Lexical Analysis
Lexical Analysis is an essential phase of the compiler that transforms raw source code into structured tokens required for parsing. It involves the identification of tokens through a meticulous scanning of the input stream, employing techniques like regular expressions and deterministic finite automata for pattern recognition. This chapter explains the roles, responsibilities, and mechanisms involved in lexical analysis while also introducing tools such as LEX and Flex which automate the lexer generation process.
Sections
Navigate through the learning materials and practice exercises.
What we have learnt
- Lexical analysis serves as the first step in compilation, converting raw input into meaningful tokens.
- Regular expressions and finite automata are foundational in identifying and categorizing lexemes into tokens.
- Tools like LEX and Flex streamline the development of lexical analyzers, enhancing efficiency and accuracy in the compilation process.
Key Concepts
- -- Lexeme
- A lexeme is the actual sequence of characters in the source code that matches the pattern of a token.
- -- Token
- A token is a representation of a category of lexemes, consisting of a token name and an optional attribute value.
- -- Deterministic Finite Automata (DFA)
- A DFA is a computational model used to recognize patterns described by regular expressions through its states and transitions.
- -- Regular Expressions
- Regular expressions are formal notations used to describe the structure of tokens and patterns in textual data.
- -- LEX/Flex
- LEX and its modern counterpart Flex are tools that automatically generate lexical analyzers from high-level specifications defined using regular expressions.
Additional Learning Materials
Supplementary resources to enhance your learning experience.