Compiler Design
What is Compiler Design?
A sequence of characters in the source program that matches a pattern for a token.
Key points
- Understand the role of lexical analysis in compilation.
- Learn how source code is converted into tokens.
- Familiarize with the use of regular expressions and finite automata.
- Identify different types of tokens.
Common exam trap
Confusing lexemes with tokens.
Definitions
- Term
Lexeme
- Meaning
A sequence of characters in the source program that matches a pattern for a token.
- Term
Token
- Meaning
A pair <token-name, attribute-value> representing a category of lexemes.
- Term
Pattern
- Meaning
A rule that describes the set of lexemes that can generate a token.
- Term
Regular Expression
- Meaning
A notation for describing sets of strings (patterns for tokens).
- Term
Finite Automaton (FA)
- Meaning
A computational model used to recognize patterns defined by regular expressions.
Learning objectives
Understand the role of lexical analysis in compilation.
Learn how source code is converted into tokens.
Familiarize with the use of regular expressions and finite automata.
Identify different types of tokens.
Understand the process of discarding irrelevant characters.
Prerequisites
Regular Expressions
Finite Automata (NFA and DFA)
Basic understanding of programming languages
Common mistakes
Confusing lexemes with tokens.
Incorrectly handling whitespace or comments.
Errors in regular expression definitions.
Inefficient implementation of the scanner (e.g., not using DFA).
Keywords
Lexical Analysis
Scanner
Token
Lexeme
Pattern
Regular Expression
Finite Automata
DFA
NFA
Compiler Design
Practice preview
Which of the following is NOT a phase of a compiler?…
easy
A context-free grammar (CFG) is used in which phase of a compiler?…
easy
Which of the following parsing techniques is a top-down parser?…
medium