LALR(1) Part-3

Duration: 8 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. General Aptitude & Reasoning: Number System, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Speed Time and Distance, Mixture and Alligation, Data Interpretation, Algebra, Probability, Permutation and Combination, Venn Diagram, HCF LCM, Divisibility Rules, Age Problems, Pipe and Cistern, Partnership, Linear Algebra, Sequence and Series (Series), Statistics, Powers and Exponents (Surds and Indices), Arithmetic, Mensuration and Geometry, Calculus, Trigonometry, Vectors, Speed Mathematics and Basic Mathematics, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analogy, Series (Number and Letter Series) (Numerical Relations and Reasoning), Puzzle Solving (Puzzles), Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Calendar, Seating Arrangements, Coding Decoding, Blood Relations, Directions (Direction Test), Clock, Analytical Reasoning (Counting Figures Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Inequality, Data Sufficiency, Cubes & Dices
  3. Computer Networks & Cybersecurity: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware Basics, Network Security
  4. Programming, Data Structures & Algorithms: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  5. AI, Machine Learning, Big Data & Cloud: Emerging Tech Trends, Artificial Intelligence, Big Data Systems, Approaches to AI, Search Algorithms, Knowledge Representation, Cloud Computing
  6. Digital Logic & Computer Organization: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. TOC & Compiler: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  8. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
  9. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Distributed Systems
  10. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Object Oriented Technology, HTML Basics, JavaScript-Basics, Java, XML
  11. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Data Warehousing & Mining, Enhanced Data Models, NoSQL
  12. Other Recurring CS Topics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, Multimedia
  13. Live Classes: ISRO Live classes
  14. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video presents a comprehensive lecture on constructing an SLR(1) parsing table for a specific context-free grammar. The instructor begins by defining the grammar rules, which include productions for S, A, and B. He then introduces the concept of grammar augmentation by adding a new start symbol S' and the production S' -> S. The core of the lecture involves building the canonical collection of LR(0) items, which forms the states of the DFA used in parsing. The instructor systematically derives each state (I0 through I12) by computing closures and transitions. Finally, he constructs the parsing table, mapping states to actions (shift, reduce, accept) and goto transitions based on the derived items and lookahead symbols. This process is crucial for compiler design and understanding how parsers work.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the grammar with productions S -> Aa, S -> bAc, S -> Bc, S -> bBa, A -> d, and B -> d. He explains the need for grammar augmentation to handle the start symbol correctly, adding S' -> S. He then begins constructing the initial state I0. He writes down the closure of the augmented production S' -> .S, $, which includes S -> .Aa, $, S -> .bAc, $, S -> .Bc, $, and S -> .bBa, $. He further expands the closure by adding productions for non-terminals A and B that appear after the dot, resulting in A -> .d, a and B -> .d, c. This state I0 serves as the starting point for the state machine, containing all possible initial moves. The items are written clearly on the board, showing the dot position and lookahead symbols.

  2. 2:00 – 5:00 02:00-05:00

    The instructor proceeds to build the transitions from state I0. He identifies transitions on terminals 's', 'A', 'B', 'b', and 'd'. The transition on 's' leads to state I1, which contains the completed item S' -> S., $. The transition on 'A' leads to state I2 with S -> A.a, $. The transition on 'B' leads to state I3 with S -> B.c, $. The transition on 'b' leads to state I4, which contains S -> b.Ac, $, S -> b.Ba, $, A -> .d, c, and B -> .d, a. The transition on 'd' leads to state I5, containing A -> d., a and B -> d., c. He carefully writes out the items for each new state, ensuring the lookahead symbols are correctly propagated from the parent state. This step-by-step derivation is essential for building the correct state machine. The closure of I4 is particularly important as it includes multiple productions.

  3. 5:00 – 7:53 05:00-07:53

    The lecture continues with the construction of the remaining states and the final parsing table. From state I4, transitions on 'A' and 'B' lead to states I6 (S -> bA.c, $) and I7 (S -> bB.a, $) respectively. Transitions on 'c' from I6 and 'a' from I7 lead to states I11 (S -> bAc., $) and I12 (S -> bBa., $). The instructor then draws the parsing table with rows for states I0 to I12 and columns for terminals a, b, c, d, and $. He fills in the action and goto entries. For example, I0 has goto entries for s, A, B, b, and d. I1 has an accept action on $. He fills in shift actions (S) and reduce actions (R) based on the completed items in each state, such as reducing A -> d in state I5 on input 'a'. The video concludes with a nearly complete parsing table ready for analysis, showing the full structure of the parser. The table entries are filled systematically.

The video provides a step-by-step walkthrough of SLR(1) parsing table construction. It starts with the fundamental grammar definition and moves through the critical steps of augmentation, state machine construction (DFA), and finally table population. The instructor emphasizes the importance of tracking lookahead symbols to resolve conflicts and correctly identify reduce actions. The progression from I0 to the final states I12 demonstrates the systematic nature of the algorithm, showing how each production rule contributes to the parsing structure. The final table serves as a complete specification for a parser to recognize strings generated by the given grammar.

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