<s>
Proteus	B-Language
(	O
PROcessor	O
for	O
TExt	O
Easy	O
to	O
USe	O
)	O
is	O
a	O
fully	O
functional	O
,	O
procedural	O
programming	O
language	O
created	O
in	O
1998	O
by	O
Simone	O
Zanella	O
.	O
</s>
<s>
languages	O
:	O
C	B-Language
,	O
BASIC	O
,	O
Assembly	O
,	O
Clipper/dBase	O
;	O
</s>
<s>
Proteus	B-Language
owes	O
its	O
name	O
to	O
a	O
Greek	O
god	O
of	O
the	O
sea	O
(	O
Proteus	B-Language
)	O
,	O
who	O
took	O
care	O
of	O
Neptune	O
's	O
crowd	O
and	O
gave	O
responses	O
;	O
he	O
was	O
renowned	O
for	O
being	O
able	O
to	O
transform	O
himself	O
,	O
assuming	O
different	O
shapes	O
.	O
</s>
<s>
Proteus	B-Language
was	O
initially	O
created	O
as	O
a	O
multiplatform	O
(	O
DOS	B-Device
,	O
Windows	O
,	O
Unix	B-Application
)	O
system	O
utility	O
,	O
to	O
manipulate	O
text	O
and	O
binary	O
files	O
and	O
to	O
create	O
CGI	B-Language
scripts	I-Language
.	O
</s>
<s>
adding	O
hundreds	O
of	O
specialized	O
functions	O
for	O
:	O
network	O
and	O
serial	O
communication	O
,	O
database	O
interrogation	O
,	O
system	O
service	O
creation	O
,	O
console	O
applications	O
,	O
keyboard	O
emulation	O
,	O
ISAPI	B-Library
scripting	O
(	O
for	O
IIS	B-Application
)	O
.	O
</s>
<s>
Proteus	B-Language
was	O
designed	O
to	O
be	O
practical	O
(	O
easy	O
to	O
use	O
,	O
efficient	O
,	O
complete	O
)	O
,	O
readable	O
and	O
consistent	O
.	O
</s>
<s>
comprehensibility	O
of	O
Proteus	B-Language
scripts	O
;	O
</s>
<s>
availability	O
of	O
advanced	O
data	O
structures	O
:	O
arrays	B-Data_Structure
,	O
queues	B-Application
(	O
single	O
or	O
double	O
)	O
,	O
stacks	B-Application
,	O
bit	B-Data_Structure
maps	I-Data_Structure
,	O
sets	O
,	O
AVL	O
trees	O
.	O
</s>
<s>
The	O
language	O
can	O
be	O
extended	O
by	O
adding	O
user	O
functions	O
written	O
in	O
Proteus	B-Language
or	O
DLLs	O
created	O
in	O
C/C	O
++	O
.	O
</s>
<s>
Proteus	B-Language
has	O
a	O
fully	O
functional	O
,	O
procedural	O
approach	O
;	O
</s>
<s>
Data	O
types	O
supported	O
by	O
Proteus	B-Language
are	O
only	O
three	O
:	O
integer	O
numbers	O
,	O
floating	O
point	O
numbers	O
and	O
strings	O
.	O
</s>
<s>
Proteus	B-Language
includes	O
hundreds	O
of	O
functions	O
for	O
:	O
</s>
<s>
Two	O
types	O
of	O
regular	B-Language
expressions	I-Language
are	O
supported	O
:	O
</s>
<s>
extended	O
(	O
Unix	B-Application
like	O
)	O
;	O
</s>
<s>
basic	O
(	O
Dos	B-Device
like	O
,	O
having	O
just	O
the	O
wildcards	O
"	O
?	O
"	O
</s>
<s>
ISAPI	B-Library
scripts	O
.	O
</s>
<s>
For	O
intellectual	O
property	O
protection	O
Proteus	B-Language
provides	O
:	O
</s>
<s>
Proteus	B-Language
is	O
appreciated	O
because	O
it	O
is	O
relatively	O
easy	O
to	O
write	O
short	O
,	O
powerful	O
and	O
comprehensible	O
scripts	O
;	O
</s>
<s>
The	O
development	O
environment	O
includes	O
a	O
source	B-Application
code	I-Application
editor	I-Application
with	O
syntax	O
highlighting	O
and	O
a	O
context-sensitive	O
guide	O
.	O
</s>
<s>
multi-language	O
support	O
:	O
Proteus	B-Language
is	O
available	O
in	O
several	O
languages	O
(	O
keywords	O
and	O
messages	O
)	O
;	O
</s>
<s>
no	O
data	O
types	O
:	O
all	O
variables	O
can	O
be	O
used	O
as	O
integer	O
numbers	O
,	O
floating	O
point	O
numbers	O
or	O
strings	O
;	O
variables	O
are	O
interpreted	O
according	O
to	O
the	O
functions	O
being	O
applied	O
–	O
Proteus	B-Language
keeps	O
different	O
representations	O
of	O
their	O
values	O
between	O
calls	O
,	O
to	O
decrease	O
execution	O
time	O
in	O
case	O
of	O
frequent	O
conversions	O
between	O
one	O
type	O
and	O
the	O
other	O
;	O
</s>
<s>
no	O
pre-allocated	O
structures	O
:	O
all	O
data	O
used	O
by	O
Proteus	B-Language
are	O
dynamically	O
allocated	O
at	O
execution	O
time	O
;	O
there	O
are	O
no	O
limits	O
on	O
:	O
recursion	O
,	O
maximum	O
data	O
size	O
,	O
number	O
of	O
variables	O
,	O
etc	O
.	O
</s>
<s>
no	O
operators	O
:	O
Proteus	B-Language
is	O
a	O
completely	O
functional	O
language	O
–	O
there	O
are	O
no	O
operators	O
;	O
thus	O
,	O
there	O
is	O
no	O
ambiguity	O
when	O
evaluating	O
expressions	O
and	O
parenthesis	O
are	O
not	O
needed	O
;	O
</s>
<s>
large	O
library	O
of	O
predefined	O
functions	O
:	O
Proteus	B-Language
is	O
not	O
a	O
toy-language	O
,	O
it	O
comes	O
with	O
hundreds	O
of	O
library	O
functions	O
ready	O
to	O
be	O
used	O
for	O
working	O
on	O
strings	O
,	O
dates	O
,	O
numbers	O
,	O
for	O
sorting	O
,	O
searching	O
and	O
so	O
on	O
;	O
</s>
<s>
advanced	O
data	O
access	O
(	O
DAO	O
)	O
,	O
pipes	O
,	O
Windows	O
sockets	O
,	O
serial	O
ports	O
:	O
in	O
the	O
Windows	O
version	O
,	O
Proteus	B-Language
includes	O
hundreds	O
of	O
system	O
calls	O
which	O
are	O
operating	O
system-specific	O
;	O
</s>
<s>
clear	O
and	O
comprehensible	O
syntax	O
:	O
the	O
names	O
of	O
the	O
library	O
functions	O
resemble	O
those	O
of	O
corresponding	O
functions	O
in	O
C	B-Language
,	O
Clipper/Flagship	O
and	O
Assembly	O
;	O
by	O
using	O
medium-length	O
keywords	O
,	O
Proteus	B-Language
programs	O
are	O
very	O
easy	O
to	O
understand	O
;	O
</s>
<s>
native	O
support	O
for	O
high-level	O
data	O
structures	O
:	O
arrays	B-Data_Structure
,	O
queues	B-Application
(	O
single	O
or	O
double	O
)	O
,	O
stacks	B-Application
,	O
bit	B-Data_Structure
maps	I-Data_Structure
,	O
sets	O
,	O
AVL	O
trees	O
are	O
already	O
available	O
in	O
Proteus	B-Language
and	O
do	O
not	O
require	O
additional	O
code	O
or	O
libraries	O
to	O
be	O
used	O
;	O
</s>
<s>
ISAPI	B-Library
DLL	O
and	O
Windows	O
Service	O
versions	O
:	O
Proteus	B-Language
is	O
available	O
as	O
a	O
Windows	O
service	O
or	O
as	O
an	O
ISAPI	B-Library
DLL	O
(	O
for	O
using	O
together	O
with	O
Microsoft	B-Application
Internet	I-Application
Information	I-Application
Server	I-Application
)	O
;	O
</s>
<s>
user	O
libraries	O
:	O
it	O
is	O
possible	O
to	O
write	O
user	O
defined	O
functions	O
(	O
UDF	O
)	O
in	O
separate	O
files	O
,	O
and	O
include	O
them	O
(	O
even	O
conditionally	O
and	O
recursively	O
)	O
inside	O
new	O
programs	O
;	O
UDFs	O
can	O
be	O
referenced	O
before	O
or	O
after	O
the	O
definition	O
;	O
it	O
is	O
also	O
possible	O
to	O
write	O
external	O
functions	O
in	O
Visual	O
C++	B-Language
and	O
invoke	O
them	O
from	O
a	O
Proteus	B-Language
script	O
;	O
</s>
<s>
native	O
support	O
for	O
Ms-Dos/Windows	O
,	O
Macintosh	O
and	O
Unix	B-Application
text	O
files	O
(	O
all	O
versions	O
)	O
;	O
</s>
<s>
support	O
for	O
simple	O
(	O
Dos-like	O
)	O
and	O
extended	O
(	O
Unix-like	O
)	O
regular	B-Language
expressions	I-Language
,	O
in	O
all	O
versions	O
;	O
</s>
<s>
Proteus	B-Language
is	O
available	O
in	O
demo	O
version	O
(	O
script	O
execution	O
limited	O
to	O
three	O
minutes	O
)	O
and	O
registered	O
version	O
,	O
</s>
