Getting Started

Some Simple Programs!

do_nothing.adb

• The shortest Java program: DoNothing.java

   public class DoNothing{
      public static void main(String[] args){;}
   }
   

• The shortest Ada program: do_nothing.adb

   -- The shortest Ada program
   procedure do_nothing is
   begin
      null;   -- Does nothing
   end do_nothing;
   -- Well, is there a shorter Ada program?
   

• Comments: -- to end of line, no multiline comments


• a procedure is similar to a method
• filename (do_nothing.adb) matches procedure name (do_nothing)
• adb means ADa Body
• Case: Ada is not case sensitive, but OS is (use lower case file name)


• procedure do_nothing is like public static void main
• Execution begins at ... begin
• No class needed - do_nothing is a top-level procedure, it's not contained in anything
• do_nothing - you choose identifier for procedure name
• identifier: Letter followed by 0 or more letters, digits, underscores. Underscore followed by letter or digit


• No braces: begin/end instead
• end do_nothing - procedure name repeated (optional, but a good idea)
• Statements followed by semicolons: where are the statements?


• Command line compile and run:

   gnatmake do_nothing
   ./do_nothing        [or just do_nothing]
   

hello.adb

• File hello.adb

   -- This program actually does something
   with Ada.Text_IO; use Ada.Text_IO;
   procedure hello is
   begin
      new_line;
      put_line("Hi!");
      new_line(2);
      put("Welcome to");
      put_line(" ITEC 320!");
   end hello;
   

• With and Use - similar to import (later we will see some differences!)
• Ada.Text_IO - library for I/O of text - similar to System.out
• Statements followed by semicolons: where are statements?


• filename (hello.adb) matches procedure name (hello)


• new_line and new_line(2)
• put and put_line - similar to print and println
• Strings in quotes


• Command line compile and run:

   gnatmake hello
   ./hello         [or just hello]
   

Development Environments

Command Line

• Command line: Editor, gnatmake, run
• Command line environments: Windows cmd window, Mac and Linux terminal, putty connection to rucs


• Editor: vim or pico or ...


• gnatmake foo.adb # gnatmake must be on path


• ./foo [ run executable foo or foo.exe] [may not need ./]

AdaGIDE

• Relatively easy IDE

GPS

• Full-featured IDE


• Requires a project file
• Either create a project file with wizard
• Or write your own (using editor such as vi or pico or notepad++) :

      -- File foo.gpr
      project foo is
         for main use ("foo.adb");
      end foo;
      

• A better project file - include a directory for object files that you don't want to see:
• Either Add the object directory using project/properties
• Or, edit the project file yourself:

      -- File foo.gpr
      project foo is
         for main use ("foo.adb");
         for object_dir use "obj";
      end foo;
      

• You must create directory obj as a child of the directory that contains the .adb and .gpr files
• Click on project file to start GPS
• Project/Properties/main must specify a main program
• Can change main with Project options
• Or simply edit project file with an editor

Other Options

• Other options:
• TextMate
• jGrasp
• Eclipse: plugin available from libre.adacore.com (status is unclear)
• IntelliJ: plugin also available (untested and minimal, but intellij is a nice system)
• Visual Studio Code - Ada plugin not available as far as I know


• Some people combine options (ie edit with IDE and compile and/or run with command line)

More Detail

• More detailed instructions compilation and running are on this page

Installation on Personal Machines

Personal Machine Installation

• Required: gnat. Easiest from: www.adacore.com/community
• A Windows installer is available on the Download page
• If given the opportunity, select the option to add to path


• For other platforms, click the link for "More packages ..."
• Instructions for Mac and Linux:
• Follow instructions here (2017 version not tested)


• GPS: Installing gnat also installs GPS


• AdaGIDE - For those who want it:
• Must install gnat first

More Detail

• More detailed instructions on installing compilers and IDEs are on this page