<s>
Forth	O
is	O
a	O
procedural	B-Application
,	O
stack-oriented	B-Language
programming	I-Language
language	I-Language
and	O
interactive	O
environment	O
designed	O
by	O
Charles	O
H	O
.	O
"	O
Chuck	O
"	O
Moore	O
and	O
first	O
used	O
by	O
other	O
programmers	O
in	O
1970	O
.	O
</s>
<s>
The	O
FORTH-79	O
and	O
FORTH-83	O
implementations	O
,	O
which	O
were	O
not	O
written	O
by	O
Moore	O
,	O
became	O
de	O
facto	O
standards	O
,	O
and	O
an	O
official	O
standardization	O
of	O
the	O
language	O
was	O
published	O
in	O
1994	O
as	O
ANS	B-Application
Forth	I-Application
.	O
</s>
<s>
A	O
wide	O
range	O
of	O
Forth	O
derivatives	O
existed	O
before	O
and	O
after	O
ANS	B-Application
Forth	I-Application
.	O
</s>
<s>
The	O
free	O
software	O
Gforth	B-Language
implementation	O
is	O
actively	O
maintained	O
,	O
as	O
are	O
several	O
commercially	O
supported	O
systems	O
.	O
</s>
<s>
A	O
stack	B-Application
is	O
used	O
to	O
pass	O
parameters	O
between	O
words	O
,	O
leading	O
to	O
a	O
Reverse	B-Application
Polish	I-Application
Notation	O
style	O
.	O
</s>
<s>
For	O
much	O
of	O
Forth	O
's	O
existence	O
,	O
the	O
standard	O
technique	O
was	O
to	O
compile	O
to	O
threaded	B-Application
code	I-Application
,	O
which	O
can	O
be	O
interpreted	O
faster	O
than	O
bytecode	O
.	O
</s>
<s>
No	O
longer	O
constrained	O
by	O
space	O
,	O
there	O
are	O
modern	O
implementations	O
that	O
generate	O
optimized	B-Application
machine	B-Language
code	I-Language
like	O
other	O
language	O
compilers	O
.	O
</s>
<s>
The	O
relative	O
simplicity	O
of	O
creating	O
a	O
basic	O
Forth	O
system	O
has	O
led	O
to	O
many	O
personal	O
and	O
proprietary	O
variants	O
,	O
such	O
as	O
the	O
custom	O
Forth	O
used	O
to	O
implement	O
the	O
bestselling	O
1986	O
video	O
game	O
Starflight	B-Application
from	O
Electronic	O
Arts	O
.	O
</s>
<s>
Forth	O
is	O
used	O
in	O
the	O
Open	B-Architecture
Firmware	I-Architecture
boot	B-Application
loader	I-Application
,	O
in	O
space	O
applications	O
such	O
as	O
the	O
Philae	O
spacecraft	O
,	O
and	O
in	O
other	O
embedded	B-Architecture
systems	I-Architecture
which	O
involve	O
interaction	O
with	O
hardware	O
.	O
</s>
<s>
Moore	O
later	O
developed	O
a	O
series	O
of	O
microprocessors	O
for	O
executing	O
compiled	O
Forth-like	O
code	O
directly	O
and	O
experimented	O
with	O
smaller	O
languages	O
based	O
on	O
Forth	O
concepts	O
,	O
including	O
cmForth	O
and	O
colorForth	B-Language
.	O
</s>
<s>
Forth	O
has	O
a	O
niche	O
in	O
astronomical	O
and	O
space	O
applications	O
as	O
well	O
as	O
a	O
history	O
in	O
embedded	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
The	O
Open	B-Architecture
Firmware	I-Architecture
boot	B-Operating_System
ROMs	I-Operating_System
used	O
by	O
Apple	O
,	O
IBM	O
,	O
Sun	O
,	O
and	O
OLPC	B-Application
XO-1	I-Application
contain	O
a	O
Forth	O
environment	O
.	O
</s>
<s>
Forth	O
was	O
the	O
first	O
resident	B-Application
software	I-Application
on	O
the	O
new	O
Intel	B-General_Concept
8086	I-General_Concept
chip	O
in	O
1978	O
,	O
and	O
MacFORTH	B-Application
was	O
the	O
first	O
resident	O
development	O
system	O
for	O
the	O
Macintosh	B-Device
128K	I-Device
in	O
1984	O
.	O
</s>
<s>
Atari	O
,	O
Inc	O
.	O
used	O
an	O
elaborate	O
animated	O
demo	O
written	O
in	O
Forth	O
to	O
showcase	O
capabilities	O
of	O
the	O
Atari	B-Device
400	I-Device
and	I-Device
800	I-Device
computers	O
in	O
department	O
stores	O
.	O
</s>
<s>
Three	O
video	O
games	O
from	O
Electronic	O
Arts	O
,	O
published	O
in	O
the	O
1980s	O
,	O
were	O
written	O
in	O
Forth	O
:	O
Worms	B-Application
?	I-Application
</s>
<s>
(	O
1983	O
)	O
,	O
Starflight	B-Application
(	O
1986	O
)	O
,	O
and	O
Lords	B-Application
of	I-Application
Conquest	I-Application
(	O
1986	O
)	O
.	O
</s>
<s>
Robot	O
coding	O
game	O
ChipWits	B-Device
(	O
1984	O
)	O
was	O
written	O
in	O
MacFORTH	B-Application
.	O
</s>
<s>
Ashton-Tate	O
'	O
s	O
RapidFile	O
(	O
1986	O
)	O
,	O
a	O
flat-file	O
database	O
program	O
,	O
and	O
VP-Planner	O
from	O
Paperback	O
Software	O
International	O
(	O
1983	O
)	O
,	O
a	O
spreadsheet	O
program	O
competing	O
with	O
Lotus	B-Application
1-2-3	I-Application
,	O
were	O
written	O
in	O
Forth	O
.	O
</s>
<s>
The	O
Canon	B-Device
Cat	I-Device
(	O
1987	O
)	O
uses	O
Forth	O
for	O
its	O
system	O
programming	O
.	O
</s>
<s>
Rockwell	O
produced	O
single-chip	O
microcomputers	B-Architecture
with	O
resident	O
Forth	O
kernels	O
:	O
the	O
R65F11	O
and	O
R65F12	O
.	O
</s>
<s>
Forth	O
is	O
so-named	O
,	O
because	O
in	O
1968	O
"	O
the	O
file	O
holding	O
the	O
interpreter	O
was	O
labeled	O
FOURTH	O
,	O
for	O
4th	O
(	O
next	O
)	O
generation	O
software	O
,	O
but	O
the	O
IBM	B-Device
1130	I-Device
operating	B-General_Concept
system	I-General_Concept
restricted	O
file	O
names	O
to	O
five	O
characters.	O
"	O
</s>
<s>
FORTH	O
,	O
Inc.	O
'	O
s	O
microFORTH	O
was	O
developed	O
for	O
the	O
Intel	B-General_Concept
8080	I-General_Concept
,	O
Motorola	B-Device
6800	I-Device
,	O
Zilog	B-General_Concept
Z80	I-General_Concept
,	O
and	O
RCA	B-General_Concept
1802	I-General_Concept
microprocessors	O
,	O
starting	O
in	O
1976	O
.	O
</s>
<s>
MicroFORTH	O
was	O
later	O
used	O
by	O
hobbyists	O
to	O
generate	O
Forth	O
systems	O
for	O
other	O
architectures	O
,	O
such	O
as	O
the	O
6502	B-General_Concept
in	O
1978	O
.	O
</s>
<s>
The	O
Forth	B-Application
Interest	I-Application
Group	I-Application
was	O
formed	O
in	O
1978	O
.	O
</s>
<s>
It	O
promoted	O
and	O
distributed	O
its	O
own	O
version	O
of	O
the	O
language	O
,	O
FIG-Forth	B-Application
,	O
for	O
most	O
makes	O
of	O
home	O
computer	O
.	O
</s>
<s>
Forth	O
was	O
popular	O
in	O
the	O
early	O
1980s	O
,	O
because	O
it	O
was	O
well	O
suited	O
to	O
the	O
limited	O
memory	O
of	O
microcomputers	B-Architecture
.	O
</s>
<s>
The	O
British	O
Jupiter	B-Language
ACE	I-Language
home	O
computer	O
has	O
Forth	O
in	O
its	O
ROM-resident	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Words	O
for	O
bigger	O
tasks	O
call	B-Operating_System
upon	O
many	O
smaller	O
words	O
that	O
each	O
accomplish	O
a	O
distinct	O
sub-task	O
.	O
</s>
<s>
These	O
words	O
,	O
being	O
distinct	O
modules	O
that	O
communicate	O
implicitly	O
via	O
a	O
stack	B-Application
mechanism	O
,	O
can	O
be	O
prototyped	O
,	O
built	O
and	O
tested	O
independently	O
.	O
</s>
<s>
Forth	O
has	O
been	O
called	O
a	O
meta-application	O
language	O
:	O
a	O
language	O
that	O
can	O
be	O
used	O
to	O
create	O
problem-oriented	B-Language
languages	I-Language
.	O
</s>
<s>
Forth	O
relies	O
on	O
explicit	O
use	O
of	O
a	O
data	B-Application
stack	I-Application
and	O
reverse	B-Application
Polish	I-Application
notation	O
which	O
is	O
commonly	O
used	O
in	O
calculators	O
from	O
Hewlett-Packard	O
.	O
</s>
<s>
First	O
the	O
numbers	O
25	O
and	O
10	O
are	O
put	O
on	O
the	O
stack	B-Application
.	O
</s>
<s>
The	O
word	O
*	O
takes	O
the	O
top	O
two	O
numbers	O
from	O
the	O
stack	B-Application
,	O
multiplies	O
them	O
,	O
and	O
puts	O
the	O
product	O
back	O
on	O
the	O
stack	B-Application
.	O
</s>
<s>
Then	O
the	O
number	O
50	O
is	O
placed	O
on	O
the	O
stack	B-Application
.	O
</s>
<s>
Even	O
Forth	O
's	O
structural	O
features	O
are	O
stack-based	B-Language
.	O
</s>
<s>
The	O
text	O
in	O
parentheses	O
is	O
a	O
comment	O
,	O
advising	O
that	O
this	O
word	O
expects	O
a	O
number	O
on	O
the	O
stack	B-Application
and	O
will	O
return	O
a	O
possibly	O
changed	O
number	O
(	O
on	O
the	O
stack	B-Application
)	O
.	O
</s>
<s>
The	O
subroutine	O
uses	O
the	O
following	O
commands	O
:	O
DUP	O
duplicates	O
the	O
number	O
on	O
the	O
stack	B-Application
;	O
6	O
pushes	O
a	O
6	O
on	O
top	O
of	O
the	O
stack	B-Application
;	O
<	O
compares	O
the	O
top	O
two	O
numbers	O
on	O
the	O
stack	B-Application
(	O
6	O
and	O
the	O
DUPed	O
input	O
)	O
,	O
and	O
replaces	O
them	O
with	O
a	O
true-or-false	O
value	O
;	O
IF	O
takes	O
a	O
true-or-false	O
value	O
and	O
chooses	O
to	O
execute	O
commands	O
immediately	O
after	O
it	O
or	O
to	O
skip	O
to	O
the	O
ELSE	O
;	O
DROP	O
discards	O
the	O
value	O
on	O
the	O
stack	B-Application
;	O
5	O
pushes	O
a	O
5	O
on	O
top	O
of	O
the	O
stack	B-Application
;	O
and	O
THEN	O
ends	O
the	O
conditional	O
.	O
</s>
<s>
The	O
FLOOR5	O
word	O
is	O
equivalent	O
to	O
this	O
function	O
written	O
in	O
the	O
C	B-Language
programming	I-Language
language	I-Language
using	O
the	O
ternary	O
operator	O
'	O
?	O
</s>
<s>
First	O
a	O
number	O
(	O
1	O
or	O
8	O
)	O
is	O
pushed	O
onto	O
the	O
stack	B-Application
,	O
FLOOR5	O
is	O
called	O
,	O
which	O
pops	O
the	O
number	O
again	O
and	O
pushes	O
the	O
result	O
.	O
</s>
<s>
Finally	O
,	O
a	O
call	B-Operating_System
to	O
.	O
</s>
<s>
The	O
interpreter	O
reads	O
a	O
line	O
of	O
input	O
from	O
the	O
user	O
input	O
device	O
,	O
which	O
is	O
then	O
parsed	O
for	O
a	O
word	O
using	O
spaces	O
as	O
a	O
delimiter	B-Algorithm
;	O
some	O
systems	O
recognise	O
additional	O
whitespace	O
characters	O
.	O
</s>
<s>
If	O
the	O
word	O
is	O
n't	O
found	O
,	O
the	O
word	O
is	O
assumed	O
to	O
be	O
a	O
number	O
and	O
an	O
attempt	O
is	O
made	O
to	O
convert	O
it	O
into	O
a	O
number	O
and	O
push	O
it	O
on	O
the	O
stack	B-Application
;	O
if	O
successful	O
,	O
the	O
interpreter	O
continues	O
parsing	O
the	O
input	O
stream	O
.	O
</s>
<s>
Forth	O
assemblers	O
often	O
use	O
a	O
reverse	B-Application
Polish	I-Application
syntax	O
in	O
which	O
the	O
parameters	O
of	O
an	O
instruction	O
precede	O
the	O
instruction	O
.	O
</s>
<s>
A	O
typical	O
reverse	B-Application
Polish	I-Application
assembler	O
prepares	O
the	O
operands	O
on	O
the	O
stack	B-Application
and	O
the	O
mnemonic	O
copies	O
the	O
whole	O
instruction	O
into	O
memory	O
as	O
the	O
last	O
step	O
.	O
</s>
<s>
"	O
dsp	O
"	O
for	O
the	O
register	O
used	O
as	O
the	O
data	B-Application
stack	I-Application
pointer	O
.	O
</s>
<s>
Most	O
Forth	O
systems	O
run	O
under	O
a	O
host	O
operating	B-General_Concept
system	I-General_Concept
such	O
as	O
Microsoft	B-Application
Windows	I-Application
,	O
Linux	B-Application
or	O
a	O
version	O
of	O
Unix	B-Application
and	O
use	O
the	O
host	O
operating	B-General_Concept
system	I-General_Concept
's	O
file	B-Application
system	I-Application
for	O
source	O
and	O
data	O
files	O
;	O
the	O
ANSI	O
Forth	O
Standard	O
describes	O
the	O
words	O
used	O
for	O
I/O	O
.	O
</s>
<s>
An	O
embedded	B-Architecture
system	I-Architecture
with	O
a	O
resident	O
compiler	O
gets	O
its	O
source	O
via	O
a	O
serial	O
line	O
.	O
</s>
<s>
Classic	O
Forth	O
systems	O
traditionally	O
use	O
neither	O
operating	B-General_Concept
system	I-General_Concept
nor	O
file	B-Application
system	I-Application
.	O
</s>
<s>
Multitasking	B-Operating_System
,	O
most	O
commonly	O
cooperative	O
round-robin	B-Algorithm
scheduling	I-Algorithm
,	O
is	O
normally	O
available	O
(	O
although	O
multitasking	B-Operating_System
words	O
and	O
support	O
are	O
not	O
covered	O
by	O
the	O
ANSI	O
Forth	O
Standard	O
)	O
.	O
</s>
<s>
Each	O
task	O
has	O
its	O
own	O
stacks	B-Application
,	O
private	O
copies	O
of	O
some	O
control	O
variables	O
and	O
a	O
scratch	O
area	O
.	O
</s>
<s>
Swapping	O
tasks	O
is	O
simple	O
and	O
efficient	O
;	O
as	O
a	O
result	O
,	O
Forth	O
multitaskers	O
are	O
available	O
even	O
on	O
very	O
simple	O
microcontrollers	B-Architecture
,	O
such	O
as	O
the	O
Intel	B-Architecture
8051	I-Architecture
,	O
Atmel	B-Architecture
AVR	I-Architecture
,	O
and	O
TI	B-Architecture
MSP430	I-Architecture
.	O
</s>
<s>
Other	O
non-standard	O
facilities	O
include	O
a	O
mechanism	O
for	O
issuing	O
calls	O
to	O
the	O
host	O
OS	O
or	O
windowing	B-Application
systems	I-Application
,	O
and	O
many	O
provide	O
extensions	O
that	O
employ	O
the	O
scheduling	O
provided	O
by	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
A	O
full-featured	O
Forth	O
system	O
with	O
all	O
source	O
code	O
will	O
compile	O
itself	O
,	O
a	O
technique	O
commonly	O
called	O
meta-compilation	B-Application
or	O
self-hosting	O
,	O
by	O
Forth	O
programmers	O
(	O
although	O
the	O
term	O
does	O
n't	O
exactly	O
match	O
meta-compilation	B-Application
as	O
it	O
is	O
normally	O
defined	O
)	O
.	O
</s>
<s>
For	O
embedded	B-Architecture
systems	I-Architecture
,	O
the	O
code	O
may	O
instead	O
be	O
written	O
to	O
another	O
computer	O
,	O
a	O
technique	O
known	O
as	O
cross	B-Application
compilation	I-Application
,	O
over	O
a	O
serial	O
port	O
or	O
even	O
a	O
single	O
TTL	B-General_Concept
bit	O
,	O
while	O
keeping	O
the	O
word	O
names	O
and	O
other	O
non-executing	O
parts	O
of	O
the	O
dictionary	O
in	O
the	O
original	O
compiling	O
computer	O
.	O
</s>
<s>
Often	O
the	O
most	O
time-consuming	O
part	O
of	O
writing	O
a	O
remote	O
port	O
is	O
constructing	O
the	O
initial	O
program	O
to	O
implement	O
fetch	O
,	O
store	O
and	O
execute	O
,	O
but	O
many	O
modern	O
microprocessors	O
have	O
integrated	O
debugging	O
features	O
(	O
such	O
as	O
the	O
Motorola	B-Device
CPU32	I-Device
)	O
that	O
eliminate	O
this	O
task	O
.	O
</s>
<s>
The	O
dictionary	O
is	O
laid	O
out	O
in	O
memory	O
as	O
a	O
tree	O
of	O
linked	B-Data_Structure
lists	I-Data_Structure
with	O
the	O
links	O
proceeding	O
from	O
the	O
latest	O
(	O
most	O
recently	O
)	O
defined	O
word	O
to	O
the	O
oldest	O
,	O
until	O
a	O
sentinel	B-Data_Structure
value	I-Data_Structure
,	O
usually	O
a	O
NULL	O
pointer	O
,	O
is	O
found	O
.	O
</s>
<s>
A	O
linked	B-Data_Structure
list	I-Data_Structure
search	O
continues	O
as	O
the	O
branch	O
merges	O
into	O
the	O
main	O
trunk	O
leading	O
eventually	O
back	O
to	O
the	O
sentinel	O
,	O
the	O
root	O
.	O
</s>
<s>
In	O
rare	O
cases	O
such	O
as	O
meta-compilation	B-Application
a	O
dictionary	O
might	O
be	O
isolated	O
and	O
stand-alone	O
.	O
</s>
<s>
In	O
some	O
environments	O
(	O
such	O
as	O
embedded	B-Architecture
systems	I-Architecture
)	O
the	O
heads	O
occupy	O
memory	O
unnecessarily	O
.	O
</s>
<s>
However	O
,	O
some	O
cross-compilers	B-Application
may	O
put	O
heads	O
in	O
the	O
target	O
if	O
the	O
target	O
itself	O
is	O
expected	O
to	O
support	O
an	O
interactive	O
Forth	O
.	O
</s>
<s>
For	O
instance	O
,	O
IF	O
and	O
WHILE	O
,	O
and	O
the	O
words	O
that	O
match	O
with	O
those	O
,	O
set	O
up	O
BRANCH	O
(	O
unconditional	O
branch	O
)	O
and	O
?	O
BRANCH	O
(	O
pop	O
a	O
value	O
off	O
the	O
stack	B-Application
,	O
and	O
branch	O
if	O
it	O
is	O
false	O
)	O
.	O
</s>
<s>
During	O
compilation	O
,	O
the	O
data	B-Application
stack	I-Application
is	O
used	O
to	O
support	O
control	O
structure	O
balancing	O
,	O
nesting	O
,	O
and	O
back-patching	O
of	O
branch	O
addresses	O
.	O
</s>
<s>
LIT	O
is	O
the	O
primitive	O
word	O
for	O
pushing	O
a	O
"	O
literal	O
"	O
number	O
onto	O
the	O
data	B-Application
stack	I-Application
.	O
</s>
<s>
The	O
interpreter	O
continues	O
to	O
read	O
space-delimited	O
words	O
from	O
the	O
user	O
input	O
device	O
.	O
</s>
<s>
LITERAL	O
has	O
the	O
compilation	O
semantics	O
to	O
take	O
an	O
object	O
from	O
the	O
data	B-Application
stack	I-Application
and	O
to	O
append	O
semantics	O
to	O
the	O
current	O
colon	O
definition	O
to	O
place	O
that	O
object	O
on	O
the	O
data	B-Application
stack	I-Application
.	O
</s>
<s>
In	O
Forth	O
,	O
unnamed	O
words	O
can	O
be	O
defined	O
with	O
the	O
word	O
:NONAME	O
which	O
compiles	O
the	O
following	O
words	O
up	O
to	O
the	O
next	O
;	O
(	O
semi-colon	O
)	O
and	O
leaves	O
an	O
execution	O
token	O
on	O
the	O
data	B-Application
stack	I-Application
.	O
</s>
<s>
The	O
execution	O
token	O
provides	O
an	O
opaque	O
handle	O
for	O
the	O
compiled	O
semantics	O
,	O
similar	O
to	O
the	O
function	B-Language
pointers	I-Language
of	O
the	O
C	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
The	O
word	O
EXECUTE	O
takes	O
an	O
execution	O
token	O
from	O
the	O
data	B-Application
stack	I-Application
and	O
performs	O
the	O
associated	O
semantics	O
.	O
</s>
<s>
The	O
word	O
COMPILE	O
,	O
(	O
compile-comma	O
)	O
takes	O
an	O
execution	O
token	O
from	O
the	O
data	B-Application
stack	I-Application
and	O
appends	O
the	O
associated	O
semantics	O
to	O
the	O
current	O
definition	O
.	O
</s>
<s>
The	O
word	O
'	O
(	O
tick	O
)	O
takes	O
the	O
name	O
of	O
a	O
word	O
as	O
a	O
parameter	O
and	O
returns	O
the	O
execution	O
token	O
associated	O
with	O
that	O
word	O
on	O
the	O
data	B-Application
stack	I-Application
.	O
</s>
<s>
The	O
words	O
:	O
(	O
colon	O
)	O
,	O
POSTPONE	O
,	O
'	O
(	O
tick	O
)	O
are	O
examples	O
of	O
parsing	O
words	O
that	O
take	O
their	O
arguments	O
from	O
the	O
user	O
input	O
device	O
instead	O
of	O
the	O
data	B-Application
stack	I-Application
.	O
</s>
<s>
In	O
most	O
Forth	O
systems	O
,	O
the	O
body	O
of	O
a	O
code	O
definition	O
consists	O
of	O
either	O
machine	B-Language
language	I-Language
,	O
or	O
some	O
form	O
of	O
threaded	B-Application
code	I-Application
.	O
</s>
<s>
The	O
original	O
Forth	O
which	O
follows	O
the	O
informal	O
FIG	O
standard	O
(	O
Forth	B-Application
Interest	I-Application
Group	I-Application
)	O
,	O
is	O
a	O
TIL	O
(	O
Threaded	O
Interpretive	O
Language	O
)	O
.	O
</s>
<s>
The	O
fastest	O
modern	O
Forths	O
,	O
such	O
as	O
SwiftForth	O
,	O
VFX	O
Forth	O
,	O
and	O
iForth	O
,	O
compile	O
Forth	O
to	O
native	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
Instance	O
behavior	O
of	O
a	O
VARIABLE	O
returns	O
its	O
address	O
on	O
the	O
stack	B-Application
.	O
</s>
<s>
The	O
function	O
provided	O
by	O
local	O
variables	O
in	O
other	O
languages	O
is	O
provided	O
by	O
the	O
data	B-Application
stack	I-Application
in	O
Forth	O
(	O
although	O
Forth	O
also	O
has	O
real	O
local	O
variables	O
)	O
.	O
</s>
<s>
(	O
dot-quote	O
)	O
reads	O
a	O
double-quote	O
delimited	B-Algorithm
string	O
and	O
appends	O
code	O
to	O
the	O
current	O
definition	O
so	O
that	O
the	O
parsed	O
string	O
will	O
be	O
displayed	O
on	O
execution	O
.	O
</s>
<s>
(	O
(	O
dot-paren	O
)	O
is	O
an	O
immediate	O
word	O
that	O
parses	O
a	O
parenthesis-delimited	O
string	O
and	O
displays	O
it	O
.	O
</s>
<s>
This	O
definition	O
was	O
written	O
to	O
use	O
the	O
ASCII	B-Protocol
value	I-Protocol
of	O
the	O
Q	O
character	O
(	O
81	O
)	O
directly	O
.	O
</s>
<s>
The	O
word	O
EMIT	O
takes	O
a	O
value	O
from	O
the	O
data	B-Application
stack	I-Application
and	O
displays	O
the	O
corresponding	O
character	O
.	O
</s>
<s>
The	O
following	O
redefinition	O
of	O
EMIT-Q	O
uses	O
the	O
words	O
[	O
(	O
left-bracket	O
)	O
,	O
]	O
(	O
right-bracket	O
)	O
,	O
CHAR	O
and	O
LITERAL	O
to	O
temporarily	O
switch	O
to	O
interpreter	O
state	O
,	O
calculate	O
the	O
ASCII	B-Protocol
value	I-Protocol
of	O
the	O
Q	O
character	O
,	O
return	O
to	O
compilation	O
state	O
and	O
append	O
the	O
calculated	O
value	O
to	O
the	O
current	O
colon	O
definition	O
:	O
</s>
<s>
The	O
parsing	O
word	O
CHAR	O
takes	O
a	O
space-delimited	O
word	O
as	O
parameter	O
and	O
places	O
the	O
value	O
of	O
its	O
first	O
character	O
on	O
the	O
data	B-Application
stack	I-Application
.	O
</s>
<s>
In	O
addition	O
to	O
supporting	O
the	O
standard	O
varieties	O
of	O
desktop	O
computer	O
systems	O
(	O
POSIX	O
,	O
Microsoft	B-Application
Windows	I-Application
,	O
macOS	B-Application
)	O
,	O
many	O
of	O
these	O
Forth	O
systems	O
also	O
target	O
a	O
variety	O
of	O
embedded	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
Swift	O
Forth	O
,	O
machine	B-Language
code	I-Language
generating	O
implementation	O
from	O
Forth	O
,	O
Inc	O
.	O
</s>
