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1. Visual prolog learn pdf how to#
2. Visual prolog learn pdf software#
3. Visual prolog learn pdf code#
4. Visual prolog learn pdf series#
5. Visual prolog learn pdf windows#

The information from such input devices (click of a mouse and other such GUI activity) is known as an event. In a GUI program, all the GUI components wait for inputs from the keyboard and/or mouse (and/or other pointing devices such as digitizer puck, etc.). Hence the programmer has to carefully isolate the logic so that it remains valid irrespective of how the GUI was used, and carefully accommodate those situations, where the program's logic may be unable to accommodate (using polite, easy to understand warning dialogs, etc.). Also, sometimes it would be difficult to predict the consequences that may follow due to some GUI event being triggered.

Visual prolog learn pdf how to#

On one hand, the programming is easier because there is no rigidity or regimentation in the activities of the program that will be carried out.īut on the other hand, the programmer needs to know how each of the GUI components works, what are conventionally accepted practices and how to adhere to those practices so that the user is not given unnecessary surprises when using the program.

Visual prolog learn pdf software#

In fact, one of the common methods by which people get to grips with a piece of software is by such casual browsing over the GUI of a program.Īnyway, to cut a long story short the programmer has to use a different strategy when programming GUI programs. You can take the mouse cursor through each one of them without really being compelled to click on any of the menu item you may find there. Consider this scenario: The File menu will have several menu items. You can laze around casually flipping through the menus without really clicking on any of them.

Visual prolog learn pdf windows#

For example if you start any conventional Windows program, it normally will not press you to do this or do that. The user can be given options what should be done on which part of the program. With GUI programs, the programmer can choose to be flexible.

Visual prolog learn pdf series#

In a console program, the program is started from the Goal procedure and it is then worked logically from that point onwards, straitjacketing the user through a series of logical steps set out by the programmer. The sequence and direction of activities in the program would have to be determined by the programmer. Console programs do not show graphical elements, so they have the user input either from start-up parameters or from direct questions setup by the programmer in advance. Though both console programs and GUI programs always starts at a fixed entry point (from the Goal procedure), that is where the similarity ends. There is a lot of difference between a GUI and console programs. We will be using the logic of the family example that was tackled in a previous tutorial. In this tutorial we shall set out to do just that. It has given an API (Application Programming Interface) which can be used to setup the GUI required for any program.įurthermore, Visual Prolog has added one more layer - the PFC (Prolog Foundation Classes) to help out not only with the GUI but with other areas of programming too.Īnd even more the Visual Prolog IDE can be used to visually create the mock-ups of the final GUI that would be used by the program that you would be developing. As a programmer one need not get down on our knees to program such graphic, mouse and keyboard functions. Mercifully, both these detailed programming are done by the operating system. It also controls the behaviour of the mouse and other input devices over these graphical areas. the little square with an X on it on the top right corner of a window). It uses complex graphical routines to put (and restore) graphical images on the relevant parts of the computer monitor. In programming terms, a GUI does two things. Each of those elements is known as a GUI component, and in well designed programs, these components work as per conventionally accepted norms. In the Windows operating system environment the term represents the familiar windows with the menu bar, toolbar, the little buttons on the top right hand corner of a window, etc.

Visual prolog learn pdf code#

7 Getting the Main Code into the Program.