<s>
PascalABC.NET	B-Language
is	O
a	O
high-level	B-Language
general-purpose	B-Language
programming	I-Language
language	I-Language
supporting	O
multiple	O
paradigms	O
.	O
</s>
<s>
PascalABC.NET	B-Language
is	O
based	O
on	O
Delphi	B-Language
's	O
Object	B-Language
Pascal	I-Language
,	O
but	O
also	O
has	O
influences	O
from	O
C#	B-Application
,	O
Python	B-Language
,	O
Kotlin	B-Language
and	O
Haskell	B-Language
.	O
</s>
<s>
It	O
is	O
distributed	O
both	O
as	O
a	O
command-line	O
tool	O
for	O
Windows	O
(	O
.NET	B-Application
Framework	I-Application
)	O
,	O
Linux	O
and	O
MacOS	O
(	O
Mono	O
)	O
,	O
and	O
with	O
an	O
integrated	B-Application
development	I-Application
environment	I-Application
for	O
Windows	O
and	O
Linux	O
,	O
including	O
interactive	O
debugger	O
,	O
IntelliSense	B-Application
system	O
,	O
form	O
designer	O
,	O
code	O
templates	O
and	O
code	O
auto-formatting	O
.	O
</s>
<s>
PascalABC.NET	B-Language
is	O
implemented	O
for	O
the	O
.NET	B-Application
Framework	I-Application
platform	O
,	O
so	O
that	O
it	O
is	O
compatible	O
with	O
all	O
.NET	B-Application
libraries	O
and	O
utilizes	O
all	O
the	O
features	O
of	O
Common	O
Language	O
Runtime	O
,	O
such	O
as	O
garbage	B-General_Concept
collection	I-General_Concept
,	O
exception	B-General_Concept
handling	I-General_Concept
,	O
and	O
generics	B-Language
.	O
</s>
<s>
tuples	O
,	O
sequences	O
,	O
and	O
lambdas	B-General_Concept
,	O
are	O
based	O
on	O
regular	O
.NET	B-Application
types	O
.	O
</s>
<s>
PascalABC.NET	B-Language
is	O
ideologically	O
close	O
to	O
Oxygene	B-Language
,	O
but	O
,	O
unlike	O
it	O
,	O
provides	O
high	O
compatibility	O
with	O
Delphi	B-Language
.	O
</s>
<s>
PascalABC.NET	B-Language
was	O
developed	O
by	O
a	O
group	O
of	O
enthusiasts	O
at	O
the	O
Institute	O
of	O
Mathematics	O
,	O
Mechanics	O
,	O
and	O
Computer	O
Science	O
in	O
Rostov-on-Don	O
,	O
Russia	O
.	O
</s>
<s>
In	O
2003	O
,	O
a	O
predecessor	O
of	O
the	O
modern	O
PascalABC.NET	B-Language
,	O
called	O
Pascal	B-Application
ABC	O
,	O
was	O
implemented	O
by	O
associate	O
professor	O
Stanislav	O
Mikhalkovich	O
to	O
be	O
used	O
for	O
teaching	O
schoolchildren	O
instead	O
of	O
Turbo	B-Application
Pascal	I-Application
,	O
which	O
became	O
outdated	O
and	O
incompatible	O
with	O
modern	O
operating	O
systems	O
but	O
was	O
still	O
used	O
for	O
educational	O
purposes	O
.	O
</s>
<s>
Pascal	B-Application
ABC	O
was	O
implemented	O
as	O
an	O
interpreted	B-Application
programming	I-Application
language	I-Application
,	O
that	O
led	O
to	O
a	O
significant	O
lack	O
of	O
performance	O
.	O
</s>
<s>
Four	O
years	O
after	O
that	O
it	O
was	O
completely	O
rewritten	O
by	O
students	O
Ivan	O
Bondarev	O
,	O
Alexander	O
Tkachuk	O
,	O
and	O
Sergey	O
Ivanov	O
as	O
a	O
compiled	B-Language
programming	I-Language
language	I-Language
for	O
the	O
.NET	B-Application
platform	I-Application
.	O
</s>
<s>
In	O
2009	O
,	O
PascalABC.NET	B-Language
started	O
to	O
be	O
actively	O
used	O
for	O
teaching	O
high	O
school	O
students	O
.	O
</s>
<s>
It	O
began	O
to	O
be	O
actively	O
used	O
throughout	O
Russia	O
in	O
schools	O
and	O
at	O
programming	O
contests	O
,	O
surpassing	O
FreePascal	B-Operating_System
.	O
</s>
<s>
Since	O
then	O
,	O
the	O
PascalABC.NET	B-Language
developers	O
have	O
set	O
themselves	O
the	O
goal	O
of	O
actively	O
incorporating	O
modern	O
features	O
into	O
the	O
language	O
.	O
</s>
<s>
In	O
the	O
same	O
year	O
,	O
PascalABC.NET	B-Language
became	O
an	O
open	O
source	O
project	O
distributed	O
under	O
the	O
LGPLv3	B-Application
license	I-Application
.	O
</s>
<s>
Designed	O
for	O
education	O
,	O
PascalABC.NET	B-Language
remains	O
the	O
most	O
common	O
programming	O
language	O
in	O
Russian	O
schools	O
and	O
one	O
of	O
the	O
recommended	O
languages	O
for	O
passing	O
the	O
Unified	O
State	O
Exam	O
on	O
informatics	O
.	O
</s>
<s>
PascalABC.NET	B-Language
is	O
widely	O
used	O
as	O
a	O
basic	O
programming	O
language	O
in	O
pedagogical	O
universities	O
for	O
the	O
training	O
of	O
computer	O
science	O
teachers	O
.	O
</s>
<s>
PascalABC.NET	B-Language
is	O
also	O
built	O
into	O
a	O
number	O
of	O
validation	O
systems	O
used	O
for	O
programming	O
competitions	O
.	O
</s>
<s>
In	O
2020	O
,	O
during	O
anti-COVID	O
lockdowns	O
and	O
home	O
schooling	O
period	O
,	O
PascalABC.NET	B-Language
website	O
was	O
ranked	O
3rd	O
in	O
Yandex	O
traffic	O
rating	O
in	O
the	O
"	O
Programming	O
"	O
category	O
,	O
and	O
the	O
number	O
of	O
downloads	O
of	O
the	O
installation	O
kit	O
exceeded	O
10000	O
a	O
day	O
.	O
</s>
<s>
Though	O
the	O
core	O
of	O
the	O
PascalABC.NET	B-Language
community	O
is	O
located	O
in	O
Russia	O
,	O
the	O
language	O
is	O
also	O
known	O
in	O
other	O
countries	O
such	O
as	O
Belarus	O
,	O
Romania	O
,	O
Indonesia	O
,	O
Algeria	O
.	O
</s>
<s>
•	O
loop	O
statement	O
•	O
for	O
loop	O
with	O
a	O
step	O
•	O
foreach	O
loop	O
with	O
an	O
index	O
•	O
a	O
..	O
b	O
ranges	O
•	O
short	O
function	O
definition	O
syntax	O
•	O
method	O
implementation	O
can	O
be	O
placed	O
inside	O
a	O
class	O
definition	O
•	O
sequence	O
of	O
T	O
type	O
as	O
an	O
abstraction	O
of	O
arrays	O
,	O
lists	O
and	O
sets	O
•	O
lambda	B-General_Concept
functions	I-General_Concept
•	O
auto	O
classes	O
-	O
classes	O
with	O
an	O
automatically	O
generated	O
constructor	O
•	O
one-dimentional	O
and	O
multi-dimentional	O
array	O
slicesSome	O
other	O
features	O
such	O
as	O
inline	O
variable	O
declarations	O
,	O
type	O
inference	O
,	O
and	O
for	O
statement	O
with	O
a	O
variable	O
declaration	O
are	O
standard	O
in	O
the	O
current	O
version	O
of	O
Delphi	B-Language
.	O
</s>
<s>
However	O
,	O
PascalABC.NET	B-Language
pioneered	O
these	O
features	O
in	O
2007	O
,	O
while	O
in	O
Delphi	B-Language
they	O
were	O
implemented	O
in	O
2018	O
.	O
</s>
<s>
In	O
PascalABC.NET	B-Language
,	O
functions	O
are	O
first-class	O
objects	O
.	O
</s>
<s>
Functional	B-Language
type	O
is	O
set	O
in	O
the	O
form	O
T	O
->	O
Res	O
.	O
</s>
<s>
An	O
anonymous	B-General_Concept
function	I-General_Concept
can	O
be	O
assigned	O
to	O
the	O
variable	O
of	O
this	O
type	O
:	O
</s>
<s>
Here	O
is	O
an	O
example	O
of	O
superposition	B-Application
of	O
two	O
functions	O
:	O
</s>
<s>
Superposition	B-Application
operation	O
is	O
defined	O
in	O
the	O
standard	O
library	O
:	O
</s>
<s>
In	O
the	O
book	O
"	O
How	O
To	O
Program	O
Effectively	O
In	O
Delphi	B-Language
"	O
and	O
in	O
the	O
corresponding	O
video	O
tutorials	O
,	O
Dr.	O
Kevin	O
Bond	O
,	O
a	O
programmer	O
and	O
a	O
Computer	O
Science	O
teaching	O
specialist	O
,	O
notes	O
that	O
PascalABC.NET	B-Language
has	O
powerful	O
functional	B-Language
programming	I-Language
capabilities	O
which	O
are	O
missing	O
in	O
Delphi	B-Language
.	O
</s>
<s>
As	O
an	O
example	O
,	O
partial	B-Application
function	I-Application
application	I-Application
is	O
demonstrated	O
:	O
</s>
<s>
PascalABC.NET	B-Language
is	O
a	O
multi-paradigm	O
programming	O
language	O
.	O
</s>
<s>
It	O
allows	O
one	O
to	O
use	O
different	O
coding	O
styles	O
from	O
oldschool	O
Pascal	B-Application
to	O
functional	B-Language
and	O
object-oriented	B-Language
programming	I-Language
.	O
</s>
<s>
This	O
solution	O
uses	O
.NET	B-Application
extension	O
methods	O
for	O
sequences	O
and	O
PascalABC.NET-specific	O
range	O
(	O
a	O
..	O
b	O
)	O
.	O
</s>
<s>
This	O
solution	O
demonstrates	O
PascalABC.NET-specific	O
short	O
function	O
definition	O
style	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
write	O
programs	O
without	O
usage	O
of	O
PascalABC.NET	B-Language
standard	O
library	O
.	O
</s>
<s>
All	O
standard	O
.NET	B-Application
Framework	I-Application
classes	O
and	O
methods	O
can	O
be	O
used	O
directly	O
.	O
</s>
<s>
Though	O
PascalABC.NET	B-Language
is	O
actively	O
used	O
for	O
teacher	O
traning	O
,	O
some	O
members	O
of	O
the	O
teaching	O
community	O
ignore	O
difference	O
between	O
historically	O
used	O
Turbo	B-Application
Pascal	I-Application
and	O
PascalABC.NET	B-Language
,	O
criticizing	O
some	O
unspecified	O
"	O
Pascal	B-Application
"	O
language	O
for	O
being	O
far	O
from	O
modern	O
programming	O
,	O
too	O
wordy	O
and	O
not	O
simple	O
enough	O
to	O
be	O
used	O
as	O
the	O
first	O
programming	O
language	O
.	O
</s>
<s>
They	O
consider	O
Python	B-Language
to	O
be	O
the	O
best	O
starting	O
point	O
,	O
as	O
it	O
is	O
more	O
concise	O
and	O
practically	O
applicable	O
.	O
</s>
<s>
Their	O
opponents	O
,	O
including	O
PascalABC.NET	B-Language
developers	O
themselves	O
,	O
argue	O
that	O
it	O
is	O
incorrect	O
to	O
put	O
an	O
equal	O
sign	O
between	O
the	O
classic	O
Pascal	B-Application
and	O
PascalABC.NET	B-Language
,	O
as	O
the	O
latter	O
contains	O
lots	O
of	O
modern	O
multi-paradigm	O
features	O
,	O
including	O
the	O
ones	O
from	O
Python	B-Language
.	O
</s>
<s>
PascalABC.NET	B-Language
allows	O
students	O
to	O
write	O
as	O
concise	O
and	O
expressive	O
programs	O
as	O
Python	B-Language
,	O
and	O
acts	O
as	O
a	O
"	O
bridge	O
to	O
production	O
programming	O
"	O
by	O
applying	O
a	O
static	O
typing	O
concept	O
.	O
</s>
<s>
PascalABC.NET	B-Language
is	O
also	O
a	O
compilable	O
language	O
,	O
which	O
makes	O
it	O
easier	O
to	O
learn	O
programming	O
,	O
because	O
all	O
semantic	O
errors	O
are	O
caught	O
at	O
compile	O
time	O
rather	O
than	O
occur	O
unpredictably	O
at	O
runtime	O
.	O
</s>
