5 - Forth Interest Group
5 - Forth Interest Group
5 - Forth Interest Group
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If CHR is a period then set DPL to<br />
zero and leave true flag else leave<br />
false flag.<br />
?ASCII flag --- flag<br />
If CHR equals character following<br />
?ASCII then leave true flag else<br />
leave false flat.<br />
?BOTH flag --- flag<br />
If flag is true and CHR is a blank<br />
then leave a true flag else leave<br />
a false flag.<br />
?END flag --- flag<br />
If CHR is a blank then leave a true<br />
flag else leave a false flag.<br />
?SIGN false d flag --- sign d flag<br />
If CHR equals - change false flag<br />
to a true flag and leave true flag<br />
on top else leave false flag on<br />
top.<br />
?SKIP flag --- flag<br />
Make flag true. Used to skip past<br />
character if flag was false.<br />
ASCII -- char<br />
Place following character on data<br />
stack a8 a number.<br />
CHR flag -- char<br />
Add flag to >CHR and fetch char-<br />
acter at >CHR to data stack.<br />
N: A definining word used in the<br />
form :<br />
Page 130<br />
N: . . . ;<br />
--- d true<br />
--- false<br />
Convert word at here leaving double<br />
number and a true flag on the data<br />
stack. If word does not convert<br />
leave only a false flag on the data<br />
stack.<br />
N dl flag --- d2 flag<br />
Convert digit at CHR into doriblt<br />
number beneath. If successful<br />
leave true flag else a false flag.<br />
NNN dl flag --- d2 flag<br />
Do three N leaving true flag if<br />
successful else false flag.<br />
NS dl flag --- d2 flag<br />
Do N until failure, leaving a true<br />
flag on top of data stack with >CHR<br />
pointing to last character accepted<br />
(N) dl digit --- d2<br />
Convert binary digit into number<br />
be nea t h .<br />
REQUIRED flag --- flag<br />
TRAIT<br />
If flag is false exit this word<br />
leaving false flag. If flag is<br />
true leave true flag and continue.<br />
---<br />
addr<br />
A variable containing the word<br />
count from the last UNTIL: defined<br />
word.<br />
UNTIL :<br />
A defining word used in the form:<br />
UNTIL: . . . ;<br />
Words created by UNTIL: are like<br />
colon-definitions except the run<br />
time function is to execute words<br />
in the definition until there is a<br />
true flag on the data stack, then<br />
exit the word leaving the word<br />
count of the words executed in the<br />
variable TRAIT.<br />
FORTH DIMENSIONS 11/ 5
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