Doctor Knowall Remembers…

The other day, I was caught short for something to read while trying to beat my Rubics cube record of 45 minutes. So, while manipulating my cube with the right hand, I picked up the nearest thing handy… Can you guess what it was ? No, it was the Basic manual. I was suprised to find that basic provides no less than 18 error messages. Of course, I had no seen any of these in years, but I was suprised to find a function that I had almost forgotten about! For some reason, I couldn’t remember ever using it – and I doubt if anyone else has ever used POS either.

POS() returns the ‘x’ position of the printhead and because printers don’t usually backspace or have full cursor movement, POS() will not necessarily return an ‘x’ value corresponding to the cursor position on the screen. Cursor and printhead are independent creatures. This can cause problems if POS() is used in input routines, but POS can be useful in output routines:

Run it, break when you have a screenful of data and enter each DATA line displayed. Run it again if there is more data to follow. Don’t anyone mention USR!

Doctor Knowall’s Definitive Guide to INKEY$ without USRs.

USRs are people who run versions of Pascal written in Forth, which in turn are written in Basic! In short, USRs don’t like Basic. For the benefit of purists struggling along without an INKEY$ function, T plunge into the depths of my immense pool of knowledge … and find not one, but two ways of detecting single key presses from Basic.

The Quick and VERY Simple way –

If you don’t mind using a limited range of keys, the keyboard can be read directly from port 0 using the INP() function. Because of timing, only the first row of keys can be read this way. The following program shows which keys are used and the bits that are assigned to then.