Commodore PET User Manual page 200

to print the asterisks back up over the original three:
vou forgot about the automatic right movement of the PET cursor. Although
the programmed cursor control informs the PET to move the cursor directly up or
directly down. the asterisks will print in a diagonalline due to the cursor's auto-
matic advance. Each time a character is printed. the cursor is automatically ad-
vanced one space to the right to prevent overwriting the next character. The
following diagram shows the cursor movement of the previous program:
* ~j1
1 11
"\
Automatic cursor ad\tance
To print a vertical line. vou must compensate for the automatic advance by
moving the cursor back one space to the left before moving it up or down one
space. For example. the following program statement prints a verticalline of three
asterisks down and then a vertical line of three asterisks back up next to the origi-
nal three.
2(1 PF.: 1 tH"
:~:~:I!.l+.
Nlt.,.,.". ;
If vou attempt to program the IN5ERT/DELETE and the RETURN keys. vou
will encounter some surprising results.
The IN5ERT key is not programmable. although it appears to be. If vou try to
program the IN5ERT key. a"
rn ..
will appear between the two sets of quotes.
But when the statement is executed the PET simply ignores the INSERT character.
The DELETE and RETURN keys remain in immediate mode. Trying to pro-
gram the DELETE character in a PRINT statement will merely erase the previous
character; the RETURN character in a PRINT statement will immediately move the
cursor out of the statement and to the next line.
A word of caution: if vou wish to move the cursor with cursor control
kevs while entering characters between quotes in a PRINT statement, vou
must be sure to first get into immediate mode. If vou remain in program
mode, the cursor editing movements will be included as part of the program
statement. To get out of program mode. type a second set of quotation marks or
press RETURN. Either method will return the PET to immediate mode. allowing
vou to go back and make the necessary corrections.
187