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.

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