Deck 12: Formal Semantics

Question 1

Semantic domains having additional mathematical structure are called algebras.

Answer 1

True

Question 2

Semantic domains are the sets in which semantic functions take their values.

Answer 2

True

Question 3

It is possible to implement operational semantic rules directly as a program to get an executable specification.

Answer 3

True

Question 4

A least-fixed-point solution is a solution that has been made as flexible as possible.

Question 5

Programming is a goal-oriented activity.

Question 6

Formal specifications written in the operational or denotational style can be translated relatively easily into languages suitable for prototyping,such as Prolog.

Question 7

Language semantics should be dependent,such that each rule is derived from the other rules.

Question 8

Operational semantics cannot be used to define program behavior in terms of an abstract machine.

Question 9

There is a single,universal standard mathematical system for providing precise semantic descriptions of languages.

Question 10

In the sample small language presented in Chapter 12,the sets Program and Expression is an example of a syntactic domain.

Question 11

A formal specification method must be complete and consistent.

Question 12

Predicate transformers create new assertions out of old ones.

Question 13

An inference rule in logic indicates that when the premise is true,the conclusion is also true.

Question 14

Values of semantic functions in denotational descriptions will often be functions themselves.

Question 15

Axiomatic semantics define the semantics of a program by describing the effect its execution has on assertions about the data manipulated by the program.

Question 16

Reduction machines use reduction rules to specify how the control reduces the constructs of the language to a value.

Question 17

Semantic domains in denotational descriptions are never function domains.

Question 18

A denotational definition of a programming language contains a definition of the valuation functions.

Question 19

In the sample small language presented in Chapter 12,the sets Integer is an example of a syntactic domain.

Question 20

In the sample small language defined in Chapter 12,the empty environment defines all identifiers as 0.

Question 21

When an ambiguous grammar is used to define semantics,and the nonterminal symbols are replaced by single letters,____ syntax is in use.

A) dynamic
B) abstract
C) referential
D) variable

Question 22

The range of a semantic function is a ____.

A) syntactic domain
B) semantic domain
C) syntactic range
D) semantic range

Question 23

The theory of axiomatic semantics was developed as a tool for proving the correctness of programs and program fragments.

Question 24

An axiomatic specification of the semantics of a language construct implies that if the precondition is true,then the postcondition is true.

Question 25

____ semantics uses mathematical logic to define a language.

A) Axiomatic
B) Denotational
C) Operational
D) Logical

Question 26

A(n)____ specification allows us to construct a language interpreter directly from a formal specification.

A) abstract
B) executable
C) reduction
D) inference

Question 27

A(n)____ can be viewed as consisting of a program,a control,and a store or memory.

A) abstract machine
B) reduction machine
C) definitional compiler
D) semantic machine

Question 28

The value of a semantic function is specified by giving a semantic ____ corresponding to each grammar rule.

A) range
B) definition
C) value
D) equation

Question 29

____ are inference rules with no premise.

A) Axioms
B) Postulates
C) Theorems
D) Reduction rules

Question 30

The domain of a semantic function is a ____.

A) syntactic domain
B) semantic range
C) syntactic range
D) semantic domain

Question 31

The ____ rule expresses that reductions can be performed stepwise.

A) transitivity
B) sequential
C) stepwise
D) parallel

Question 32

____ semantics define a language by describing its actions in terms of the operations of an actual or hypothetical machine.

A) Denotational
B) Axiomatic
C) Theoretical
D) Operational

Question 33

To show that a while-statement is correct,we do not need to derive completely its weakest precondition,but only an approximation of it.

Question 34

The weakest precondition of a series of statements is the composition of the weakest preconditions of its parts.

Question 35

An identifier I is free if it is bound only by the existential quantifier.

Question 36

A translator is ____ to ensure that it produces behavior described in the language definition.

A) verified
B) validated
C) proven
D) vetted

Question 37

The ____ is an abstract machine whose control operates directly on a program to reduce it to its semantic value.

A) definitional compiler
B) abstract evaluator
C) reduction machine
D) elimination semantics

Question 38

____ semantics use mathematical functions on program components to specify semantics.

A) Operational
B) Denotational
C) Axiomatic
D) Mathematical

Question 39

____ interpreters can be used to specify the operational semantics for a language definition.

A) Operational
B) Definitional
C) Theoretical
D) Abstract

Question 40

In ____ semantics,a function describes semantics by associating semantic values to syntactically correct constructs.

A) axiomatic
B) denotational
C) operational
D) abstract

Question 41

The Law of ____ states that if a postcondition Q implies R then the weakest precondition of Q implies the weakest precondition of R.

A) the Excluded Miracle
B) Conjunction
C) Monotonicity
D) Disjunction

Question 42

The Distributivity of ____ concerns the behavior of the weakest precondition and the logical operator "and".

A) Conjunction
B) Monotonicity
C) Disjunction
D) Excluded Miracle

Question 43

The evaluation of expressions in the presence of an environment must include a(n)____ as a parameter.

A) reduction rule
B) arithmetic operator
C) environment
D) domain

Question 44

In denotational semantics,a semantic function is specified for each ____.

A) semantic domain
B) syntactic domain
C) environment
D) lifted domain

Question 45

Assertions about the situation just before execution are called ____.

A) preconditions
B) postconditions
C) executable assertions
D) requirements

Question 46

A function is a(n)____ if it takes a predicate as an argument and returns a predicate result.

A) axiomatic specification
B) predicate axiom
C) predicate transformer
D) expression transformer

Question 47

A semantic domain with the special value called bottom added to it is called a ____.

A) minimal environment
B) lifted environment
C) minimal domain
D) lifted domain

Question 48

Assertions about the situation just after execution are called ____.

A) preconditions
B) executable results
C) postconditions
D) verifications

Question 49

The Distributivity of ____ concerns the behavior of the weakest precondition and the logical operator "or".

A) the Excluded Miracle
B) Conjunction
C) Monotonicity
D) Disjunction

Question 50

The Law of ____ states that nothing a programming construct can do will make false into true.

A) Monotonicity
B) Conjunction
C) Disjunction
D) the Excluded Miracle