EasyConsole

EasyConsole is a library to make it easier for developers to build a simple menu interface for a Delphi console application.

Credit

The basic idea behind this library goes to splttingatms and his EasyConsole build in c# This project is a Delphi remake, and further development, of his idea.

Dependencies

EasyConsole make use of my own Console library DelphiConsole. When using this library. Please make sure you got the newest version of DelphiConsole also.

Features

• Automatically numbered menus
• Easy creation of menus
• Input/Output helpers

Quick Start

Menu

The base functionality of the library is to provide an easy way to create console menus. A Menu consists of Options that will be presented to a user for selection. An option contains a name, that will be displayed to the user, and a callback function to invoke if the user selects the option. Render the menu in the console using the Display() method.

uses
  System.Console,
  EasyConsole.Types;
begin
  with TMenu.Create do
    try
      Add('foo',
        procedure
        begin
          Console.WriteLine('foo selected')
        end);

      Add('bar',
        procedure
        begin
          Console.WriteLine('bar selected')
        end);

      Display;
    finally
      free;
    end;
end.

Utilities - Input/Output

EasyConsole also provides input and output utilities to abstract the concept of dealing with the Console.

The Output class adds helper methods to control the color of text in the console.

uses
  System.Console,
  EasyConsole.Output;
begin
   Output.WriteLine('default');
   Output.WriteLine(TConsoleColor.Red, 'Red');
   Output.WriteLine(TConsoleColor.Green, 'Green');
   Output.WriteLine(TConsoleColor.Blue, 'Blue');
   Console.ReadLine;
end.

The Input class adds helper methods that prompt the user for input. The utility takes care of displaying prompt text and handling parsing logic. For example, non-numeric input will be rejected by ReadInt() and the user will be re-prompted.

uses
  System.Console,
  EasyConsole.Input,
  EasyConsole.Output;
var
  s : String;
  i : Integer;
begin
  s := Input.ReadString('Please enter a string: ');
  Output.WriteLine(  'You wrote: {0}', [s]);

  i := Input.ReadInt('Please enter an integer(between 1 and 10): ', 1, 10);
  Output.WriteLine('You wrote: {0}', [i]);

  Console.ReadLine;
end.

Program

All of these features can be put together to create complex programs with nested menus. A console program consists of a main Program class that contains Pages. The Program class is a navigator of pages and will keep a history of pages that a user is navigating through. Think of it as your browser history. To create a program you must subclass the Program class and add any Pages in the constructor. Note: Before exiting the constructor, you must set one of the pages as the main page where the program should start.

unit DemoProgramU;

interface

uses
  EasyConsole.Types;

type
  TDemoProgram = class(TProgram)
  protected
    constructor Create;
  public
    class procedure CreateAndRun;
  end;

implementation

uses
  DemoPagesU;

{ TDemoProgram }

constructor TDemoProgram.Create;
begin
  inherited Create('EasyConsole Demo', True);
end;

class procedure TDemoProgram.CreateAndRun;
begin
  with TDemoProgram.Create do
    try
      AddPage<TMainPage>;
      AddPage<TPage1>;
      AddPage<TPage1A>;
      AddPage<TPage1AI>;
      AddPage<TPage1B>;
      AddPage<TPage2>;
      AddPage<TInputPage>;
      SetPage<TMainPage>;
      Run;
    finally
      Free;
    end;
end;

end.

A Page can display any type of data, but the subclass MenuPage was created to speed up the creation of pages that display menus. Simply pass in all of the options you want displayed into the options parameter in the constructor.

  TMainPage = class(TMenuPage)
  public
    constructor Create;
    procedure Display; override;
  end;

...

{ TMainPage }

constructor TMainPage.Create;
begin
  inherited Create('Main Page', [TOption.CreateNavigation<TPage1>('Page 1'), TOption.CreateNavigation<TPage2>('Page 2'), TOption.CreateNavigation<TInputPage>('Input')

    , TOption.Create('Exit',
    procedure
    begin
      Halt;
    end)

    ]);
end;

procedure TMainPage.Display;
begin
  Console.Clear;
  inherited;
end;

As you can see, navigation is handled by the Program class. As you navigate through to different pages, the history is logged. You can then invoke NavigateBack() if you would like to go back to the previous page.

Example Project

The source code contains an example console demo under the Demo directory. It offers a demo with nested menu options as well as an example of how to prompt the user for input.