Designing LR(O) Parser Part-5

Duration: 4 min

This video lesson is available to enrolled students.

Return to /learn/HPSC-PGT-COMPUTER-SCIENCE/compiler-design/syntax-analysis-bottom-up/intro-to-bottom-up-lr0/asset-designing-lro-parser-part-5 after enrolling

Inside: a video lesson and guided study material.

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 lecture provides a detailed explanation of "Conflicts in LR(0) parser," a fundamental topic in compiler design. The instructor categorizes conflicts into two distinct types: "SR Conflicts (Shift Reduce)" and "RR Conflicts (Reduce Reduce)." He explains the specific conditions required for each conflict to occur within the states of a Deterministic Finite Automaton (DFA). For SR conflicts, he notes that they arise when a state contains both final and non-final items. For RR conflicts, he explains they happen when a state contains more than one final item. The lecture concludes by defining an "LR(0) Grammar" as an unambiguous grammar where the parse table is free from these multiple entries, ensuring deterministic parsing.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor starts by introducing the slide titled "Conflicts in LR(0) parser." He highlights the bullet points for "SR Conflicts (Shift Reduce)" and "RR Conflicts (Reduce Reduce)." He focuses on the SR conflict section, reading the text: "If the state of DFA contains both final & non-final items, then it is S-R conflicts." He points to the example rules A -> alpha.x beta (labeled as shift) and B -> delta . (labeled as reduced). To visualize this, he circles the production A -> alpha.x beta and the production B -> delta . with a red pen. He then draws a horizontal line with vertical dividers to represent the parse table or state structure, indicating where the shift and reduce actions would clash. He emphasizes that the presence of x (a terminal) necessitates a shift, while the dot at the end of B necessitates a reduction.

  2. 2:00 – 4:05 02:00-04:05

    The instructor transitions to the second type of conflict, "R-R Conflict." He reads the definition: "If the same state contains more than one final item, then it is R-R Conflict." He points to the example rules A -> alpha . and B -> alpha .. Although the text next to A says "(x is terminal, shift)", the instructor circles both A -> alpha . and B -> alpha . to show they are both final items causing a conflict. He then moves to the final bullet point defining "LR(0) Grammar." He reads the text: "An unambiguous grammar LR(0) parse table is free from multiple entries, i.e. free both SR & RR conflicts, is LR(0) grammar." He circles the title "Conflicts in LR(0) parser" again to summarize the entire topic covered in the session.

The lecture progresses logically from identifying specific conflict types to defining the grammar that avoids them. By visually circling the conflicting production rules and drawing diagrams, the instructor clarifies the abstract concepts of shift-reduce and reduce-reduce conflicts. The final definition establishes that a grammar is LR(0) only if its parse table contains no such ambiguities.

Loading lesson…