introprog

This is the documentation of the introprog Scala Library with beginner-friendly utilities used in computer science teaching at Lund University. The open source code is hosted at https://github.com/lunduniversity/introprog-scalalib.

Package contents

• introprog.PixelWindow for simple, pixel-based drawing.

• introprog.PixelWindow.Event for event management in a PixelWindow.

• introprog.IO for file system interaction.

• introprog.Dialog for user interaction with standard GUI dialogs.

• introprog.BlockGame an abstract class to be inherited by games using block graphics.

• introprog.examples with code examples demonstrating how to use this library.

How to use introprog-scalalib

You need Scala installed, Scala 3.8.3 or later recommended.

Start a repl session with introprog

The Scala repl (read-evaluate-print-loop) allow you to run Scala-lines one at a time. Start the Scala repl with introprog available like so:

scala repl . --dep "se.lth.cs::introprog:1.5.0" --jvm 21

Note the dot after repl, which means "this dir" making all scala code in the current dir available in the repl.

Now you can open a drawing window by typing this after the scala> prompt:

val w = introprog.PixelWindow()
w.drawText("Hello introprog.PixelWindow!", x = 100, y = 100)

Use introprog in your Scala programs

Or add these magic comment lines starting with //> in the beginning of your Scala 3 file:

//> using scala 3.8.3
//> using dep "se.lth.cs::introprog:1.5.0"

You can use the latest stable Scala version, or any version from at least Scala 3.3.7.

You run your code in the current dir with scala run . (note the ending dot, meaning "this dir")

If your program looks like this:

//> using scala 3.8.3
//> using dep "se.lth.cs::introprog:1.5.0"

@main def MyMain =
  val w = introprog.PixelWindow()
  w.drawText("Hello introprog.PixelWindow!", x = 100, y = 100)

You should see green text in a new window after executing:

scala-cli run .

See: api documentation for PixelWindow

Using sbt

If you have sbt installed at least version 1.12.9 then you can put this text in a file called build.sbt

scalaVersion := "3.8.3"  // or any Scala version from at least 3.3.7
libraryDependencies += "se.lth.cs" %% "introprog" % "1.5.0"

When you run sbt in a terminal, with the above in your build.sbt, the introprog lib is automatically downloaded and made available on your classpath. Then you can do things like:

sbt> console
scala> val w = new introprog.PixelWindow()
scala> w.fill(100,100,100,100,java.awt.Color.red)

Manual download

You can also manually download the latest jar file from here:

Lund University: http://www.cs.lth.se/pgk/lib

GitHub: https://github.com/lunduniversity/introprog-scalalib/releases

ScalaDex: https://index.scala-lang.org/lunduniversity/introprog-scalalib/introprog

Maven Central: https://repo1.maven.org/maven2/se/lth/cs/introprog_3/