This zipfile contains the assignments for CSC447. It includes

• play - A folder for your scratch files and experiments
• src/main/scala - A folder for homework
• src/test/scala - A folder for homework test files - Do not edit
• build.sbt - A build file - Do not edit

sbt will create additional folders (project and target). If you delete these, sbt will recreate them.

VSCode creates hidden folders (.bloop, .bsp, .metals, .scalafmt.conf, .vscode). If you delete these, VSCode will recreate them.

Software Requirements

You will need to install Java, Scala, and VSCode. Follow the instructions here.

Using VSCode

Set up Scala in VSCode:

• Install the Scala (Metals) Extension
  • Select View -> Extension
  • Search Metals
  • Install Scala (Metals)
• Open a workspace for this class
  • Select File -> Open Folder
  • Choose the scala-hw Folder, which contains this file
  • Make sure to choose the Folder, not any file inside of it
  • VSCode should detect sbt
  • When prompted, select Import Build (This may happen several times)
  • If you get an error, restart VSCode – You shouldn’t have to repeat this process
• Get formatting working
  • Open a .scala file in the editor
  • Select View -> Command Palette...
  • In the Palette, Type Format Document
  • VSCode should prompt you to create a format
  • When prompted, select Create .scalafmt.conf
  • In the Palette, try Format Document again
  • If it does not work, restart VSCode – I had to do this on one machine

sbt

sbt is used to compile and test the Scala assignments. It is installed when you install Scala. sbt will take care of downloading the correct version of Scala for you. You will need to be connected to the Internet when you do this.

sbt runs in a Terminal.

• To start a Terminal in VSCode, select Terminal -> New Terminal

You can also use a Terminal window outside of VSCode. Any shell will work: bash, CMD.exe, Powershell, etc.

From a Terminal, launch sbt using the command you set up during sbt installation. This is usually just sbt. For example:

terminal$ sbt
[info] welcome to sbt ... (Amazon.com Inc. Java ...)
[info] loading settings for project hw from build.sbt ...
[info] set current project to CSC447 ...
[info] started sbt server
sbt> 

NOTE: you must be in the directory that contains the file build.sbt and has the directory src when you run the sbt command. Use cd to change to that directory if necessary. The build.sbt file contains instructions for building and testing the project. It will compile code into a new target subdirectory.

You need to have Internet connectivity when you initially ask sbt to compile and test in order to download to libraries.

Launch Scala Console from sbt

To launch Scala from sbt, run:

sbt> console
scala>

To exit Scala and return to sbt, enter:

scala> :quit
sbt>

You will have access to code in src/main/scala. For example, you can run:

scala> import fp1.*
scala> fact (5)

You can run files in the play directory by loading them:

scala> :load play/README.scala

Compiling with sbt

To compile the Scala source code with sbt, run:

sbt> compile

To continuously compile, run:

sbt> ~compile

For the assignments, you may prefer to simply run the tests as you go. However, for tricky exercises, you may wish to edit source code, compile it from sbt, and try it out in the Scala console.

Testing with sbt

From sbt, you can run various commands to compile and run the tests under src/test.

When you ask sbt to run any tests, it will automatically compile your source code and the test code first (if it does not appear to do so, ensure that you have saved your source code file in your text editor!).

To run all tests from sbt:

sbt> test

To run all tests for the first functional programming assignment from sbt:

sbt> testOnly fp1tests

The names of the tests for the other Scala assignments can be found by looking under src/test.

To run the tests for exercise 5 from the first functional programming assignment, run the following command from sbt:

sbt> testOnly fp1tests -- -n fp1ex05

The most useful mode is to prefix the test command of your choice with ~ (the tilde symbol). That will cause sbt to continually compile and test your code whenever it detects changes have been made. That is, for the first functional programming assignment use:

sbt> ~testOnly fp1tests

Homework Instructions

For all assignments, you must submit source code that compiles without error. Submissions where the source code does not compile will receive 0 points. If source code compiles correctly, partial credit may be given for assignments where some of the tests fail. For Scala assignments, you can confirm that your source code compiles correctly by running the following command in your repository directory:

sbt> compile

For each assignment, you will hand in a single source code file on D2L. Do not hand in a zip file.