Abstraction Elements of a Language(or Engineering Design) Primitives, means of combination means of abstraction What weve seen Procedural Abstraction. ambda-captures common patterns and Deep question

Slide 32.1.1 We have spent some time looking at computational objects that rency and asynchronous computing are built around the use of local state variables and methods for Object oriented approaches lose \referential transparency Referential transparency means equal expressions

Slide 17.5.1 Streams-a different way of structuring Now, let's look at one example in which changing the computation evaluation model allows us to explore a very different kind of computational problem. Our goal is to show how a smal

signment exp en ((definition? exp)(eval-definition exp env)) ((if? exp)(eval-if exp env)) ((lambda? exp) (make-procedure (lambda-parameters exp)(lambda-body exp) env)) ((begin? exp)(eval-sequence (begin-actions exp)env)

1. Arithmetic calculator 6 (define (eval exp) 8 ((number? exp) exp) ((sum? exp (eval-sum exp))

Slide 15.1.1 Why do we need an interpreter? Our goal over the next few lectures is to build an interpreter which in a very basic sense is the ultimate in programming, since doing so will allow us to define our language

Slide 14.1.1 Elements of ooP Last time we introduced the idea of object oriented systems Today, we want to build on those basics, looking at how we can expand object-oriented systems to deal with hierarchies of objects, to leverage the commonality of methods between

Text 1 Data Structure Exercises 1. Multiple choices (1)The attributes of the stack are(A B C. queue D. built into their circuitry

Section I Structure and Vocabulary Part A Directions: Beneath each of the following sentences, there are four choices marked [A], [C]and [D]. Choose the one that best completes the sentence. Mark your answer on ANSWER SHEET 1 by blackening the corresponding letter in the brackets with a pencil. (5 points) Example

TEACHING PLAN Unit 3 Paradise Lost Teaching Objectives Master the key words and structures, and learn something about the rainforest The students are required to understand the importance of environmental protection Key Points Vocabulary: absorb, atmosphere, contain, economic establish, greenhouse Impression Process, purchase, rainforest, resource, solution, vary, speed up, no more than Carbon dioxide Structure: It is the modern world that has speeded up It is people themselves who are the biggest cause Language points 1. description: an account of what someone or something is like