Problem regarding the order of evaluation

Assignment Help Basic Computer Science

Reference no: EM13963462

Order of Evaluation

In pure lambda calculus, the order of evaluation of subexpressions does not effect the value of an expression. The same is true for pure Lisp: if a pure Lisp expres- sion has a value under the ordinary Lisp interpreter, then changing the order of evaluation of subterms cannot produce a different value.

To give aconcrete example, consider the following section of Lisp code:

(define a ( ... ))

(define b ( ... ))... (define f (lambda (x y z) (cons (car x) (cons (car y) (cdr z))))) ... (f e1 e2 e3)

The ordinary evaluation order for the function call (f e1 e2 e3) is to evaluate the arguments e1 e2 e3 from left to right and then pass this list of values to the function f.

Give an example of Lisp expressions e1 e2 e3, possibly by using functions rplaca or rplacd with side effects, so that evaluating expressions from left to right gives a different result from that obtained by evaluating them from right to left. You may ?ll in speci?c declarations for a or b if you like and refer to a or b in your expressions. Explain brie?y, in one or two sentences, why one order of evaluation is different from the other.

Reference no: EM13963462

Questions Cloud

What mass of helium will be required. : A 1-liter container of nitrogen gas (N2) at a temperature of 23c is intially at a pressure of 1.25 atm. because of a slow leak the pressure falls to 1.15 atm 1 hour later what is the leak rate in molecules/second?

Overview of the symbolic interactionist perspective : Provide an overview of the "symbolic interactionist" perspective in sociology - what are its main ideas, how does it differ from other sociological approaches

Denotational semantics : The text describes a denotational semantics for the simple imperative language given by the grammar

Calculate the entropy change for each of the following : 10g of steam at l00°C and a pressure of one atmosphere condensing into water at the same temperature and pressure. (The latent heat of vaporization of water is 22571 Jg^-1).

Problem regarding the order of evaluation : In pure lambda calculus, the order of evaluation of subexpressions does not effect the value of an expression. The same is true for pure Lisp: if a pure Lisp expres- sion has a value under the ordinary Lisp interpreter, then changing the order of ..

What are your thoughts about the aim : What are your thoughts about the aim, results, and implications of the study in terms of the author's efforts to understanding and assessing the identified domains of sexual values highlighted in the study

How many photons are incident on surface breast tissue : The entrance exposure during a mammography examination is 100mR. Suppose the photon bean consists of photons each of energy 20 keV. How many photons are incident on a 1 cm^2 surface of breast tissue?

What is the average molar specific heat in this range : The molar specific heat of many materials at low temperatures is found to obey the Debye law C_v = A[T/theta]^3 where A is a constant equal to 1.94 x 10^3 Jmol^-1K^-1 and with the Debye temperature theta taking different values for different mater..

Selling an old a car : John called you late on Friday afternoon with a simple question. He is considering selling an old a car and wants to know what the tax implications will be.

User Account

All Pages