Chapter 15

Question 1

What is imperative language design based on?

Answer 1

von Neumann architecture with efficiency as primary concern

Question 2

What is functional language design based on?

Answer 2

Mathematical functions

Question 3

What are functional side effects?

Answer 3

When a function changes a parameter or a global variable

Question 4

What is the problem with functional side effects?

Answer 4

Unpredictable, Concurrency issues

Question 5

How to solve functional side effects?

Answer 5

1) No 2 way parameters, No non-local references in functions. but it is very inflexible

2) Demand fixed operand evaluation order. limits some complier optimizations

Question 6

When does a program have referential transparency?

Answer 6

Any 2 expressions that are equivalent can be substituted for one another and it doesn’t affect the action.

There are no functional side effects

Question 7

What is the advantage of referential transparency?

Answer 7

semantics are easier to understand

Question 8

Are Pure Functional Languages referentially transparent? and why?

Answer 8

Yes. No global variables. parameter values are constants. functions cannot have state, value of function depends only on parameters

Question 9

What is the objective of functional language designs?

Answer 9

mimic math functions as closely as possible

Question 10

What are the LISP Data Objects and Structures?

Answer 10

Only consists of atoms and lists

2 types of atoms (symbols and numeric literals)

List = sequence of atoms or sublists

Question 11

What does Scheme and Lisp have in common?

Answer 11

They use the same atoms and lists

Question 12

What is Scheme interpreter interactive mode?

Answer 12

Mode that allows you to type code in line by line rahter than programming in an editor

Question 13

Scheme interpreter is just a Scheme function?

Answer 13

Yes

Question 14

How are functions evaluated?

Answer 14

Parameters (in no order)
values of parameters substituted into the function body
Value of last expression evaluated in the body is the value that the function defines

Question 15

What are the Primitive Numeric Functions

Answer 15

+,-,*,/,abs,sqrt,remainder,min,max

Question 16

Which primitive numeric functions cannot accept multiple parameters?

Answer 16

abs,sqrt,remainder

Question 17

What are lambda functions used for?

Answer 17

Nameless functions

Question 18

how many parameters can lambda functions have?

Answer 18

any number of parameters

Question 19

how do you bind names to lambda expressions?

Answer 19

(define (square x) (* x x))

Question 20

how do you bind a name to the value of an expression

Answer 20

(define pi 3.142) or (define two_pi (* 2 pi))

Question 21

Hoe is the evaluation process for defined different?

Answer 21

Since the 1st parameter is a name and not a parameter it is not evaluated (otherwise it would be evaluated as undefined)

Question 22

How do you output a expression in Scheme?

Answer 22

(display expression)

Question 23

what is used for true and false in scheme?

Answer 23

t and #f (or () for false)

Question 24

What are the predicate values for numbers with multiple parameters?

Answer 24

=, <>, > ,<, >= and <=

Question 25

Predefined predicate functions for numbers, single value test.

Answer 25

even?,odd?,zero?,negative?,positive?

Question 26

what does <> mean?

Answer 26

not equals

Question 27

how does a if function look like?

Answer 27

(if predicate then_exp else_exp)
example
(define (divide number denom)
(if (<> denom 0)
(/ number denom) // returns this if true
0 // returns this if false
)
)

Question 28

what is the cond function?

Answer 28

conditional control flow function

Question 29

how does the cond function work?

Answer 29

“Accepts” the 1st expression that evaluates to true.
if no expression is true it goes to the else expression if there is one

Question 30

how is repetition handled?

Answer 30

through recursion

Question 31

how is a list created?

Answer 31

‘(A B) or (quote (A B))

Question 32

how does “list” work in scheme?

Answer 32

(list ‘A ‘B ‘C) yields (A B C)
(list ‘A ‘B ‘(C D)) yields (A B (C D ))

Question 33

How do you get the 1st element of a list?

Answer 33

(car list)

Question 34

how do you get the remainder of a list after its 1st element has been removed?

Answer 34

(cdr list)

Question 35

what does cons do?

Answer 35

outs the 1st oarameter into the 2nd parameter (a list) to make a new parameter

Question 36

examples of cons

Answer 36

(cons ‘A ‘(B C)) = (A B C)
(cons ‘(A B) ‘(C D)) = ((A B) C D)
(cons ‘() ‘(A B)) = (() A B)
(cons ‘A ‘B) = (A . B)
(cons ‘(A B) ‘C) = (( A B) .C)

Question 37

How many parameters does list? take?

Answer 37

1

Question 38

What does the null? predicate function do?

Answer 38

Checks if the list is empty ( (()) is not an empty list)

Question 39

what does eqv? do?

Answer 39

checks if 2 values are the same.
Doesnt work for lists but does work for (eqv? ‘A ‘A)

Question 40

what does eq? check?

Answer 40

if the 2 parameters are the same object in memory (for 2 list parameters or numeric atoms the result is not reliable)

Question 41

What is the general form of let?

Answer 41

(let ((name1 exp1)(name2 exp2))body that uses the names in the bindings)

Question 42

what does the let construct yield?

Answer 42

the value of the last application

Question 43

What does the member function do?

Answer 43

Checks if an atom is in a simple list

Question 44

With which function do you check if 2 lists are equal?

Answer 44

equalsimp

Question 45

how is equal different from equalsimp?

Answer 45

equalsimp = atoms, equal = atoms + lists

Question 46

What does (append lis1 lis2) yield?

Answer 46

all elements of list 1 followed by all elements of list 2

Question 47

When is a recursive function tail recursive?

Answer 47

When the recursive call is the last operation in the function

Question 48

What does mapcar do?

Answer 48

“Does” the function to everything in the list
(define (add-two number)
(+ number 2))

(mapcar add-two ‘(1 3 5 7))

results in (2 5 7 9)

Question 49

What is a function that builds code

Answer 49

A function that can build code that can be executed

Question 50

What is LISP used for?

Answer 50

AI

Question 51

What is scheme used for?

Answer 51

To teach intro to programming