Understanding Follow Function

Duration: 7 min

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Module outline

  1. About the Course: About the Course
  2. Section 1 | Language (Hindi): भाषा, लिपि, ध्वनि, वर्ण, अक्षर, स्वर, व्यंजन, मात्रा और संयुक्ताक्षर, वर्तनी, वर्ण-विन्यास, अनुस्वार, अनुनासिक, चंद्रबिंदु और ‘र’ के रूप, शब्द, पद और शब्द-भेद, संज्ञा और सर्वनाम, विशेषण और क्रिया, लिंग, वचन, पुरुष और कारक, काल, वाच्य, वाक्य और वाक्य-भेद, संधि, समास, विलोम शब्द, पर्यायवाची शब्द, सामान्य अशुद्धियाँ, अनेक शब्दों के लिए एक शब्द, मुहावरे और लोकोक्तियाँ, अपठित गद्यांश और अपठित पद्यांश, Multi-Topic Content (Cross-Concept Material), वर्णमाला
  3. Section 1 | Language (उर्दू भाषा — 22 प्रश्न (निश्चित)): Spelling & Diacritics, Grammar (اسم, فعل, صفت, ضمیر), Vocabulary, Idioms & Proverbs, Comprehension
  4. Section 1 | Language (বাংলা / बांग्ला भाषा — 22 प्रश्न (निश्चित)): Bangla Script and Sounds, Bangla Grammar and Usage, Bangla Word Formation and Vocabulary, Reading and Text Interpretation
  5. Section 1 | Language (English): Vocabulary, Noun, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Tenses, Pronoun, Verb, Adverb, Preposition, Articles, Determiner, Conjunction, Modals, Active Passive Voice (Voice), Direct and Indirect Speech, Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Construction, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Verbal Analogy (Word Based Analogy), Facts, Inference and Judgements
  6. Section 2 | Primary Maths & Reasoning: Ratio and Proportion (Ratios), Divisibility Rules, Mixture and Alligation, Permutation and Combination, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Percentage, Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Mensuration and Geometry, Age Problems, Arithmetic, Powers and Exponents (Surds and Indices), Algebra, Probability, Trigonometry, Syllogisms, Seating Arrangements, Blood Relations, Directions (Direction Test), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence
  7. Section 2 | General Awareness (GK + Current Affairs): Polity, Physics, Biology, State Wise GK, Chemistry, History, Geography, Indian Economy, Environment, GK- Current Affairs, Static General Knowledge
  8. Section 3 | Computer System and Org. (CSO): Basics of COA, Floating Point Rep, Cache Memory Organization, Instr Formats & Modes, Programming the Basic Computer, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design
  9. Section 3 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control
  10. Section 3 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Process Synchronization
  11. Section 3 | Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics
  12. Section 3 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Minimum Spanning Trees, Shortest Path Algos
  13. Section 3 | Theory Of Computation & Compiler Design: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization
  14. Section 3 | Emerging Trends (AI, Societal Ethics & MS Office): Artificial Intelligence, Emerging Tech Trends, Society, Law & Ethics, MS Office Applications
  15. Section 3 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Maintenance and Configuration Management, Software Testing
  16. Section 3 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  17. Section 3 | OOPS, C++, JAVA, HTML: OOPS with C++, Java, HTML Basics, CSS
  18. Section 3 | Java: Java Fundamentals, Array, String, IO & References
  19. Section 3 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  20. Section 3 | Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  21. Section 3 | Multimedia: Multimedia
  22. BPSC Previous Year Papers:
  23. BPSC Full Mock Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a detailed lecture on computing Follow sets within the context of Context-Free Grammars and compiler design. The instructor begins by defining Follow(A) as the set of terminals that can appear immediately to the right of a non-terminal A in any sentential form. He systematically presents four fundamental rules used to calculate these sets, covering cases for start symbols, productions with non-epsilon suffixes, and productions where the suffix can derive epsilon. The lecture then transitions into practical applications, solving examples of increasing complexity to demonstrate the application of these rules.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lecture begins with the definition of Follow(A) displayed on the slide. The instructor explains that Follow(A) contains terminals following A in sentential grammars. He lists four specific rules: Rule 1 states that if A is the start symbol, Follow(A) includes the end marker $. Rule 2 applies when A is followed by a non-epsilon beta, setting Follow(A) to First(beta). Rule 3 handles the case where A is the last symbol in a production, equating Follow(A) to Follow(S). Rule 4 addresses the scenario where A is followed by a beta that can derive epsilon, combining First(beta) and Follow(S). The instructor uses hand-drawn diagrams with arrows and lines to visually represent derivations and the position of terminals relative to non-terminals.

  2. 2:00 – 5:00 02:00-05:00

    Next, the presenter moves to a simple example where S -> epsilon. He determines First(S) is {epsilon} and Follow(S) is {$} because S is the start symbol. He then introduces a slightly more complex grammar: S -> aA and A -> bA / epsilon. He calculates First(S) as {a} and First(A) as {b, epsilon}. For Follow sets, he establishes Follow(S) as {$}. To find Follow(A), he notes that A appears at the end of the production S -> aA. Applying Rule 3, he concludes that Follow(A) must equal Follow(S), which is {$}. He writes these values clearly on the slide to reinforce the concept.

  3. 5:00 – 7:06 05:00-07:06

    Subsequently, the class analyzes a grammar with multiple productions: S -> AaBb / BbAa, with A -> epsilon and B -> epsilon. The instructor calculates Follow(S) as {$}. For Follow(A), he observes that A is followed by 'a' in both productions, so Follow(A) = {a}. Similarly, B is followed by 'b' in both productions, so Follow(B) = {b}. Finally, he introduces a standard arithmetic expression grammar: E -> E+T / T, T -> T*F / F, F -> (E) / id. He begins calculating Follow sets for this recursive grammar. He determines Follow(E) = {$, +} based on the start symbol and the '+' in E -> E+T. He finds Follow(T) = {*, $, +} by combining the end marker, the '*' from T -> T*F, and the '+' from E -> E+T. He writes Follow(F) = {*, $, +}, indicating the terminals that can follow F in the derived strings.

The video effectively bridges theoretical definitions with practical calculation methods. By starting with abstract rules and moving to concrete examples, the instructor demonstrates how to handle epsilon productions and recursive structures. The progression from simple start symbol cases to complex arithmetic grammars provides a comprehensive guide for students learning to construct parsing tables or analyze grammars.

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