V4N4 - Complang

QTF (continued from page 21)
variables. (I used execution variables
just to avoid confusing things).
Using the Commands
To enter the Editor, type the word
n write
where “n” is the number of the block
you want to edit. If there’s anything in
the block already, it will be typed out.
Since our formatter application re-
quires a continuous stream of text
within each block (no embedded car-
riage returns), the Editor decides
where to end each line on the display
- actually, the first occurrence of a
blank after the 55th character on each
line. (Remember, the Editor formats
the contents of the screen differently
than the formatter will display your
text.)
The cursor will appear just after the
last character displayed, or, if the
block is empty, at the home position.
The number of characters in the block
(the current “length”) will appear in
the lower right hand corner.
You can use the cursor movement
keys to position the cursor to any
character that actually exists in the
block. You can move it backwards or
up, but not forward or down (beyond
the “length”), until you enter more
text. If you move the cursor all the way
back to the beginning of a line, it will
then skip up to the end of the next line
above - not to the 79th column, but
to the blank space that follows the last
word on the line. And you can only
move the cursor forward as far as the
last character in each line (the space),
then it will drop to the beginning of
the next line.
While in command mode you can
also get into Enter Mode, Replace
Mode, or Delete Mode by pressing
“e,” “r,” and “d” respectively.
Table 1 shows all the commands that
are available as keystrokes in Com-
mand Mode.
Enter Mode
Press the “e” key while in Com-
mand Mode to begin entering text.
The words “ENTERING MODE” will
appear in the upper right-hand corner.
In this mode, all the alphanumeric
keys on your keyboard will be con-
sidered characters you want to enter,
not commands.
I’ve already discussed the Editor’s
two approaches to the IIO problem in
Enter mode. But with either approach
the Editor’s wrap-around strategy ap-
plies. This means you don’t press
“return” at the end of each line; you
just keep typing and the editor will
worry about line breaks. Press return
only when you want to get back to
Command Mode.
If you make a mistake while in Enter
Mode, press the backspace key. You
can even backspace past the beginning
of a displayed line and up to the end
of the previous line, just like with cur-
sor movements.
In either the Burst or Continuous
versions of Enter Mode, you can
backspace all the way back to the
beginning of the block, thereby
deleting all such text.
As you enter text, make sure the
length in the lower right hand corner
doesn’t exceed 1024, or you’ll lose the
end of your text. I recommend that
you only fill blocks about 2/3 full, to
leave room for later insertions.
Delete Mode
I’ve also covered Delete Mode in
the discussion on the 110 alternatives
earlier. For either version, just “X”
over the string to be deleted. Press-
ing the return key joins the parts
of the text on either side of the de-
letion.
While in Delete Mode, the only valid
keystrokes are “x,” upper case “X” for
fast deletions, backspace and return.
Any other key will emit a beep.
A quick way to clear everything
Table 2 Editor-related FORTH commands
from the cursor to the end of the
screen is the “cntrl-c” key. Since this
is a dangerous command, it requires
holding down the “control” key and
the “c” simultaneously. You can clear
the entire contents of a screen with the
combination “a” “cntrl-c” (the “a” key
homes the cursor to the beginning of
the screen).
Replace Mode
Use this mode when you want to
correct text without moving any text
forward (as in insert) or backward (as
in delete). For example, to change the
word “most” to “many,” simply move
the cursor to the “0,” then enter
Replace Mode by typing “r.” Then
type “any.” Be sure to hit “return”
when you’re done replacing!
The “Take” Command
The ‘It” (for Take) key takes the
string you just “x”ed out, and inserts
it wherever the cursor is now. In com-
bination with “x,” you can use this
command to move any length of text
from one place to another, even from
one block to another. Use it to swap
phrases, sentences, paragraphs, etc.
You can also use “t” if you need
multiple copies of the same string,
without having to retype it each time.
Just “x” out the string, then press “t”
to take it back, then press “t” again to
take a second copy, and again as many
times as you need. This technique
works because “x” saves the text that
you delete in a buffer. The “t” com-
mand copies whatever is in that buf-
fer into your block.
If you need to transfer a LOT of text
from the end of one block to another
block, or even copy an entire block,
re-enters the Editor, using the block most recently displayed
re-enters the Editor, using the next block
re-enters the Editor, using one block back
enters the Editor, displaying your document’s loadblock. When you press
return to exit, Ib returns to the block you were originally editing. You must
first identify your loadblock with the phrase n loadblock ! where “n” is the
number of your loadblock.
FORTH Dimensions 99 Volume IV, No. 4