Parsing Algorithms In Compiler Design

Top down parsing and Bottom up parsing

What you'll learn

Different types of parser in compiler

Recursive Descent Parsing

Predictive Parser

Operator Precedence Parser

Simple LR Parser

LALR and CLR parsers

Requirements

No prerequisites are there for this course.

Description

Compiler design is a crucial aspect of programming language development, responsible for translating high-level source code into machine code that can be executed by a computer. One of the key phases in this process is parsing, where the compiler analyzes the syntactic structure of the source code to create a parse tree or abstract syntax tree. Various parsing algorithms are employed to achieve this, each with its strengths and weaknesses. This article explores the fundamentals of parsing algorithms in compiler design, shedding light on their significance and characteristics.Top-Down Parsing:Top-down parsing is an approach where the parsing process begins with the highest-level grammar production and gradually explores the lower-level productions until the entire parse tree is constructed. Common top-down parsing techniques include Recursive Descent Parsing and LL Parsing. Recursive Descent Parsing involves creating recursive procedures to match grammar rules, while LL Parsing utilizes a table-driven approach based on the LL(k) grammar class.Bottom-Up Parsing:In contrast, bottom-up parsing builds the parse tree from the leaves (tokens) to the root. Shift-Reduce Parsing and LR Parsing are popular bottom-up parsing techniques. Shift-Reduce Parsing involves shifting tokens onto a stack and then reducing them based on predefined grammar rules, while LR Parsing employs a state machine and a lookahead buffer to determine valid reductions.LR Parsing is a widely used bottom-up parsing technique with several variants, including SLR, LALR, and LR(1). These variants differ in the complexity of their parsing tables and the amount of lookahead information they consider. SLR (Simple LR) Parsing and LALR (Look-Ahead LR) Parsing are more efficient in terms of table size, while LR(1) Parsing offers greater parsing power at the cost of increased table complexity.

Overview

Section 1: Introduction to parser

Lecture 1 Context Free Grammar, Derivation, Parse Tree

Lecture 2 Introduction to parser in Compiler Design

Lecture 3 Types of parser

Section 2: Top Down Parser

Lecture 4 Recursive Descent Parsing

Lecture 5 Left Recursion and Left Factoring Elimination

Lecture 6 FIRST of Variable

Lecture 7 FOLLOW of Variable

Lecture 8 Predictive Parser

Lecture 9 Non LL1 Grammar

Lecture 10 Non Recursive Predictive Parser

Section 3: Operator Precedence Parser

Lecture 11 Leading and Trailing

Lecture 12 Operator Precedence Parsing table construction

Lecture 13 Parsing an input

Section 4: Bottom up Parser

Lecture 14 Handle, Handle Pruning

Lecture 15 Shift Reduce Parser

Lecture 16 Simple LR Parser (SLR)

Lecture 17 SLR parser Example

Lecture 18 SLR parser Example

Lecture 19 Canonical LR Parser

Lecture 20 LALR Parser

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