<s>
VisualWorks	B-Application
(	O
formerly	O
ObjectWorks	O
,	O
afterward	O
Cincom	B-Application
Smalltalk	B-Application
)	O
is	O
a	O
cross-platform	B-Operating_System
implementation	O
of	O
the	O
Smalltalk	B-Application
language	O
.	O
</s>
<s>
It	O
is	O
implemented	O
as	O
a	O
development	O
system	O
based	O
on	O
images	O
,	O
which	O
are	O
dynamic	O
collections	O
of	O
software	O
objects	O
,	O
each	O
contained	O
in	O
a	O
system	B-Operating_System
image	I-Operating_System
.	O
</s>
<s>
The	O
lineage	O
of	O
VisualWorks	B-Application
goes	O
back	O
to	O
the	O
first	O
Smalltalk-80	B-Application
implementation	O
by	O
Xerox	O
PARC	O
.	O
</s>
<s>
In	O
the	O
late	O
1980s	O
,	O
a	O
group	O
of	O
Smalltalk-80	B-Application
developers	O
spun	O
off	O
ParcPlace	O
Systems	O
to	O
further	O
develop	O
Smalltalk-80	B-Application
as	O
a	O
commercial	O
product	O
.	O
</s>
<s>
The	O
commercial	O
product	O
was	O
initially	O
named	O
ObjectWorks	O
,	O
and	O
then	O
VisualWorks	B-Application
.	O
</s>
<s>
On	O
August	O
31	O
,	O
1999	O
,	O
the	O
VisualWorks	B-Application
product	O
was	O
sold	O
to	O
Cincom	B-Application
Systems	I-Application
.	O
</s>
<s>
VisualWorks	B-Application
runs	O
under	O
many	O
operating	O
systems	O
,	O
including	O
Windows	B-Application
,	O
macOS	B-Application
,	O
Linux	B-Application
,	O
and	O
several	O
Unix	B-Application
versions	O
.	O
</s>
<s>
VisualWorks	B-Application
supports	O
cross-platform	B-Operating_System
development	O
projects	O
,	O
because	O
of	O
its	O
built-in	O
multi-platform	B-Operating_System
features	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
application	O
needs	O
to	O
be	O
developed	O
only	O
once	O
,	O
and	O
can	O
then	O
be	O
switched	O
to	O
different	O
widget	O
styles	O
.	O
</s>
<s>
A	O
VisualWorks	B-Application
application	O
can	O
be	O
run	O
on	O
all	O
supported	O
platforms	O
with	O
no	O
modifications	O
.	O
</s>
<s>
Only	O
the	O
virtual	B-Architecture
machine	I-Architecture
is	O
platform-dependent	O
.	O
</s>
<s>
VisualWorks	B-Application
allows	O
for	O
very	O
fast	O
application	O
development	O
,	O
as	O
individual	O
methods	B-Language
can	O
be	O
compiled	O
even	O
while	O
the	O
program	O
to	O
be	O
developed	O
is	O
running	O
.	O
</s>
<s>
Compiling	O
a	O
Smalltalk	B-Application
method	B-Language
typically	O
takes	O
significantly	O
less	O
than	O
a	O
second	O
,	O
while	O
doing	O
the	O
same	O
for	O
a	O
C++	B-Language
project	O
often	O
takes	O
a	O
minute	O
or	O
more	O
,	O
and	O
cannot	O
be	O
done	O
easily	O
without	O
restarting	O
the	O
process	O
.	O
</s>
<s>
The	O
various	O
code	O
browsers	O
of	O
VisualWorks	B-Application
help	O
the	O
developer	O
to	O
quickly	O
locate	O
a	O
class	B-Application
or	O
method	B-Language
of	O
interest	O
.	O
</s>
<s>
The	O
performance	O
and	O
throughput	O
of	O
Smalltalk	B-Application
programs	O
can	O
approach	O
the	O
performance	O
of	O
static	O
languages	O
such	O
as	O
C++	B-Language
,	O
Fortran	B-Application
,	O
Pascal	B-Application
,	O
or	O
Ada	B-Language
using	O
a	O
just-in-time	O
compiler	O
by	O
generating	O
machine	O
code	O
that	O
is	O
specialised	O
for	O
frequently	O
used	O
types	O
,	O
but	O
numeric	O
processing	O
and	O
programs	O
that	O
benefit	O
from	O
precise	O
memory	O
layout	O
may	O
still	O
run	O
slower	O
.	O
</s>
<s>
The	O
generational	O
garbage	B-General_Concept
collector	I-General_Concept
minimises	O
most	O
collection	O
pauses	O
,	O
but	O
may	O
not	O
be	O
suitable	O
for	O
hard	O
real-time	O
and	O
determinism	O
requirements	O
,	O
as	O
long	O
full	O
collections	O
may	O
occur	O
,	O
which	O
may	O
stop	O
the	O
world	O
for	O
tens	O
to	O
hundreds	O
of	O
milliseconds	O
,	O
proportional	O
to	O
heap	O
size	O
.	O
</s>
<s>
However	O
,	O
garbage	B-General_Concept
collection	I-General_Concept
is	O
preferable	O
over	O
manual	O
memory	O
management	O
in	O
an	O
object-oriented	B-Language
language	I-Language
,	O
and	O
the	O
programmer	O
can	O
take	O
various	O
actions	O
to	O
control	O
when	O
and	O
for	O
how	O
long	O
garbage	B-General_Concept
collection	I-General_Concept
occurs	O
;	O
so	O
under	O
most	O
circumstances	O
,	O
garbage	B-General_Concept
collection	I-General_Concept
is	O
not	O
a	O
concern	O
.	O
</s>
<s>
All	O
components	O
of	O
the	O
VisualWorks	B-Application
system	O
are	O
installed	O
on	O
Windows	B-Application
7	O
or	O
later	O
in	O
a	O
Program	O
Files	B-Operating_System
\Cincom	O
directory	B-Application
named	O
after	O
the	O
version	O
number	O
of	O
the	O
installed	O
system	O
–	O
for	O
instance	O
,	O
vw7.5nc	O
.	O
</s>
<s>
This	O
directory	B-Application
contains	O
several	O
subdirectories	B-Application
including	O
bin	O
,	O
doc	O
,	O
examples	O
and	O
many	O
others	O
.	O
</s>
<s>
VisualWorks	B-Application
assumes	O
a	O
three-button	O
mouse	O
with	O
buttons	O
having	O
logical	O
names	O
<Select>, <Operate>, and <Window>	O
.	O
</s>
<s>
Although	O
,	O
a	O
one	O
or	O
two	O
button	O
mouse	O
can	O
be	O
used	O
along	O
with	O
Ctrl	B-Device
,	O
Option	B-Device
,	O
or	O
Command	B-Device
keys	I-Device
.	O
</s>
<s>
<Window>	O
initiates	O
actions	O
(	O
move	O
,	O
close	O
...	O
)	O
on	O
VisualWorks	B-Application
windows	B-Application
.	O
</s>
<s>
File-in	O
format	O
is	O
the	O
original	O
Smalltalk	B-Application
format	O
for	O
representing	O
classes	O
as	O
text	O
files	B-Operating_System
.	O
</s>
<s>
These	O
can	O
be	O
"	O
filed	O
in	O
"	O
to	O
the	O
VisualWorks	B-Application
IDE	B-Application
to	O
generate	O
any	O
classes	O
not	O
already	O
contained	O
in	O
the	O
Smalltalk	B-Application
image	B-Operating_System
.	O
</s>
<s>
Every	O
file-in	O
document	O
provides	O
a	O
simple	O
textual	O
representation	O
of	O
a	O
Smalltalk	B-Application
class	B-Application
,	O
or	O
classes	O
,	O
in	O
a	O
text	O
file	O
with	O
a	O
.st	O
suffix	O
.	O
</s>
<s>
It	O
is	O
still	O
supported	O
in	O
VisualWorks	B-Application
,	O
but	O
has	O
been	O
superseded	O
by	O
a	O
Parcels	O
mechanism	O
.	O
</s>
<s>
There	O
are	O
examples	O
in	O
file-in	O
format	O
in	O
the	O
examples	O
subdirectory	B-Application
.	O
</s>
<s>
An	O
Examples	O
Browser	O
is	O
provided	O
as	O
a	O
parcel	O
in	O
the	O
examples	O
directory	B-Application
.	O
</s>
<s>
Several	O
image	B-Operating_System
level	O
switches	O
are	O
available	O
to	O
specify	O
parcel	O
loading	O
on	O
image	B-Operating_System
startup	O
.	O
</s>
<s>
The	O
parcel	O
path	O
is	O
the	O
list	O
of	O
directories	B-Application
where	O
VisualWorks	B-Application
looks	O
for	O
parcels	O
.	O
</s>
<s>
Parcels	O
provide	O
the	O
component	O
technology	O
for	O
VisualWorks	B-Application
.	O
</s>
<s>
The	O
term	O
components	O
,	O
in	O
the	O
VisualWorks	B-Application
sphere	O
,	O
is	O
used	O
to	O
refer	O
to	O
parcels	O
,	O
packages	O
,	O
and	O
bundles	O
when	O
it	O
is	O
not	O
necessary	O
to	O
be	O
specific	O
.	O
</s>
<s>
Every	O
class	B-Application
in	O
the	O
parcel	O
is	O
sent	O
message	O
post	O
Load	O
:	O
the	O
Package	O
,	O
and	O
any	O
action	O
executed	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
Directory-tree	O
view	O
of	O
the	O
parcel	O
path	O
,	O
for	O
finding	O
parcels	O
outside	O
the	O
Suggestions	O
view	O
.	O
</s>
<s>
A	O
Loaded	O
view	O
lists	O
all	O
parcels	O
already	O
in	O
the	O
image	B-Operating_System
.	O
</s>
<s>
A	O
supported	O
VisualWorks	B-Application
product	O
parcel	O
is	O
represented	O
by	O
an	O
icon	O
that	O
looks	O
like	O
a	O
parcel	O
.	O
</s>
<s>
Because	O
of	O
the	O
convoluted	O
history	O
of	O
Smalltalk	B-Application
class	B-Application
development	O
this	O
can	O
be	O
very	O
useful	O
.	O
</s>
<s>
For	O
instance	O
,	O
a	O
parcel	O
icon	O
indicates	O
that	O
the	O
Arbor	O
hypertext	O
system	O
is	O
now	O
VisualWorks	B-Application
supported	O
.	O
</s>
<s>
The	O
initial	O
visual.im	O
image	B-Operating_System
contains	O
minimal	O
development	O
facilities	O
,	O
using	O
basic	O
class	B-Application
libraries	I-Application
.	O
</s>
<s>
Additional	O
class	B-Application
libraries	I-Application
are	O
provided	O
by	O
VisualWorks	B-Application
or	O
third-party	O
vendors	O
,	O
usually	O
as	O
parcel	O
files	B-Operating_System
.	O
</s>
<s>
For	O
most	O
non-Smalltalk	O
development	O
environments	O
,	O
code	B-Library
libraries	I-Library
are	O
imported	O
at	O
compile	O
time	O
,	O
using	O
an	O
include	B-Language
command	B-Device
.	O
</s>
<s>
In	O
Smalltalk	B-Application
,	O
code	B-Library
libraries	I-Library
are	O
loaded	O
into	O
the	O
running	O
system	O
,	O
and	O
become	O
part	O
of	O
the	O
environment	O
.	O
</s>
<s>
The	O
VisualWorks	B-Application
Launcher	O
,	O
usually	O
just	O
called	O
the	O
Launcher	O
,	O
is	O
the	O
control	O
centre	O
for	O
the	O
VisualWorks	B-Application
system	O
.	O
</s>
<s>
Smalltalk	B-Application
is	O
a	O
pure	O
object	B-Language
oriented	I-Language
programming	I-Language
language	I-Language
,	O
which	O
means	O
the	O
only	O
way	O
to	O
get	O
something	O
to	O
happen	O
within	O
Smalltalk	B-Application
is	O
by	O
sending	O
messages	O
to	O
objects	O
.	O
</s>
<s>
VisualWorks	B-Application
uses	O
the	O
Smalltalk-80	B-Application
language	O
as	O
standard	O
,	O
but	O
comes	O
with	O
its	O
own	O
set	O
of	O
classes	O
and	O
methods	B-Language
.	O
</s>
<s>
So	O
even	O
basic	O
classes	O
,	O
like	O
Object	O
,	O
differ	O
from	O
those	O
in	O
other	O
Smalltalk-80	B-Application
IDEs	B-Application
like	O
Squeak	B-Operating_System
and	O
Dolphin	B-Application
Smalltalk	I-Application
.	O
</s>
<s>
The	O
illustrative	O
examples	O
here	O
work	O
in	O
VisualWorks	B-Application
Smalltalk	B-Application
,	O
but	O
may	O
not	O
work	O
in	O
other	O
Smalltalks	B-Application
because	O
the	O
classes	O
and/or	O
methods	B-Language
may	O
differ	O
.	O
</s>
<s>
In	O
traditional	O
object-oriented	B-Language
programming	I-Language
environments	O
a	O
developer	O
directly	O
edits	O
a	O
plain	O
text	O
source	O
code	O
file	O
containing	O
class	B-Application
and	O
method	B-Language
definitions	O
.	O
</s>
<s>
In	O
VisualWorks	B-Application
,	O
like	O
all	O
Smalltalks	B-Application
,	O
everything	O
is	O
an	O
executing	B-Application
object	I-Application
,	O
including	O
classes	O
.	O
</s>
<s>
In	O
browsing	O
Smalltalk	B-Application
classes	O
the	O
developer	O
gleans	O
definitions	O
from	O
executing	O
objects	O
.	O
</s>
<s>
The	O
main	O
browser/editor	O
in	O
VisualWorks	B-Application
is	O
the	O
System	O
Browser	O
.	O
</s>
<s>
It	O
allows	O
the	O
developer	O
to	O
browse	O
classes	O
either	O
in	O
the	O
overall	O
class	B-Application
hierarchy	O
or	O
through	O
their	O
packages	O
.	O
</s>
<s>
It	O
is	O
launched	O
from	O
the	O
VisualWorks	B-Application
Launcher	O
.	O
</s>
<s>
List	O
panes	O
in	O
the	O
System	O
Browser	O
allow	O
developers	O
to	O
navigate	O
to	O
class	B-Application
and	O
method	B-Language
definitions	O
.	O
</s>
<s>
illustrates	O
how	O
VisualWorks	B-Application
can	O
be	O
used	O
to	O
manipulate	O
server	B-Application
log	B-Application
files	I-Application
.	O
</s>
<s>
It	O
illustrates	O
how	O
things	O
like	O
strings	O
and	O
files	B-Operating_System
can	O
be	O
easily	O
subsumed	O
into	O
the	O
object	O
structure	O
within	O
VisualWorks	B-Application
.	O
</s>
<s>
Consider	O
the	O
Smalltalk	B-Application
expression	O
:	O
</s>
<s>
One	O
can	O
evaluate	O
this	O
expression	O
as-is	O
in	O
a	O
VisualWorks	B-Application
workspace	O
using	O
one	O
command	B-Device
in	O
the	O
operate	O
menu	O
.	O
</s>
<s>
An	O
object	O
of	O
class	B-Application
ByteString	O
containing	O
the	O
string	O
(	O
as	O
bytes	B-Application
)	O
and	O
the	O
methods	B-Language
for	O
manipulating	O
it	O
;	O
</s>
<s>
The	O
latter	O
is	O
a	O
simple	O
notebook-like	O
editor	O
containing	O
the	O
contents	O
of	O
the	O
file	O
.	O
</s>
<s>
That	O
is	O
,	O
the	O
evaluation	O
created	O
a	O
filename	B-Device
object	O
as	O
a	O
gateway	O
to	O
the	O
file	O
ws000101.log	O
and	O
opened	O
an	O
editor	O
onto	O
it	O
.	O
</s>
<s>
The	O
source	O
code	O
is	O
available	O
for	O
all	O
these	O
objects	O
,	O
and	O
VisualWorks	B-Application
has	O
a	O
plethora	O
of	O
inspectors	O
,	O
browsers	O
,	O
and	O
other	O
tools	O
for	O
anyone	O
to	O
evaluate	O
and	O
inspect	O
the	O
code	O
in	O
static	O
or	O
dynamic	O
mode	O
.	O
</s>
<s>
are	O
produced	O
for	O
Cincom	B-Application
Smalltalk	B-Application
often	O
,	O
and	O
a	O
exists	O
.	O
</s>
