Background

• Node.js REPL

Questions

• about Quiz 1 ?
• about A2 ?

Running JavaScript

In a file

• Create a new file ~/cs2613/labs/L08/hello-world.js
• Add some JavaScript code, save

    console.log("Hello world");

Running a script

• open a terminal, find the right directory

  $ node hello-world.js

• commit your file

In a Browser

• Start Firefox

• Open the "Web Console" with Ctrl-Shift-K (or navigate via the "hamburger menu" to "Web Developer -> Web Console" ).

• Select the tab "Console"

• Copy-paste the code in.

In the REPL

• Start up a node repl

  $ node

• Load your code into the repl

    > .load hello-world.js
  

• Evaluate some expressions

    > 1 + 1
    > "Hello " + "world!"
  

Translating Racket expressions into Javascript

• make a new file ~/cs2613/labs/L08/expr.js and fill in the JavaScript expressions equivalent to the given Racket expressions.

  • You can test your solutions with the REPL either by pasting in the expressions, or by using .load.

• note that if you want to run your code from the command line, you'll need to use console.log

    //(string-append "Hello\n" "world!")

    //(* (+ 1 2 3) 7)

    //(< 41 (* 6 7))

    //(equal? (* (+ 1 2 3) 7) 42)

    //(equal? "Spongebob" "Squarepants")

    //(and (equal? (* 6 7) 42) (equal? "Spongebob" "Squarepants"))

    //(equal? 42 (if (< 3 5) (* 6 7) "turnip"))

    // (or #t (/ 1 0))

    // (and #f (/ 1 0))

Quiz 1

• You will be given question(s) on paper.

• Test cases will be available on-line after the start of the quiz.

• Make sure you have any study materials in your home directory before the lab, as internet access will be restricted.

Before Next Lab