The mouse pointer manipulating code : <p>Suppose , I am in the year , let's say , in 1950's or 1960's . I don't have much facilities available in the programming languages available to me , like , PASCAL or FORTRAN OR ALGOL, and only recently "computer mouse " has been introduced and invented and only recently they are being supplied along with computer and when attached to one particular port in my computer I can see a "small arrow" on the computer screen (let it be even a CRT screen , hope you would allow relaxation for the lack of synchronization with actual chronology ) moving in accordance with the way I moved the mouse . </p>

<p>Now I wanted to have computer programs that could control the mouse pointer on screen. Let's say I want to write a computer program which would move the mouse pointer in the direction opposite to the direction in which I am moving the mouse or a computer program  to freeze the pointer on the mouse screen for few seconds or a computer program to change the shape of the mouse pointer when the mouse is moved to a specific part of the screen .</p>

<p>Given this requirement how will my language interact with the system to control the mouse pointer . Will the compiler of my language be changed to add few more instructions (or methods or functions ) which will yield machine code controlling the mouse pointers ? </p>
