Functions and Roles of a Lexical Analyzer

Sep 17, 2024

Main Functions of Lexical Analyzer

Introduction

  • The lexical analyzer is one of the first phases of a compiler.
  • It is used to transform a high-level program into tokens.

Function of Lexical Analyzer

  • Input: Source program (high-level language)
  • Output: Stream of tokens.
  • The lexical analyzer reads the program character by character.

Types of Tokens

  • Tokens can be divided into different categories:
    • Identifiers
    • Separators

Parser and Tokens

  • The parser (Syntax Analyzer) receives tokens from the lexical analyzer.
  • Various types of information are needed to identify tokens.
  • A parse tree is generated as output.

Symbol Table

  • The symbol table is a data structure that stores information about all identifiers and their types.

Task Details

  • Example: a = b + c
    • Tokens: id = id + id
    • Here id represents identifiers.

Other Important Tasks

  • Remove white spaces and tabs.
  • Remove comments.
  • Identify errors if any and provide the line number of the error.

Conclusion

  • The lexical analyzer plays a significant role for a compiler.
  • Watch more videos to learn more about it.
  • Video content is available for related topics.

These notes provide a summary of the main functions and procedures of the lexical analyzer, allowing students to easily understand how it works.