Chapter 4

Question 1

To help in semantic analysis we need two tools

Answer 1

Semantic rules(definitions)
Semantic actions(translations)

Question 2

Semantic analysis

Answer 2

• checks the src program for semantic error
• type checking
• Example: Array indexing using floats

Question 3

Semantic analysis uses … from the syntax analysis

Answer 3

hierarchical structure to identify operators and operands

Question 4

Semantic analyzer judgment

Answer 4

Example: int a = “value”; is syntactically and lexically correct but semantic analyzer throws an error

Question 5

Semantic analyzer tasks

Answer 5

• Scope resolution
• Type checking
• Array bound checking

Question 6

Semantic errors

Answer 6

• Type mismatch
• Undeclared vars
• Reserved identifier use
• Multiple declaration of variable
• Parameter and argument mismatch

Question 7

Syntax directed translation

Answer 7

• refers to a method a compiler implementation where the source language translation is completely driven by the parser

Question 8

Syntax directed translation is directed by

Answer 8

Context free grammars

Question 9

Attributed grammars

Answer 9

Augment CFG with information to control semantic analysis and translation process

Question 10

Steps in syntax directed translation

Answer 10

input string -> parse tree -> dependency graph -> eval of semantic rules

Question 11

Output action of Syntax directed translation

Answer 11

• computation of values for variable belonging to the compiler
• generate of intermediate code
• printing an error diagnostic
• placement of values in table

Question 12

Syntax directed definition

Answer 12

semantic rule in which each variable adds extra variable. And each production adds semantic rule