Designing LR(O) Parser Part-2

Duration: 7 min

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Module outline

  1. HPSC Interview Preparation: Interview Preparation
  2. Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis, DSA using Python
  3. Data Structure & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Sorting Algorithms, Minimum Spanning Trees, Time Complexity Analysis, Graph Theory, Shortest Path Algos
  4. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
  5. Computer System & Organisation: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  6. 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, Transaction Management, Concurrency Control
  7. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling
  8. Digital Logic & Circuits: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  9. Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Pushdown Automata & CFG, Turing Machines, Moore & Mealy Machines
  10. Compiler Design: 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
  11. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Data Warehousing & Mining
  12. Introduction to Emerging Trends: Emerging Tech Trends
  13. Digital Society & Cyber Law: Society, Law & Ethics
  14. HPSC PGT Previous Year Paper:
  15. HPSC Assistant Professor Previous Year Paper:
  16. Live Sessions: HPSC Live Sessions, EMRS TGT/PGT Live Class
  17. Full Mock Test:
  18. HPSC PGT - MOCK Test Series:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video features an educational lecture by Sanchit Jain from Knowledge Gate on constructing a parsing table for a specific context-free grammar. The grammar presented is A' -> A and A -> aA / b. The instructor begins by displaying a state diagram (DFA) that represents the LR(0) items for the grammar. He systematically explains the transitions between states I0 through I4. He then proceeds to construct a parsing table with columns for 'Action' (terminals a, b, $) and 'Goto' (non-terminal A). The lecture covers filling in shift, reduce, and goto actions based on the items in each state, culminating in a completed table and a brief mention of a sample string "abab".

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor starts by reviewing the state diagram. State I0 contains items A' -> .A, A -> .aA, and A -> .b. He points out transitions: 'A' leads to I1, 'a' leads to I2, and 'b' leads to I3. State I1 contains A' -> A.. State I2 contains A -> a.A, A -> a.aA, and A -> a.b. State I3 contains A -> b.. State I4 contains A -> aA.. The instructor highlights the transitions and the items within each box to establish the foundation for the parsing table. He specifically points to the items in I0 and traces the arrows to I1, I2, and I3.

  2. 2:00 – 5:00 02:00-05:00

    He draws a table with headers 'Action' (sub-columns a, b, $) and 'Goto' (sub-column A). He starts filling the row for I0. On input 'a', he writes S2 (shift to state 2). On input 'b', he writes S3 (shift to state 3). On input 'A' in the Goto column, he writes 1. For row I1, since it contains A' -> A., he marks the '$' column as "Accept". He explains that this indicates successful parsing of the start symbol. He fills the first row completely before moving to the next.

  3. 5:00 – 6:53 05:00-06:53

    He continues filling the table. For row I2, on 'a' he writes S4, and on 'b' he writes S3. For row I3, which has A -> b., he writes R2 (reduce by production 2) in the action columns. For row I4, which has A -> aA., he writes R1 (reduce by production 1) in the action columns. Finally, he writes "abab" at the bottom as an example string to be parsed using the constructed table. The table is now mostly complete with shift and reduce actions filled in.

The lecture demonstrates the direct mapping between the LR(0) state diagram and the parsing table. Shift actions correspond to transitions on terminals, Goto actions correspond to transitions on non-terminals, and Reduce actions correspond to states containing completed items (dot at the end). The process transforms the theoretical state machine into a practical parsing mechanism. The instructor uses the example string "abab" to hint at the next step of parsing the string.

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