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Questions and Answers
What does a semantic analyzer check for in a source program?
What does a semantic analyzer check for in a source program?
In the context of compilers, what is an important aspect of semantic analysis?
In the context of compilers, what is an important aspect of semantic analysis?
What integrates context-free grammars with attributes to aid in syntax-directed translation?
What integrates context-free grammars with attributes to aid in syntax-directed translation?
What is the primary purpose of intermediate code generation in compilation?
What is the primary purpose of intermediate code generation in compilation?
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Which phase of the compilation process focuses on optimizing code in terms of time and space?
Which phase of the compilation process focuses on optimizing code in terms of time and space?
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What is a significant difference between Operator-Precedence Parsing and LR Parsing?
What is a significant difference between Operator-Precedence Parsing and LR Parsing?
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In the context of compilers, what is the primary function of a semantic analyzer?
In the context of compilers, what is the primary function of a semantic analyzer?
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Which phase of compilation directly involves integrating context-free grammars with attributes?
Which phase of compilation directly involves integrating context-free grammars with attributes?
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What is an essential aspect of the intermediate codes produced by a compiler?
What is an essential aspect of the intermediate codes produced by a compiler?
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Which component of the compiler is responsible for optimizing the code in terms of time and space?
Which component of the compiler is responsible for optimizing the code in terms of time and space?
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What is a key purpose of type-checking in a semantic analyzer?
What is a key purpose of type-checking in a semantic analyzer?
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How are context-free grammars used in syntax analysis enhanced?
How are context-free grammars used in syntax analysis enhanced?
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What does an Operator-Precedence Parser primarily rely on?
What does an Operator-Precedence Parser primarily rely on?
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Which phase of compilation involves generating machine-independent intermediate codes?
Which phase of compilation involves generating machine-independent intermediate codes?
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Study Notes
Lexical Analyzer vs Syntax Analyzer
- Lexical analyzer deals with simple non-recursive constructs of a language.
- Syntax analyzer deals with recursive constructs of a language.
- Lexical analyzer recognizes the smallest meaningful units (tokens) in a source program.
- Syntax analyzer works on the smallest meaningful units (tokens) in a source program to recognize meaningful structures.
Parsing Techniques
- Parsing techniques are categorized into two groups: Top-Down Parsing and Bottom-Up Parsing.
- Top-Down Parsing: construction of the parse tree starts at the root and proceeds towards the leaves.
- Top-Down Parsing can be further divided into Recursive Predictive Parsing and Non-Recursive Predictive Parsing (LL Parsing).
- Bottom-Up Parsing: construction of the parse tree starts at the leaves and proceeds towards the root.
- Bottom-Up Parsing is also known as shift-reduce parsing and puts information about identifiers into the symbol table.
Lexical Analyzer
- Regular expressions are used to describe tokens (lexical constructs).
- Deterministic Finite State Automaton (DFA) can be used in the implementation of a lexical analyzer.
- Lexical analyzer simplifies the job of the syntax analyzer.
Syntax Analyzer
- A syntax analyzer creates the syntactic structure (generally a parse tree) of the given program.
- A syntax analyzer is also called a parser.
- The syntax of a language is specified by a Context Free Grammar (CFG).
- The rules in a CFG are mostly recursive.
- A syntax analyzer checks whether a given program satisfies the rules implied by a CFG or not.
Semantic Analyzer
- A semantic analyzer checks the source program for semantic errors and collects the type information for the code generation.
- Type-checking is an important part of semantic analyzer.
- Context-free grammars used in the syntax analysis are integrated with attributes (semantic rules) – the result is a syntax-directed translation, – Attribute grammars.
Intermediate Code Generation
- A compiler may produce an explicit intermediate codes representing the source program.
- These intermediate codes are generally machine (architecture independent).
- The level of intermediate codes is close to the level of machine codes.
Code Optimizer
- The code optimizer optimizes the code produced by the intermediate code generator in the terms of time and space.
- Faster code or target code that consumes less power.
Code Generation
- Produces the target language (Machine code) in a specific architecture.
- It depends on the computer architecture: i.e motherboard, cpu,…
- The target program is normally a relocateable object file containing the machine codes.
Other Applications
- Techniques used in compiler design can be applicable to many problems in computer science.
- Techniques used in a lexical analyzer can be used in text editors, information retrieval system, and pattern recognition programs.
- Techniques used in a parser can be used in a query processing system such as SQL.
- Many software having a complex front-end may need techniques used in compiler design.
- A symbolic equation solver which takes an equation as input uses techniques used in compiler design.
- Most of the techniques used in compiler design can be used in Natural Language Processing (NLP) systems.
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Description
Learn about the differences between syntax analyzer and lexical analyzer in programming language processing. Understand which constructs of a program should be recognized by the lexical analyzer and which ones by the syntax analyzer.
