<s>
A+	B-Language
is	O
a	O
high-level	O
,	O
interactive	O
,	O
interpreted	B-Application
array	B-Application
programming	I-Application
language	I-Application
designed	O
for	O
numerically	O
intensive	O
applications	O
,	O
especially	O
those	O
found	O
in	O
financial	O
applications	O
.	O
</s>
<s>
In	O
1985	O
,	O
Arthur	O
Whitney	O
created	O
the	O
A	B-Language
programming	I-Language
language	I-Language
to	O
replace	O
APL	B-Language
.	O
</s>
<s>
Other	O
developers	O
at	O
Morgan	O
Stanley	O
extended	O
it	O
to	O
A+	B-Language
,	O
adding	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
and	O
other	O
language	O
features	O
.	O
</s>
<s>
The	O
GUI	B-Application
A+	B-Language
was	O
released	O
in	O
1988	O
.	O
</s>
<s>
Arthur	O
Whitney	O
went	O
on	O
to	O
create	O
a	O
proprietary	O
array	B-Application
language	O
named	O
K	B-Application
.	O
Like	O
J	B-Language
,	O
K	B-Application
omits	O
the	O
APL	B-Language
character	O
set	O
.	O
</s>
<s>
It	O
lacks	O
some	O
of	O
the	O
perceived	O
complexities	O
of	O
A+	B-Language
,	O
such	O
as	O
the	O
existence	O
of	O
statements	O
and	O
two	O
different	O
modes	O
of	O
syntax	O
.	O
</s>
<s>
A+	B-Language
provides	O
an	O
extended	O
set	O
of	O
functions	O
and	O
operators	O
,	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
with	O
automatic	O
synchronizing	O
of	O
widgets	O
and	O
variables	O
,	O
asynchronous	O
executing	O
of	O
functions	O
associated	O
with	O
variables	O
and	O
events	O
,	O
dynamic	O
loading	O
of	O
user	O
compiled	O
subroutines	O
,	O
and	O
other	O
features	O
.	O
</s>
<s>
A+	B-Language
runs	O
on	O
many	O
Unix	B-Application
variants	O
,	O
including	O
Linux	B-Application
.	O
</s>
<s>
It	O
is	O
free	B-Application
and	I-Application
open	I-Application
source	I-Application
software	I-Application
released	O
under	O
a	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
A	O
newer	O
GUI	B-Application
has	O
not	O
yet	O
been	O
ported	O
to	O
all	O
supported	O
platforms	O
.	O
</s>
<s>
The	O
A+	B-Language
language	O
implements	O
the	O
following	O
changes	O
to	O
the	O
APL	B-Language
language	I-Language
:	O
</s>
<s>
A+	B-Language
implements	O
an	O
object	O
called	O
a	O
dependency	O
,	O
which	O
is	O
a	O
global	O
variable	O
(	O
the	O
dependent	O
variable	O
)	O
and	O
an	O
associated	O
definition	O
that	O
is	O
like	O
a	O
function	O
with	O
no	O
arguments	O
.	O
</s>
<s>
Interactive	O
A+	B-Language
development	O
is	O
primarily	O
done	O
in	O
the	O
Xemacs	B-Language
editor	O
,	O
through	O
extensions	O
to	O
the	O
editor	O
.	O
</s>
<s>
Because	O
A+	B-Language
code	O
uses	O
the	O
original	O
APL	B-Language
symbols	O
,	O
displaying	O
A+	B-Language
requires	O
a	O
font	O
with	O
those	O
special	O
characters	O
;	O
a	O
font	O
named	O
kapl	O
is	O
provided	O
on	O
the	O
web	O
site	O
for	O
that	O
purpose	O
.	O
</s>
