PreTeXt Sample Book Abstract Algebra (SAMPLE ONLY)

<section xml:id="inactive-code">

  <title>Programs</title>

  <p>
    First, some samples of programs that are not interactive.
    They will be syntax highlighted if a valid <attr>language</attr> is specified.
    Optionally, lines can be numbered and selected lines highlighted.
  </p>

  <!-- This example also appears in the PreTeXt Guide (doc/guide/author/topics.xml).  Apply any edit to both copies. -->

  <listing>

    <title>A static Java program with highlighted lines</title>

    <program language="java" line-numbers="yes" highlight-lines="2,6-8">

      <code>
              import javax.swing.JFrame;  //Importing class JFrame
              import javax.swing.JLabel;  //Importing class JLabel
              public class HelloWorld {
                  public static void main(String[] args) {
                      JFrame frame = new JFrame();           //Creating frame
                      frame.setTitle("Hi!");                 //Setting title frame
                      frame.add(new JLabel("Hello, world!"));//Adding text to frame
                      frame.pack();                          //Setting size to smallest
                      frame.setLocationRelativeTo(null);     //Centering frame
                      frame.setVisible(true);                //Showing frame
                  }
              }
      </code>

    </program>

  </listing>

  <p>
    Instead of specifying <attr>language</attr> on each program, a default can be specified at <c>docinfo/programs/@language</c>.
    That value will be used for any program that lacks a <attr>language</attr> attribute.
    This sample does not specify it's own <attr>language</attr> and is relying on the default set in this book.
  </p>

  <listing>

    <title>Python program, relying on default programs language</title>

    <program line-numbers="yes">

      <code>
              def say_hello():
                  print("Hello, World!")
              say_hello()
      </code>

    </program>

  </listing>

</section>