Epson MX-80 User Manual page 56

Chapter 6
and RUN
CURSES! (the villian said), there's that extra Line Feed again. We overshot the
top of the next form.
Well, it's back to the Printer buttons again. OFF LINE then F F will get us to the
top of the next sheet.
A Little Homespun Philosophy
Having discovered the problem, and it is a very real and vital one, let's analyze the
needs of the average user of the Form Feed (FF) command. Typically, he is a
businessman sending out a long string of bills. Or, perhaps it's an organization
sending out a mess of letters, or printing address labels. In any case, what happens
is repetitive, with perhaps certain places on a pre-printed form being hit by the
Printer to fill in certain information.
This means the Printer runs continuously. The program will certainly not stop
after each form is printed. The program printing all these forms will have the com-
puter in a continuous loop, READing in and processing new information from
Disk, Tape, Data Lines, or even from the keyboard, then printing it in a specific
format on the forms.
Understanding and appreciating that concept is vital to understanding how FF is
used.
Now, if we can delay execution of the extra Line Feeds caused by sending form
control commands, we can effectively forget them. Sort of like taxes. Delay them
long enough and they don't matter.
We learned long ago in our study of Elementary BASIC that a semicolon (;) at the
end of a PRINT line temporarily supresses its Line Feed and Carriage Return. But
when the program comes to its END, the supressed LF/CR catches up. What
would happen if we put our LPRINT CHR$(140) Form Feed command into the
continuous loop with the forms printing statements? You got it!
(NOTE: The supressed LF/CR's don't just keep adding up and dump out at the
END, spilling all over the floor. Only 1 of them can hang over our head, awaiting
disposition.)
CHARGE!
Let's modify our resident program to do it. It requires 2 steps:
40 L P R I N T C H R $ ( 1 4 0 ) ; ' FF CODE 1 2
5 0 GOTO 1 0
5X