1 - Forth Interest Group

Get It Up
I
( Six One-Liners )
( All definitions are in Standard Forth CORE and CORE-EXT words. )
: ANEW >IN @ BL WORD FIND IF EXECUTE ELSE DROP THEN >IN ! MARKER ;
: BOUNDS OVER + SWAP ; ( a n -- a+n a )
: HAVING BL WORD FIND NIP O= IF POSTPONE \ THEN ; IMMEDIATE
: LACKING BL WORD FIND NIP IF POSTPONE \ THEN ; IMMEDIATE
.. S" ANEW NONCE : NONCE-DEF " EVALUATE ; IMMEDIATE
. ..
. t r S" ; NONCE-DEF NONCE " EVALUATE ; IMMEDIATE
0 [ IF] COMMENT
ANEW ( "name" -- )
: ANEW ( "nameW -- )
>IN @
( >in)
BL WORD FIND IF ( . exec-token)
EXECUTE
( >in)
ELSE DROP THEN
>IN ! ( 1
MARKER
If name is found, ANEW executes it. name is expected to
have been defined by MARKER. name will forget itself and all
definitions after it.
ANEW then executes: MARKER name.
This defines name again so you can redefine the definitions
following it.
Put ANEW marker-name at the beginning of your source
files.
BOUNDS ( a n -- a+n a )
: BOUNDS OVER + SWAP ; ( a n -- a+n a )
Note that [ IF] [ ELSE] [ THEN] should be kept balanced
or, better, not used between [ IF] and [ THEN] . This restriction
applies within comments and quoted strings as well.
My personal convention is to use 0 [ IF1 or 1 [ IF] to
select alternative code that should work, FALSE [ I FI to comment
out code that doesn't work, and 0 [ IF] COMMENT to
comment out non-code.
I use \ to comment out code temporarily, and for other
comments I don't want in the final source. That's why you
don't see it much in my code.
I use ( for stack state and other comments I want to keep
in the final source.
Adjust the arguments for a DO-loop. HAVING ( "namel' -- )
0 [ IF] COMMENT
Comment out documentationusing[ IF] [ ELSE] [ THEN] .
Used:
0 [ IF] COMMENT
mumble mumble mumble
[ THEN]
: HAVING ( "name" -- )
BL WORD FIND NIP O=
IF POSTPONE \ THEN
; IMMEDIATE
If name is found, interpret the rest of the line; otherwise,
skip the line. This is IMMEDIATE and can be used in a
definition.
26 Forth Dimensions XlWl