<s>
SWI-Prolog	B-Application
is	O
a	O
free	B-Application
implementation	O
of	O
the	O
programming	O
language	O
Prolog	B-Language
,	O
commonly	O
used	O
for	O
teaching	O
and	O
semantic	O
web	O
applications	O
.	O
</s>
<s>
It	O
has	O
a	O
rich	O
set	O
of	O
features	O
,	O
libraries	B-Library
for	O
constraint	B-Application
logic	I-Application
programming	I-Application
,	O
multithreading	B-Operating_System
,	O
unit	O
testing	O
,	O
GUI	B-Application
,	O
interfacing	O
to	O
Java	B-Language
,	O
ODBC	B-Application
and	O
others	O
,	O
literate	B-Application
programming	I-Application
,	O
a	O
web	B-Application
server	I-Application
,	O
SGML	B-Language
,	O
RDF	O
,	O
RDFS	O
,	O
developer	O
tools	O
(	O
including	O
an	O
IDE	B-Application
with	O
a	O
GUI	B-Application
debugger	B-Application
and	O
GUI	B-Application
profiler	O
)	O
,	O
and	O
extensive	O
documentation	O
.	O
</s>
<s>
SWI-Prolog	B-Application
runs	O
on	O
Unix	B-Application
,	O
Windows	B-Application
,	O
Macintosh	B-Device
and	O
Linux	B-Application
platforms	O
.	O
</s>
<s>
SWI-Prolog	B-Application
has	O
been	O
under	O
continuous	O
development	O
since	O
1987	O
.	O
</s>
<s>
SWI-Prolog	B-Application
installs	O
with	O
a	O
web	B-Application
framework	I-Application
based	O
on	O
definite	B-Application
clause	I-Application
grammars	I-Application
.	O
</s>
<s>
SWI-Prolog	B-Application
queries	O
may	O
be	O
distributed	O
over	O
several	O
servers	O
and	O
web	O
pages	O
through	O
the	O
Pengines	O
system	O
.	O
</s>
<s>
XPCE	O
is	O
a	O
platform-independent	B-Operating_System
object-oriented	B-Language
GUI	B-Library
toolkit	I-Library
for	O
SWI-Prolog	B-Application
,	O
Lisp	B-Language
and	O
other	O
interactive	O
and	O
dynamically	O
typed	O
languages	O
.	O
</s>
<s>
Although	O
XPCE	O
was	O
designed	O
to	O
be	O
language-independent	O
,	O
it	O
has	O
gained	O
popularity	O
mostly	O
with	O
Prolog	B-Language
.	O
</s>
<s>
The	O
development	O
XPCE	O
graphic	O
toolkit	O
started	O
in	O
1987	O
,	O
together	O
with	O
SWI-Prolog	B-Application
.	O
</s>
<s>
It	O
supports	O
buttons	O
,	O
menus	O
,	O
sliders	O
,	O
tabs	O
and	O
other	O
basic	O
GUI	B-Application
widgets	O
.	O
</s>
<s>
XPCE	O
is	O
available	O
for	O
all	O
platforms	O
supported	O
by	O
SWI-Prolog	B-Application
.	O
</s>
<s>
PceEmacs	O
is	O
a	O
SWI-Prolog	B-Application
builtin	O
editor	O
.	O
</s>
<s>
PceEmacs	O
is	O
an	O
Emacs	B-Application
clone	O
implemented	O
in	O
Prolog	B-Language
(	O
and	O
XPCE	O
)	O
.	O
</s>
<s>
It	O
supports	O
proper	O
indentation	O
,	O
syntax	O
highlighting	O
,	O
full	O
syntax	O
checking	O
by	O
calling	O
the	O
SWI-Prolog	B-Application
parser	B-Language
,	O
warning	O
for	O
singleton	O
variables	O
and	O
finding	O
predicate	O
definitions	O
based	O
on	O
the	O
source	O
information	O
from	O
the	O
Prolog	B-Language
database	O
.	O
</s>
<s>
JPL	O
is	O
a	O
bidirectional	O
interface	O
between	O
Java	B-Language
and	O
Prolog	B-Language
.	O
</s>
<s>
It	O
requires	O
both	O
SWI-Prolog	B-Application
and	O
Java	B-Language
SDK	I-Language
.	O
</s>
<s>
It	O
is	O
installed	O
as	O
a	O
part	O
of	O
SWI-Prolog	B-Application
.	O
</s>
<s>
Constraint	B-Application
logic	I-Application
programming	I-Application
functionality	O
came	O
rather	O
late	O
in	O
the	O
lifetime	O
of	O
SWI-Prolog	B-Application
,	O
because	O
it	O
lacked	O
the	O
basic	O
support	O
.	O
</s>
<s>
The	O
Leuven	O
CHR	O
library	O
was	O
then	O
the	O
first	O
CLP	O
library	O
to	O
be	O
ported	O
to	O
SWI-Prolog	B-Application
.	O
</s>
<s>
We	O
mention	O
SWI-Prolog	B-Application
'	O
s	O
INCLP(R )	O
library	O
(	O
De	O
Koninck	O
et	O
al	O
.	O
</s>
