PGMTIP.015  by James A. McGreevy  70206,1115

Public Domain

Just found a trick with the M100 function keys which might prove useful.  For
quite some time when programming I've been reserving line 65529 for reversing
any Escape codes (which you can't use directly in an Fkey) which may be set
when I hit SHIFT/BREAK, such as

  65529 PRINTCHR$(27)"q"CHR$(27)"Q"CHR$(27)"W":CLS

[ CHR$(27)"q" turns off the reverse mode set by PRINTing CHR$(27)"p",
CHR$(27)"Q" turns off the visible blinking cursor set by CHR$(27)"P", and
CHR$(27)"W" unlocks the screen which is locked - to preserve graphic displays -
with CHR$(27)"V".  See CTRESC.100 or ESCAPE.TXT in DL8 for further info on
Escape codes. ]

I then set Function Key 7 as follows:

  KEY7,"goto65529"+CHR$(13)

Playing around, I tried putting the ENTER in mid-line:

  KEY7,"goto65529"+CHR$(13)+"list

and it worked!  Returns just like a GOSUB.  I can then enter the lines I'm
interested in and press ENTER.  Saves some time when debugging or trying
variations.  You could just as easily use

  KEY7,"goto65529"+CHR$(13)+"?a;b"+CHR$(13)

so that variables you're following will be immediately printed; or

  KEY7,"goto65529"+CHR$(13)+"edit

and enter the lines you wish to edit.  [ When you Edit some lines, the Escape
codes are reset upon leaving Edit; but you will find your M100 behaving
strangely (akin to low-battery behavior) during Editing if you don't first
"normalize" the escape codes, especially with very long programs. ]

You can use up to 15 characters in a function key definition, with characters
such as "?" (for PRINT) or CHR$(13) (for ENTER) counting as one character.
The only reason I use line 65529 is because that is the highest possible line
number and when I'm writing programs I leave gaps of several hundred line
numbers between lines to allow me to re-arrange the order of the program
easily.  Any line number can be used, for instance 999 (to save 2 bytes in the
Fkey definition).

Budding programming geniuses out there might even find that you can define the
function keys within a program in this manner to do all sorts of odd tricks!
But if you do and your program's for public consumption, PLEASE program the
Fkeys back to their normal functions as part of your exit routine.  In most
applications ONKEYGOSUB would be preferable, as that doesn't disrupt the manner
in which the computer owner has defined his Fkeys.

The main utility of the technique detailed above is for use during programming
and debugging.  You could define your function keys as part of the
initialization routine of your program-to-be and UN-define them as part of your
exit routine.  In this way you can individualize the Fkeys for each program
you're writing.  When the program's completed they can be removed.


--jam