Bottom Up Parser Fundamentals Part-2

Duration: 5 min

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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 lecture focuses on the practical application of bottom-up parsing, specifically using an LR parser to analyze a string. The instructor begins by defining a context-free grammar with productions S -> AA and A -> aA / b, displayed in the top left corner. He then proceeds to parse the specific input string "abab" by manually constructing a parsing table. The process involves drawing a parse tree to visualize the derivation structure, setting up columns for Stack, input (i/p), and Action, and then executing a sequence of shift and reduce operations. The video concludes with a theoretical overview of the components that make up a bottom-up parser, reinforcing the practical demonstration.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the grammar rules S -> AA and A -> aA / b, visible in the top left corner. He draws a parse tree in red ink to represent the structure of the input string "abab", showing S branching into two A nodes. He then sets up a three-column table labeled Stack, i/p, and Action with blue headers. The process begins with the stack initialized to `$` and the input buffer containing `a b a b $`. The instructor performs the first shift operation, moving 'a' from the input to the stack, resulting in Stack `$a` and i/p `b a b $`. He follows this with a second shift, moving 'b' to the stack, resulting in Stack `$ab` and i/p `a b $`. The first reduction occurs where 'b' is reduced to 'A' using the rule A -> b, updating the stack to `$aA`. A subsequent reduction applies A -> aA, changing the stack to `$A`. The action column explicitly records "shift" and "Redn (A -> b)".

  2. 2:00 – 4:45 02:00-04:45

    The parsing continues with the stack at `$A` and input `a b $`. The instructor shifts 'a' onto the stack, making it `$Aa`, and then shifts 'b', making it `$Aab`. A reduction follows where 'b' becomes 'A' (A -> b), resulting in Stack `$AaA`. Another reduction applies A -> aA, collapsing the stack to `$AA`. The final reduction uses the start symbol rule S -> AA, changing the stack to `$S`. The action column shows "acc" (accept) as the input buffer is empty and the stack contains the start symbol. The video ends with a slide titled "Model of an LR Parser," listing the three components: i/p buffer, Parse stack, and Parse table, alongside a diagram illustrating the driver program interacting with these components. The slide text "Bottom Up Parser consist of three components" is clearly visible.

The video effectively bridges theory and practice by walking through a complete parsing trace. It demonstrates how the abstract concepts of shift and reduce operations manifest in the parsing table, directly utilizing the grammar rules provided. The final slide reinforces the structural components (stack, buffer, table) that facilitate this process, providing a comprehensive overview of the LR parsing mechanism.

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