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Context-free languages: BNF and syntax diagrams

AQA 75174.4 L4A-levelLesson packSubscription
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This worksheet marks itself

Set it as homework or classwork and every answer is marked as pupils go, with feedback on what they got wrong. The scores go straight into your mark book, so you can see who needs help before the next lesson.

  • 12 questions
  • 31 marks
  • about 40 minutes
  • marked instantly

Question types: short answer, multiple choice, matching, true or false.

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Try one from this worksheet

The syntax diagram shown defines a <number>. Identify the string that is a valid <number>.

Pick an answer: it's marked straight away, just as your pupils would see it.

About this resource

AQA A-level Computer Science (7517) 4.4.3.1 Backus-Naur Form (BNF) / syntax diagrams. C# lesson 4 of 6 in 4.4 Theory of computation: a trace-the-recursion Do Now, a short key idea, an 11-challenge ladder in three sets with exact test data, two exam questions and a worksheet. Replaces aqa-7517-4-4…

18 slides.

Lesson outline

  1. Do Now: trace the recursion
  2. Do Now: answers
  3. Key idea: BNF: production rules
  4. Key idea: Syntax diagrams: the same rules, drawn
  5. Quick check: valid or not?
  6. Key idea: In C#: one method per rule
  7. Key idea: What BNF can do that a regular expression cannot
  8. Set 1: one method per rule
  9. Set 2: split the string
  10. Exam question E1: check the syntax
  11. Model answer E1
  12. Exam question E2: write the rule, then explain
Unit bundle4.4 Theory of computation · full lessons
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