Lab 1

Refer to the lab handout lab1.pdf for details about the assignment. This file provides some information to help you get started with setting up your development environment for the labs.

Important Files

├──  (this file)
├── grader  (autograder project files)
├── koans  (Scala Koans)
├── src
│   ├── main
│   │   ├── java
│   │   └── scala
│   │       ├── Lab1.scala  (implementation template to submit)
│   │       └── jsy
│   │           └── lab1
│   │               └── ast.scala  (JavaScripty AST classes)
│   └── test
│       ├── java
│       └── scala
│           └── Lab1Spec.scala  (ScalaTest unit tests)
└── testjsy  (some JavaScripty test cases)
    ├── test01_arith.jsy
    └── test02_divbyzero.jsy

Scala Development Tools

The current version of Scala is 2.10.3 at the start of Spring 2014. We standardize to this version.

We will support Scala IDE for Eclipse for Scala development in this course. You are welcome to use any development environment, but we may not be able answer questions in your particular environment.

To install Scala IDE, first download and install Eclipse. The standard package is sufficient. For Spring 2014, we suggest installing Eclipse Kepler (the latest version). Then, follow the directions for installing Scala IDE.

Eclipse Import

To import the Lab 1 project files into Eclipse, go to

File > Import > Existing Projects into Workspace (under General)

and then select

Select archive file:

and browse to the that you downloaded from the course website.

Command-Line Tools

While not required if you have installed Scala IDE, you may also want to install the command-line Scala compiler and tools. If you would like to build the project on the command-line, you should install sbt. Scala and sbt is available in many OS-specific package managers.

For your convenience, an sbt script (build.sbt) is included. You can issue the following commands to compile, run and test your code:

$ sbt run

runs your project (after compiling).

$ sbt clean

deletes the previous compilation.

It is often convenient to run sbt interactively

$ sbt

and then run via

> run

at the sbt prompt.

Scala Interpreter

From the command-line, you can start the scala interpreter using the command

$ scala

and can import the functions in your lab in the following way

scala> import Lab1._

Note that you will need to run the scala interpreter in the same directory as the compiled version (lab1/bin/).

In Scala IDE, you can start a Scala interpreter with the project files available by selecting

Window > Show View > Scala Interpreter


We will be using the ScalaTest framework for unit testing. Using this framework, we practice test-driven development (TDD), a standard practice in industry.

We suggest you install the ScalaTest plugin for Scala IDE.

You do not need to explicitly download ScalaTest.

We provide some unit tests in Lab1Spec.scala to drive your implementation. To run tests, right-click on the file and select

Run As > ScalaTest - File

You can also run tests via

$ sbt test

JavaScripty Interpreter

You can run your JavaScripty interpreter with a file (e.g., tests in testjsy/) in Eclipse by right-clicking on Lab1.scala by setting up a Run Configuration:

Run As > Run Configuration ...

For quick experimentation, it is more convenient to use the Scala Interpreter window.


A part of your lab grade is determined by passing a set of grading tests. To run the autograder, do

$ sbt "project lab1-grader" run

For Lab 1, the grading tests are those in Lab1Spec.scala. In future labs, these test sets may diverge.