Especially functional programming conceptsuse one language

CS 3520/6520
Programming Languages

Fall 2021

an object-oriented language

a functional language

lexical scope		recursion
λ-calculus	objects

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CS 3520/6520 Programming Languages This course is about programming language concepts

Formal prerequisite: CS 3500
Informal prerequisite: more programming experience than that

Grading:
• Weekly homework (55%)
• Two mid-term exams (30%)
• Extended fnal homework (10%)
• Online quizzes (5%)

• Watch the videos before class

• Take the quiz before class
≥ 60% over semester ⇒ 100%
no late quizzes

• Learn concepts by implementinginterpreters

1+2

1��1�

Racket and Plait
• Implement interpreters using Plait, a variant of Racket Historically: Lisp⇒Scheme⇒Racket⇒Plait

PLAI = Programming Languages: Application and Interpretation, a textbook

Preview: Plait Tutorial

http://docs.racket-lang.org/plait/index.html

{ x=0 x>0 0 1
x<0 -1

(cond
[(<x0)-1]
[(=x0)0]
[(>x0)1])

'(123)'(fx)

2��31

`{define{fx}

{+x1}}

(test (area(circle2))
12.56)
(test (area(rectangle34))
12)

(define-type Shape
(circle[radius:Number])
(rectangle[width:Number]
[height:Number])
(adjacent[left:Shape]
[right:Shape]))

(define (areas)
(type-case Shapes
[(circler)(*3.14(*rr))]
[(rectanglewh)(*wh)]
[(adjacentlr)(+(areal)
(arear))]))