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Questions and Answers
What are Formalisms known as when the attribute evaluation order can be fixed at compiler construction time?
Strongly Non-Circular Syntax Directed Definitions
How can Synthesized Attributes be evaluated in a bottom-up parser?
By keeping values in the stack
What does an L-Attributed Definition contain?
In L-Attributed Definitions, which attributes do inherited attributes depend on?
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What is a translation scheme in the context of a context-free grammar?
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A ________ translation scheme converts infix expressions to postfix expressions.
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What is the purpose of semantic analysis in a compiler?
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What does semantic analysis involve?
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Semantic analysis can be done during parsing.
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Syntax-Directed Translation is the combination of production and ______ rules.
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Match the following attribute types with their definitions:
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Study Notes
Introduction to Semantic Analysis
- Semantic analysis is the third phase of a compiler, after lexical analysis and syntactic analysis
- Its purpose is to analyze the meaning of the source code and ensure it is legal
- This phase checks for errors such as undeclared variables, type mismatches, and scope violations
What Does Semantic Analysis Involve?
- Type checking: ensuring data types are used consistently
- Label checking: ensuring labels exist and are referenced correctly
- Flow control checks: ensuring control structures are used correctly
- Uniqueness checks: ensuring certain names are unique
- Logical checks: ensuring the program is logically correct
Syntax-Directed Translation (SDT)
- SDT is a method for specifying translations of programming language constructs
- It involves associating attributes with grammar symbols and specifying semantic rules for computing attribute values
- There are two types of attributes: synthesized (computed from child nodes) and inherited (computed from parent or sibling nodes)
Syntax-Directed Definitions (SDD)
- SDD is a representation formalism for semantic analysis
- It involves specifying grammar productions with associated semantic rules for computing attribute values
- SDD can be implemented using dependency graphs or translation schemes
S-Attributed Definitions
- S-Attributed Definitions are a type of SDD that uses only synthesized attributes
- Evaluation order is determined by a bottom-up traversal of the parse tree
- Example: arithmetic expressions with synthesized attributes for values
L-Attributed Definitions
- L-Attributed Definitions are a type of SDD that uses both synthesized and inherited attributes
- Evaluation order is determined by a combination of bottom-up and top-down traversals of the parse tree
- Example: type checking with inherited attributes for type information
Translation Schemes
- Translation schemes are a way to specify the order of semantic actions and attribute evaluations
- They involve inserting semantic actions into the right-hand side of productions
- Example: a translation scheme for converting infix expressions to postfix notation
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Description
This quiz covers the concepts of semantic analysis, syntax-directed translation, and attribute grammars in compiler design.
