1 - Forth Interest Group

To include more than one line when name is not found:
HAVING name 0 [ IF]
- whatever-
[ THEN]
LACKING ( " name" -- )
: LACKING ( "name" -- )
BL WORD FIND NIP
IF POSTPONE \ THEN
; IMMEDIATE
If name is not found, interpret the rest of the line; otherwise,
skip the line. This is IMMEDIATE and can be used in a
definition.
LACKING is generally used before defining the name that
is lacking.
Start compiling a nonce word. The same as:
Used extensively for data initialization and testing.
Use ; ; to complete the definition, execute it, and forget it.
Nonce words let you execute loops from the keyboard.
They also allow you to initialize data structures programmatically
with no overhead.
Nonce words wouldn't be needed with self-compiling:
IF BEGIN DO DO
From the Random House Dictionary:
nonce word, a word coined and used only for the particular
occasion.
Finish compiling a nonce word, execute it, and forget it. If
errors occur, start over or type NONCE to recover. The same as
Procedarnus in pace.
Wil Baden
; NONCE-DEF NONCE
ANEW NONCE : NONCE-DEF / [ THEN] [ THEN] [ THEN]
Continued from page 29
24 [ ELSE]
2 6 CREATE upper-case-map 256 CHARS ALLOT
28 ( Initialize the map to change characters into themselves. )
29 :: 256 0 DO I upper-case-map I CHARS + C! LOOP ;;
31 ( Replace the lower-case letters with upper-case. )
32 :: [CHAR] a 26 BOUNDS DO
33 I BL XOR upper-case-map I CHARS + C! LOOP
34 ..
I I
3 6 ( Convert to upper-case by 'addr + C@ ' inline. )
3 7 : UP-CHAR S" CHARS upper-case-map + C@ " EVALUATE ; IMMEDIATE
39 : DOWN-CHAR BL XOR UP-CHAR BL XOR ;
41 [ THEN] [ THEN] -
43 ( Convert string to upper-case. )
44 : UP-STRING ( a u - - )
4 5 0 DO DUP C@ UP-CHAR OVER C! CHAR+ LOOP DROP
46 ;
48 SEE UP-STRING CR
Neil Bawd
Goat Hill, California
"Anywhere is interesting for 15 minutes, except maybe Iowa."
Forth Dimensions XlWl 27