'branch' }, report: { id: 'report', n: 'B.c', label: 'Report the result', gloss: 'Show what the chosen path left in memory.', goal: 'branch' }, }; const CH1_BRANCH_CODE = { layout: 'frame', goals: CH1_BRANCH_GOALS, subgoals: CH1_BRANCH_SUBGOALS, frame: [ { kind: 'seg', subgoal: 'flag' }, { kind: 'seg', subgoal: 'amount' }, { kind: 'wrap', subgoal: 'test', header: 'br-line-3', footer: 'br-line-close', hint: 'owns the guarded line', body: [{ kind: 'seg', subgoal: 'guarded' }], }, { kind: 'seg', subgoal: 'report' }, ], lines: [ { id: 'br-line-1', num: '1', indent: 0, text: 'bool isMember = true;', subgoal: 'flag', translation: 'Store one fact: this customer is a member.' }, { id: 'br-line-2', num: '2', indent: 0, text: 'double total = 40.0;', subgoal: 'amount', translation: 'Store the order total the branch may change.' }, { id: 'br-line-3', num: '3', indent: 0, text: 'if (isMember) {', subgoal: 'test', badge: 'condition', badgeBg: '#fef3c7', badgeBorder: '#fcd34d', badgeColor: '#92400e', translation: 'Read isMember. Run the lines inside the block only when it holds true.', }, { id: 'br-line-3-body', num: '4', indent: 1, text: 'total = total - 5.0;', subgoal: 'guarded', badge: 'true path', badgeBg: '#dcfce7', badgeBorder: '#86efac', badgeColor: '#166534', translation: 'Take five off the total. This line exists only on the true path.', }, { id: 'br-line-close', num: '5', indent: 0, text: '}', translation: 'Close the guarded block. Execution continues here either way.' }, { id: 'br-line-6', num: '6', indent: 0, text: 'Console.WriteLine(total);', subgoal: 'report', translation: 'Print the total the chosen path left behind.' }, ], tokens: { bool: { tone: 'type', description: 'A type with exactly two values: true and false.' }, double: { tone: 'type', description: 'A number that can hold a fractional part.' }, isMember: { tone: 'name', description: 'The stored fact the branch reads.' }, total: { tone: 'name', description: 'The value the branch may change.' }, if: { tone: 'op', description: 'Choose whether the block below runs.' }, true: { tone: 'value', description: 'One of the two boolean values.' }, '40.0': { tone: 'value', description: 'The order total before any discount.' }, '5.0': { tone: 'value', description: 'The member discount.' }, 'Console.WriteLine': { tone: 'call', description: 'Evaluate the argument and display it in the console.' }, }, }; const CH1_BRANCH_TRANSFER_CODE = { lines: [ { id: 'tr-1', num: '1', text: 'bool isLate = false;' }, { id: 'tr-2', num: '2', text: 'double fee = 0.0;' }, { id: 'tr-3', num: '3', text: 'if (isLate) {' }, { id: 'tr-3-body', num: '4', text: ' fee = fee + 2.5;' }, { id: 'tr-close', num: '5', text: '}' }, { id: 'tr-6', num: '6', text: 'Console.WriteLine(fee);' }, ], }; const CH1_BRANCH_STATES = [ { label: 'Before execution', desc: 'Nothing is stored yet, so there is no fact for the branch to read.', memory: [], console: [] }, { label: 'After line 1', desc: 'isMember holds the one fact this program branches on.', memory: [{ name: 'isMember', type: 'bool', value: 'true' }], console: [] }, { label: 'After line 2', desc: 'Both variables exist. The total is still the undiscounted amount.', memory: [{ name: 'isMember', type: 'bool', value: 'true' }, { name: 'total', type: 'double', value: '40.0' }], console: [], }, { label: 'After line 4', desc: 'The condition was true, so the guarded line ran and changed the total.', memory: [{ name: 'isMember', type: 'bool', value: 'true' }, { name: 'total', type: 'double', value: '35.0' }], console: [], }, { label: 'After line 6', desc: 'Execution continues past the block and prints whatever the chosen path left in total.', memory: [{ name: 'isMember', type: 'bool', value: 'true' }, { name: 'total', type: 'double', value: '35.0' }], console: ['35'], }, ]; const CH1_BRANCHING_LESSON = { id: 'ch1-branching-scope', chapterId: 'ch1', source: 'ch1/ch1-3.md', stableUrl: 'ch1/branching-and-scope', order: 4, title: 'Branching And Scope', kicker: 'Chapter 1', learningTarget: 'Use a stored bool to choose which lines run, and read the resulting state.', roadmap: { order: 4, sourceAnchors: ['ch1/ch1-3.md'], reviewConcepts: ['boolean data', 'assignment', 'console output'] }, availableSyntax: [ { group: 'Boolean data', items: [ { term: 'bool name = true;', note: 'Store one fact that is either true or false.', source: 'ch1-1' }, { term: 'true / false', note: 'The only two boolean values.', source: 'ch1-1' }, ], }, { group: 'Branching', items: [ { term: 'if (condition) { ... }', note: 'Run the block only when the condition holds.', source: 'ch1-3' }, { term: '{ ... }', note: 'A block groups the lines a branch guards.', source: 'ch1-3' }, ], }, ], chapterNav: { chapters: window.FUNCS_CHAPTERS || [] }, chapterExamples: (window.CH1_CHAPTER_EXAMPLES || []).map(item => ({ ...item, current: item.title === 'Branching and Scope' })), fullExample: { header: { chapterLabel: 'Chapter 1', exampleTitle: 'Example: Branching And Scope', modeLabel: 'Full walkthrough', instructions: 'Run the program line by line. Watch the condition decide whether the guarded line ever runs.', programLabel: 'Program.cs', programNote: 'The condition and the line it guards are labeled outside the code.', }, code: CH1_BRANCH_CODE, subgoals: CH1_BRANCH_SUBGOALS, states: CH1_BRANCH_STATES, }, preQuiz: { title: 'Pre-Quiz', prompt: 'Commit to what the branch does before the walkthrough explains it.', }, mainLesson: { title: 'Branching And Scope', label: 'Main Lesson', intro: 'A bool is the smallest piece of state a program can hold: one fact, true or false. That is enough to stop a program from running the same way every time.', acts: [ { n: 1, title: 'One Fact, Stored', body: [ 'Every program so far ran straight through: line 1, then 2, then 3, in that order, every time.', 'A bool records a single fact — member or not, late or not — and that fact is what a branch will read.', ], code: ['bool isMember = true;'], translations: ['Store one fact the rest of the program can ask about.'], }, { n: 2, title: 'The Condition Picks A Path', body: [ 'An if statement reads the bool and chooses. When it holds true the guarded lines run; when it holds false they are skipped entirely.', 'The straight line 1 → 2 → 3 → 4 becomes a fork, and only one path is ever taken.', ], code: ['if (isMember) {', ' total = total - 5.0;', '}'], translations: ['Take five off the total only when isMember is true.'], }, { n: 3, title: 'After The Block, One State', body: [ 'Both paths rejoin at the line after the closing brace, so the rest of the program is written once.', 'What differs is the state left behind: the printed total is the evidence of which path ran.', ], code: ['Console.WriteLine(total);'], translations: ['Print 35 on the true path, 40 on the false one.'], }, ], }, rigorousQuiz: { title: 'Rigorous Quiz', prompt: 'Trace a nearby branch whose condition is false, and say what that leaves in memory.', transferCode: CH1_BRANCH_TRANSFER_CODE, }, exercises: { title: 'Branching Practice Set', label: 'Exercises', intro: 'Five problems on choosing a path with a stored bool. Work them away from this page.', }, flow: { goal: { intent: 'Same walkthrough shell as ch2.4, rendered from this lesson\'s data. The footer reads Continue while nothing has run, then becomes Run next line once execution starts.', badge: 'Full walkthrough', activeGoal: 'state', activeSubgoal: 'flag', activeKey: 'br-line-1', startLabel: 'Continue — start running', startStatus: 'goal · nothing has run', runLabel: 'Run next line', note: 'the branch has not been tested yet — the guarded line may never run at all', }, preQuiz: { intent: 'Part 1 asks for the shape of a branching program: which categories run, in what order. Part 2 opens each one for a single detail question.', kicker: 'Pre-Quiz · Branching And Scope', part1Prompt: 'Put the five categories in the order they run for this program. Guessing is fine — the walkthrough revisits every one.', part2Prompt: 'The order is set. Open each category and answer its one question.', orderSuccess: 'That is the shape: store the facts, test one of them, run the guarded line only if the test held, then report what is left.', orderRetry: 'Red rows carry the reason they belong elsewhere. Fix your picture of the order, then move to the details.', categories: [ { id: 'flag', n: 'A.a', label: 'Store the deciding fact', why: 'Nothing can be tested before the fact exists.' }, { id: 'amount', n: 'A.b', label: 'Store the value that may change', why: 'The guarded line changes a value that must already exist.' }, { id: 'test', n: 'B.a', label: 'Test the condition', why: 'The condition is read before any guarded line can run.' }, { id: 'guarded', n: 'B.b', label: 'Run the guarded line', why: 'This runs only after the condition is found true.' }, { id: 'report', n: 'B.c', label: 'Report the result', why: 'Printing happens after the branch has finished.' }, ], shuffled: ['test', 'report', 'amount', 'guarded', 'flag'], details: { flag: { type: 'pick line', kind: 'choice', mono: true, q: 'Which line stores the fact the branch reads?', choices: ['bool isMember = true;', 'double total = 40.0;', 'if (isMember) {'], correct: 0, why: 'A bool holds one fact. That is the value the condition will ask about.', }, amount: { type: 'fill the value', kind: 'chips', q: 'What does total hold when the condition is tested?', chips: ['40.0', '35.0', '5.0', 'true'], correct: '40.0', why: 'Line 2 stored 40.0 and nothing has changed it yet — the guarded line has not run.', }, test: { type: 'multiple choice', kind: 'choice', q: 'What does if (isMember) actually check?', choices: ['Whether the value stored in isMember is true', 'Whether isMember was declared as a bool', 'Whether total is greater than zero'], correct: 0, why: 'The condition reads the stored value. Nothing about the declaration or the total is involved.', }, guarded: { type: 'fill the value', kind: 'chips', q: 'How many times does line 4 run in this program?', chips: ['0', '1', '2'], correct: '1', why: 'isMember is true, so the guarded line runs exactly once. A branch is not a loop.', }, report: { type: 'predict output', kind: 'chips', q: 'What does the program print?', chips: ['35', '40', '5', 'true'], correct: '35', why: 'The true path took five off 40.0, so the line after the block prints 35.', }, }, }, mainLesson: { intent: 'One page, one scroll, with the same gate as ch2.4: the reading below the current check stays visible but blurred, so nothing gets skipped.', completeNote: 'Every check was answered, so the whole page is now readable end to end for review.', checks: [ { type: 'multiple choice', kind: 'choice', mono: true, q: 'Which line stores a fact rather than a number?', choices: ['bool isMember = true;', 'double total = 40.0;', 'Console.WriteLine(total);'], correct: 0, why: 'bool holds one of two values. That is the whole of what it can say.', }, { type: 'fill the value', kind: 'chips', q: 'isMember is true, so after line 4 total holds ?', chips: ['35.0', '40.0', '5.0', '45.0'], correct: '35.0', why: 'The guarded line ran once and took 5.0 off the stored 40.0.', }, { type: 'multiple choice', kind: 'choice', q: 'If isMember held false instead, what would the program print?', choices: ['40 — the guarded line is skipped entirely', '35 — the discount happens anyway', 'Nothing — the program stops at the condition'], correct: 0, why: 'A false condition skips the block and continues at the line after it, with total untouched.', }, ], }, rigorousQuiz: { intent: 'Five questions, one in view at a time, each scoped to one moment of a branch whose condition is false — the case learners get wrong most often.', codeLabel: 'Transfer program', success: 'Full marks: you traced a branch that never ran and still said exactly what it left behind.', cards: [ { id: 'order', type: 'order the lines', kind: 'order', q: 'Order the lines that actually run, first to last. One of these never runs.', bank: ['Console.WriteLine(fee);', 'fee = fee + 2.5;', 'bool isLate = false;', 'if (isLate) {', 'double fee = 0.0;'], correct: ['bool isLate = false;', 'double fee = 0.0;', 'if (isLate) {', 'Console.WriteLine(fee);'], placeholder: 'tap a line below', why: 'The condition is false, so the guarded line is skipped and never belongs in the run order.', }, { id: 'guard', type: 'pick the line', kind: 'choice', mono: true, q: 'Which line decides whether fee ever changes?', choices: ['bool isLate = false;', 'if (isLate) {', 'fee = fee + 2.5;'], correct: 1, why: 'The condition is the decision. The line above only stores the fact it reads.', }, { id: 'row', type: 'fill the trace row', kind: 'row', q: 'Fill the row for the moment the condition is tested.', rowLabel: 'if (isLate)', columns: ['at line', 'isLate', 'fee'], cells: [ { col: 'isLate', chips: ['true', 'false'], correct: 'false' }, { col: 'fee', chips: ['0.0', '2.5', 'nothing yet'], correct: '0.0' }, ], why: 'isLate was stored as false on line 1, and fee still holds the 0.0 from line 2.', }, { id: 'output', type: 'predict the value', kind: 'chips', q: 'What does the program print?', chips: ['0', '2.5', 'false', '(no output)'], correct: '0', why: 'The guarded line never ran, so fee is still 0.0 and prints as 0.', }, { id: 'why', type: 'explain why', kind: 'choice', q: 'Why does fee keep its starting value?', choices: ['The condition was false, so the guarded line was skipped', 'Adding 2.5 to 0.0 leaves 0.0', 'A double cannot be changed after it is stored'], correct: 0, why: 'Skipping is the mechanism. The addition never happened at all.', }, ], }, exercises: { intent: 'Stated problems, worked away from the page: what to produce, one worked example, and the constraints an answer must satisfy.', intro: 'Five problems on choosing a path with a stored bool. Nothing is solved inline.', problems: [ { n: 1, title: 'Name the parts', tag: 'warm-up', statement: 'For the program below, identify the line that stores the deciding fact, the line that tests it, and every line the test guards.', given: ['bool isMember = true;', 'double total = 40.0;', 'if (isMember) {', ' total = total - 5.0;', '}', 'Console.WriteLine(total);'], constraints: ['Quote each line exactly.', 'State which lines are skipped when the condition is false.', 'Say in one sentence where the two paths rejoin.'], }, { n: 2, title: 'Trace both paths', tag: 'core', statement: 'Trace the same program twice by hand: once with isMember true, once with isMember false. Write the value of total after every line that runs.', example: { inLabel: 'input', in: 'isMember = false', out: '40' }, constraints: ['Show the two traces side by side.', 'Skip the guarded line in the false trace rather than crossing it out.', 'End each trace with the printed value.'], }, { n: 3, title: 'Add the other path', tag: 'core', statement: 'Rewrite the program so a non-member is charged a 2.0 surcharge instead of receiving the discount. Members must still get five off.', example: { inLabel: 'input', in: 'isMember = false', out: '42' }, constraints: ['Exactly one condition.', 'Each path changes total exactly once.', 'The printing line appears only once in your program.'], }, { n: 4, title: 'Repair the block', tag: 'core', statement: 'The program below always applies the discount, member or not. State what the author meant, explain what the code actually does, and fix it.', given: ['bool isMember = false;', 'double total = 40.0;', 'if (isMember)', ' Console.WriteLine("member");', ' total = total - 5.0;', 'Console.WriteLine(total);'], example: { inLabel: 'input', in: 'isMember = false', out: '40' }, constraints: ['Explain the failure in terms of what the condition guards, not indentation.', 'Make the smallest change that fixes it.', 'State the printed value before and after your fix.'], }, { n: 5, title: 'Condition from a computation', tag: 'stretch', statement: 'A program stores an order total. Write the lines that give free shipping when the total is above 100.0, and print the shipping cost either way.', example: { inLabel: 'input', in: 'total = 120.0', out: '0' }, constraints: ['Store the condition as a named bool before testing it.', 'Justify in one sentence why naming the bool is clearer than testing inline.', 'State what your program prints for a total of exactly 100.0.'], }, ], }, }, }; Object.assign(window, { CH1_BRANCH_GOALS, CH1_BRANCH_SUBGOALS, CH1_BRANCH_CODE, CH1_BRANCH_STATES, CH1_BRANCHING_LESSON });