How to learn FreePascal

The Pascal programming language has a long history, and much of the online documentation is geared towards beginners. Most of these tutorials deal with console programs, where you print information to the screen and/or read user input. For example, one of the most common beginner tutorial is a program to print 'Hello World' on the screen:

program HelloWorld;
begin
  writeln('Hello World!');
end.

When executed, from a console/terminal, this program will print 'Hello World' on the screen.

Here at Exercism, we use automated testing to ensure your solutions are correct, and therefore we need to use a unit instead of a program. The main difference is that you'll need to return a value from a function instead of print something to terminal:

writeln('Hello World!');

became

result := 'Hello World!'

The write/writeln commands are still useful for displaying information or obtaining a textual representation of the output of a command, a mathematical operation, etc.