Getting a good look at the directory,

[Whammo]

I always document stuff while it's fresh in my mind.
Forth is just as easy to understand when it's well documented as when it's fresh in your mind.

require io	\ Naturally
0 value scr \ Current screen
0 value max \ Number of screens loaded
$a000 constant target \ Address of screens buffer ( addr to target )

: calc 1000 scr * target + ; \ Calculate address of current screen
: sscr 1024 calc 1000 move ; \ Buffer current screen
: blank 53265 dup c@ 239 and swap c! ; \ Hide screen contorsions and speed up
: unblank 53265 dup c@ 16 or swap c! ;	\ Unhide

: rdir begin \ Call this directly for another look
calc 1024 1000 move scr 48 + 1024 c! \ Quickly load screen and store scr as screen code to header blocks
key case \ Cursor keys up, down to page, space to exit 
17 of scr max <> if scr 1+ to scr \ Cursor down, if not on last screen, scr +1
then endof
145 of scr if scr 1- to scr \ Cursor up, if not on first screen, scr -1
then endof
32 of page 0 to scr exit endof \ Space, init scr, bye-bye
endcase again ; \ Loop forever

: ls
parse-name ?dup if else drop s" $" \ Allow for drive #, wildcards i.e. "ls $0:*=p"
then 0 0 to scr to max \ init scr, max
8 0 open ioabort clrchn \ Secondary address of 0, Directory as prg
8 chkin ioabort chrin chrin 2drop page \ Input from device, loose load address, clr/home
chrin drop blank begin chrin drop \ loose LSB line link, hide, start outer loop, loose MSB line link
chrin chrin 8 lshift + . \ Print blocks
[           w stx, \ This is now compile time. Preserve stack pointer
        $d020 inc, \ Show activity while loading by flashing border color
        $d020 dec, \ Don't do this on each side of chrin, it's displeasing.
here                    \ Current compile address to stack
       $ffcf jsr, \ Chrin
+branch      beq, \ Address of branch offset placeholder to stack
swap    $ffd2 jsr, \ JMP address to top of stack, chrout
              jmp, \ I could have BNE'd but compile JMP address on stack
:+                         \ Current address is previous branch offset target
            w ldx, \ Restore stack pointer, back to run-time
]
$d6 c@ $18 = if sscr \ Fetch current line number, if last line, save screen 
scr 1+ to scr page \ Increment screen, clr/home
target 1024 40 move then \ Header on top of every page
cr chrin 0= until clrchn 8 close \ Line 2, loose LSB line link, loop until EOF, input from keys, 
sscr scr to max \ Buffer last screen, set screen limit
0 to scr unblank rdir ; \ Init scr, unhide, call user interface

[jkotlinski]

Nice! For the imaginary tiny text editor, I should maybe consider adding shadow blocks :-)
That seems like a very high quality Forth tradition.

[Whammo]

Hmmmm... Cross linking a line of code with it's comments. Genius!

[jkotlinski]

I think Elizabeth Rather once wrote in the Forth newsgroup. For small systems, they used to have two disks. One disk with code, another with comments, that matched each other block-by-block. To switch between comments and code, press a key that added the right block offset to get to the other disk.

[Whammo]

Fast compiling.

require io
0 value scr
0 value max
$a000 constant target

: calc 1000 scr * target + ;
: sscr 1024 calc 1000 move ;
: blank 53265 dup c@ 239 and swap c! ;
: unblank 53265 dup c@ 16 or swap c! ;

: rdir begin
calc 1024 1000 move scr 48 + 1024 c!
key case 
17 of scr max <> if scr 1+ to scr
then endof
145 of scr if scr 1- to scr
then endof
32 of page 0 to scr exit endof
endcase again ;

: ls
parse-name ?dup if else drop s" $"
then 0 0 to scr to max
8 0 open ioabort clrchn
8 chkin ioabort chrin chrin 2drop page
chrin drop blank begin chrin drop
chrin chrin 8 lshift + .
[ w stx, $d020 inc, $d020 dec, here
$ffcf jsr, +branch beq, swap
$ffd2 jsr, jmp, :+ w ldx, ]
$d6 c@ $18 = if sscr 
scr 1+ to scr page
target 1024 40 move then
cr chrin 0= until clrchn 8 close 
sscr scr to max
0 to scr unblank rdir ;