<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
a	O
high-level	B-Language
programming	I-Language
language	I-Language
is	O
a	O
programming	O
language	O
with	O
strong	O
abstraction	B-Application
from	O
the	O
details	O
of	O
the	O
computer	O
.	O
</s>
<s>
In	O
contrast	O
to	O
low-level	B-Language
programming	I-Language
languages	I-Language
,	O
it	O
may	O
use	O
natural	O
language	O
elements	O
,	O
be	O
easier	O
to	O
use	O
,	O
or	O
may	O
automate	O
(	O
or	O
even	O
hide	O
entirely	O
)	O
significant	O
areas	O
of	O
computing	O
systems	O
(	O
e.g.	O
</s>
<s>
memory	B-General_Concept
management	I-General_Concept
)	O
,	O
making	O
the	O
process	O
of	O
developing	O
a	O
program	O
simpler	O
and	O
more	O
understandable	O
than	O
when	O
using	O
a	O
lower-level	O
language	O
.	O
</s>
<s>
The	O
amount	O
of	O
abstraction	B-Application
provided	O
defines	O
how	O
"	O
high-level	O
"	O
a	O
programming	O
language	O
is	O
.	O
</s>
<s>
In	O
the	O
1960s	O
,	O
a	O
high-level	B-Language
programming	I-Language
language	I-Language
using	O
a	O
compiler	B-Language
was	O
commonly	O
called	O
an	O
autocode	B-Language
.	O
</s>
<s>
Examples	O
of	O
autocodes	B-Language
are	O
COBOL	B-Application
and	O
Fortran	B-Application
.	O
</s>
<s>
The	O
first	O
high-level	B-Language
programming	I-Language
language	I-Language
designed	O
for	O
computers	O
was	O
Plankalkül	B-Language
,	O
created	O
by	O
Konrad	O
Zuse	O
.	O
</s>
<s>
However	O
,	O
it	O
was	O
not	O
implemented	O
in	O
his	O
time	O
,	O
and	O
his	O
original	O
contributions	O
were	O
largely	O
isolated	O
from	O
other	O
developments	O
due	O
to	O
World	O
War	O
II	O
,	O
aside	O
from	O
the	O
language	O
's	O
influence	O
on	O
the	O
"	O
Superplan	O
"	O
language	O
by	O
Heinz	O
Rutishauser	O
and	O
also	O
to	O
some	O
degree	O
ALGOL	B-Language
.	O
</s>
<s>
The	O
first	O
significantly	O
widespread	O
high-level	B-Language
language	I-Language
was	O
Fortran	B-Application
,	O
a	O
machine-independent	O
development	O
of	O
IBM	O
's	O
earlier	O
Autocode	B-Language
systems	O
.	O
</s>
<s>
The	O
ALGOL	B-Language
family	I-Language
,	O
with	O
ALGOL	B-Language
58	I-Language
defined	O
in	O
1958	O
and	O
ALGOL	B-Language
60	I-Language
defined	O
in	O
1960	O
by	O
committees	O
of	O
European	O
and	O
American	O
computer	B-General_Concept
scientists	I-General_Concept
,	O
introduced	O
recursion	O
as	O
well	O
as	O
nested	O
functions	O
under	O
lexical	O
scope	O
.	O
</s>
<s>
ALGOL	B-Language
60	I-Language
was	O
also	O
the	O
first	O
language	O
with	O
a	O
clear	O
distinction	O
between	O
value	O
and	O
name-parameters	O
and	O
their	O
corresponding	O
semantics	B-Application
.	O
</s>
<s>
ALGOL	B-Language
also	O
introduced	O
several	O
structured	B-Language
programming	I-Language
concepts	O
,	O
such	O
as	O
the	O
while-do	O
and	O
if-then-else	O
constructs	O
and	O
its	O
syntax	O
was	O
the	O
first	O
to	O
be	O
described	O
in	O
formal	O
notation	O
–	O
Backus	O
–	O
Naur	O
form	O
(	O
BNF	O
)	O
.	O
</s>
<s>
During	O
roughly	O
the	O
same	O
period	O
,	O
COBOL	B-Application
introduced	O
records	O
(	O
also	O
called	O
structs	B-Application
)	O
and	O
Lisp	B-Language
introduced	O
a	O
fully	O
general	O
lambda	B-Language
abstraction	I-Language
in	O
a	O
programming	O
language	O
for	O
the	O
first	O
time	O
.	O
</s>
<s>
"	O
High-level	B-Language
language	I-Language
"	O
refers	O
to	O
the	O
higher	O
level	O
of	O
abstraction	B-Application
from	O
machine	B-Language
language	I-Language
.	O
</s>
<s>
Rather	O
than	O
dealing	O
with	O
registers	O
,	O
memory	O
addresses	O
,	O
and	O
call	O
stacks	O
,	O
high-level	B-Language
languages	I-Language
deal	O
with	O
variables	O
,	O
arrays	O
,	O
objects	O
,	O
complex	O
arithmetic	O
or	O
boolean	O
expressions	O
,	O
subroutines	O
and	O
functions	O
,	O
loops	O
,	O
threads	B-Operating_System
,	O
locks	O
,	O
and	O
other	O
abstract	O
computer	B-General_Concept
science	I-General_Concept
concepts	O
,	O
with	O
a	O
focus	O
on	O
usability	B-General_Concept
over	O
optimal	O
program	O
efficiency	O
.	O
</s>
<s>
Unlike	O
low-level	B-Language
assembly	B-Language
languages	I-Language
,	O
high-level	B-Language
languages	I-Language
have	O
few	O
,	O
if	O
any	O
,	O
language	O
elements	O
that	O
translate	O
directly	O
into	O
a	O
machine	O
's	O
native	O
opcodes	B-Language
.	O
</s>
<s>
One	O
thing	O
to	O
note	O
about	O
high-level	B-Language
programming	I-Language
languages	I-Language
is	O
that	O
these	O
languages	O
allow	O
the	O
programmer	O
to	O
be	O
detached	O
and	O
separated	O
from	O
the	O
machine	O
.	O
</s>
<s>
That	O
is	O
,	O
unlike	O
low-level	B-Language
languages	I-Language
like	O
assembly	O
or	O
machine	B-Language
language	I-Language
,	O
high-level	B-Language
programming	I-Language
can	O
amplify	O
the	O
programmer	O
's	O
instructions	O
and	O
trigger	O
a	O
lot	O
of	O
data	O
movements	O
in	O
the	O
background	O
without	O
their	O
knowledge	O
.	O
</s>
<s>
High-level	B-Language
languages	I-Language
intend	O
to	O
provide	O
features	O
that	O
standardize	O
common	O
tasks	O
,	O
permit	O
rich	O
debugging	O
,	O
and	O
maintain	O
architectural	O
agnosticism	O
;	O
while	O
low-level	B-Language
languages	I-Language
often	O
produce	O
more	O
efficient	O
code	O
through	O
optimization	O
for	O
a	O
specific	O
system	O
architecture	O
.	O
</s>
<s>
Abstraction	B-Application
penalty	O
is	O
the	O
cost	O
that	O
high-level	B-Language
programming	I-Language
techniques	O
pay	O
for	O
being	O
unable	O
to	O
optimize	O
performance	O
or	O
use	O
certain	O
hardware	O
because	O
they	O
do	O
n't	O
take	O
advantage	O
of	O
certain	O
low-level	B-Language
architectural	O
resources	O
.	O
</s>
<s>
High-level	B-Language
programming	I-Language
exhibits	O
features	O
like	O
more	O
generic	O
data	B-General_Concept
structures	I-General_Concept
and	O
operations	O
,	O
run-time	O
interpretation	O
,	O
and	O
intermediate	O
code	O
files	O
;	O
which	O
often	O
result	O
in	O
execution	O
of	O
far	O
more	O
operations	O
than	O
necessary	O
,	O
higher	O
memory	O
consumption	O
,	O
and	O
larger	O
binary	O
program	O
size	O
.	O
</s>
<s>
In	O
many	O
cases	O
,	O
critical	O
portions	O
of	O
a	O
program	O
mostly	O
in	O
a	O
high-level	B-Language
language	I-Language
can	O
be	O
hand-coded	O
in	O
assembly	B-Language
language	I-Language
,	O
leading	O
to	O
a	O
much	O
faster	O
,	O
more	O
efficient	O
,	O
or	O
simply	O
reliably	O
functioning	O
optimised	O
program	O
.	O
</s>
<s>
However	O
,	O
with	O
the	O
growing	O
complexity	O
of	O
modern	O
microprocessor	B-Architecture
architectures	O
,	O
well-designed	O
compilers	B-Language
for	O
high-level	B-Language
languages	I-Language
frequently	O
produce	O
code	O
comparable	O
in	O
efficiency	O
to	O
what	O
most	O
low-level	B-Language
programmers	O
can	O
produce	O
by	O
hand	O
,	O
and	O
the	O
higher	O
abstraction	B-Application
may	O
allow	O
for	O
more	O
powerful	O
techniques	O
providing	O
better	O
overall	O
results	O
than	O
their	O
low-level	B-Language
counterparts	O
in	O
particular	O
settings	O
.	O
</s>
<s>
High-level	B-Language
languages	I-Language
are	O
designed	O
independent	O
of	O
a	O
specific	O
computing	O
system	O
architecture	O
.	O
</s>
<s>
This	O
facilitates	O
executing	O
a	O
program	O
written	O
in	O
such	O
a	O
language	O
on	O
any	O
computing	O
system	O
with	O
compatible	O
support	O
for	O
the	O
Interpreted	B-Application
or	O
JIT	O
program	O
.	O
</s>
<s>
High-level	B-Language
languages	I-Language
can	O
be	O
improved	O
as	O
their	O
designers	O
develop	O
improvements	O
.	O
</s>
<s>
In	O
other	O
cases	O
,	O
new	O
high-level	B-Language
languages	I-Language
evolve	O
from	O
one	O
or	O
more	O
others	O
with	O
the	O
goal	O
of	O
aggregating	O
the	O
most	O
popular	O
constructs	O
with	O
new	O
or	O
improved	O
features	O
.	O
</s>
<s>
An	O
example	O
of	O
this	O
is	O
Scala	B-Application
which	O
maintains	O
backward	O
compatibility	O
with	O
Java	B-Language
which	O
means	O
that	O
programs	O
and	O
libraries	O
written	O
in	O
Java	B-Language
will	O
continue	O
to	O
be	O
usable	B-General_Concept
even	O
if	O
a	O
programming	O
shop	O
switches	O
to	O
Scala	B-Application
;	O
this	O
makes	O
the	O
transition	O
easier	O
and	O
the	O
lifespan	O
of	O
such	O
high-level	O
coding	O
indefinite	O
.	O
</s>
<s>
In	O
contrast	O
,	O
low-level	B-Language
programs	O
rarely	O
survive	O
beyond	O
the	O
system	O
architecture	O
which	O
they	O
were	O
written	O
for	O
without	O
major	O
revision	O
.	O
</s>
<s>
This	O
is	O
the	O
engineering	O
'	O
trade-off	O
'	O
for	O
the	O
'	O
Abstraction	B-Application
Penalty	O
 '	O
.	O
</s>
<s>
Examples	O
of	O
high-level	B-Language
programming	I-Language
languages	I-Language
in	O
active	O
use	O
today	O
include	O
Python	B-Language
,	O
JavaScript	B-Language
,	O
Visual	B-Language
Basic	I-Language
,	O
Delphi	B-Language
,	O
Perl	B-Language
,	O
PHP	B-Application
,	O
ECMAScript	B-Language
,	O
Ruby	B-Language
,	O
C#	B-Application
,	O
Java	B-Language
and	O
many	O
others	O
.	O
</s>
<s>
The	O
terms	O
high-level	O
and	O
low-level	B-Language
are	O
inherently	O
relative	O
.	O
</s>
<s>
Some	O
decades	O
ago	O
,	O
the	O
C	B-Language
language	I-Language
,	O
and	O
similar	O
languages	O
,	O
were	O
most	O
often	O
considered	O
"	O
high-level	O
"	O
,	O
as	O
it	O
supported	O
concepts	O
such	O
as	O
expression	O
evaluation	O
,	O
parameterised	O
recursive	O
functions	O
,	O
and	O
data	O
types	O
and	O
structures	O
,	O
while	O
assembly	B-Language
language	I-Language
was	O
considered	O
"	O
low-level	B-Language
"	O
.	O
</s>
<s>
Today	O
,	O
many	O
programmers	O
might	O
refer	O
to	O
C	B-Language
as	O
low-level	B-Language
,	O
as	O
it	O
lacks	O
a	O
large	O
runtime-system	O
(	O
no	O
garbage	O
collection	O
,	O
etc	O
.	O
</s>
<s>
It	O
,	O
therefore	O
,	O
readily	O
blends	O
with	O
assembly	B-Language
language	I-Language
and	O
the	O
machine	O
level	O
of	O
CPUs	B-Device
and	O
microcontrollers	B-Architecture
.	O
</s>
<s>
Also	O
,	O
in	O
the	O
introduction	O
chapter	O
of	O
The	O
C	B-Language
Programming	I-Language
Language	I-Language
(	O
second	O
edition	O
)	O
by	O
K&R	O
,	O
C	B-Language
is	O
considered	O
as	O
a	O
relatively	O
"	O
low	O
level	O
"	O
language	O
.	O
</s>
<s>
Assembly	B-Language
language	I-Language
may	O
itself	O
be	O
regarded	O
as	O
a	O
higher	O
level	O
(	O
but	O
often	O
still	O
one-to-one	O
if	O
used	O
without	O
macros	O
)	O
representation	O
of	O
machine	B-Language
code	I-Language
,	O
as	O
it	O
supports	O
concepts	O
such	O
as	O
constants	O
and	O
(	O
limited	O
)	O
expressions	O
,	O
sometimes	O
even	O
variables	O
,	O
procedures	O
,	O
and	O
data	B-General_Concept
structures	I-General_Concept
.	O
</s>
<s>
Machine	B-Language
code	I-Language
,	O
in	O
its	O
turn	O
,	O
is	O
inherently	O
at	O
a	O
slightly	O
higher	O
level	O
than	O
the	O
microcode	B-Device
or	O
micro-operations	B-General_Concept
used	O
internally	O
in	O
many	O
processors	O
.	O
</s>
<s>
There	O
are	O
three	O
general	O
modes	O
of	O
execution	O
for	O
modern	O
high-level	B-Language
languages	I-Language
:	O
</s>
<s>
Interpreted	B-Application
When	O
code	O
written	O
in	O
a	O
language	O
is	O
interpreted	B-Application
,	O
its	O
syntax	O
is	O
read	O
and	O
then	O
executed	O
directly	O
,	O
with	O
no	O
compilation	B-Language
stage	O
.	O
</s>
<s>
A	O
program	O
called	O
an	O
interpreter	B-Application
reads	O
each	O
program	O
statement	O
,	O
following	O
the	O
program	O
flow	O
,	O
then	O
decides	O
what	O
to	O
do	O
,	O
and	O
does	O
it	O
.	O
</s>
<s>
A	O
hybrid	O
of	O
an	O
interpreter	B-Application
and	O
a	O
compiler	B-Language
will	O
compile	B-Language
the	O
statement	O
into	O
machine	B-Language
code	I-Language
and	O
execute	O
that	O
;	O
the	O
machine	B-Language
code	I-Language
is	O
then	O
discarded	O
,	O
to	O
be	O
interpreted	B-Application
anew	O
if	O
the	O
line	O
is	O
executed	O
again	O
.	O
</s>
<s>
Interpreters	B-Application
are	O
commonly	O
the	O
simplest	O
implementations	O
of	O
the	O
behavior	O
of	O
a	O
language	O
,	O
compared	O
to	O
the	O
other	O
two	O
variants	O
listed	O
here	O
.	O
</s>
<s>
Compiled	B-Language
When	O
code	O
written	O
in	O
a	O
language	O
is	O
compiled	B-Language
,	O
its	O
syntax	O
is	O
transformed	O
into	O
an	O
executable	O
form	O
before	O
running	O
.	O
</s>
<s>
There	O
are	O
two	O
types	O
of	O
compilation	B-Language
:	O
</s>
<s>
Machine	B-Language
code	I-Language
generation	O
Some	O
compilers	B-Language
compile	B-Language
source	O
code	O
directly	O
into	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
This	O
is	O
the	O
original	O
mode	O
of	O
compilation	B-Language
,	O
and	O
languages	O
that	O
are	O
directly	O
and	O
completely	O
transformed	O
to	O
machine-native	O
code	O
in	O
this	O
way	O
may	O
be	O
called	O
truly	O
compiled	B-Language
languages	I-Language
.	O
</s>
<s>
See	O
assembly	B-Language
language	I-Language
.	O
</s>
<s>
Intermediate	B-Application
representations	I-Application
When	O
code	O
written	O
in	O
a	O
language	O
is	O
compiled	B-Language
to	O
an	O
intermediate	B-Application
representation	I-Application
,	O
that	O
representation	O
can	O
be	O
optimized	O
or	O
saved	O
for	O
later	O
execution	O
without	O
the	O
need	O
to	O
re-read	O
the	O
source	O
file	O
.	O
</s>
<s>
When	O
the	O
intermediate	B-Application
representation	I-Application
is	O
saved	O
,	O
it	O
may	O
be	O
in	O
a	O
form	O
such	O
as	O
bytecode	O
.	O
</s>
<s>
The	O
intermediate	B-Application
representation	I-Application
must	O
then	O
be	O
interpreted	B-Application
or	O
further	O
compiled	B-Language
to	O
execute	O
it	O
.	O
</s>
<s>
Virtual	B-Architecture
machines	I-Architecture
that	O
execute	O
bytecode	O
directly	O
or	O
transform	O
it	O
further	O
into	O
machine	B-Language
code	I-Language
have	O
blurred	O
the	O
once	O
clear	O
distinction	O
between	O
intermediate	B-Application
representations	I-Application
and	O
truly	O
compiled	B-Language
languages	I-Language
.	O
</s>
<s>
Source-to-source	O
translated	O
or	O
transcompiled	B-Language
Code	O
written	O
in	O
a	O
language	O
may	O
be	O
translated	O
into	O
terms	O
of	O
a	O
lower-level	O
language	O
for	O
which	O
native	B-Language
code	I-Language
compilers	B-Language
are	O
already	O
common	O
.	O
</s>
<s>
JavaScript	B-Language
and	O
the	O
language	O
C	B-Language
are	O
common	O
targets	O
for	O
such	O
translators	O
.	O
</s>
<s>
See	O
CoffeeScript	B-Application
,	O
Chicken	B-Language
Scheme	I-Language
,	O
and	O
Eiffel	B-Language
as	O
examples	O
.	O
</s>
<s>
Specifically	O
,	O
the	O
generated	O
C	B-Language
and	O
C++	O
code	O
can	O
be	O
seen	O
(	O
as	O
generated	O
from	O
the	O
Eiffel	B-Language
language	O
when	O
using	O
the	O
EiffelStudio	B-Application
IDE	O
)	O
in	O
the	O
EIFGENs	O
directory	O
of	O
any	O
compiled	B-Language
Eiffel	B-Language
project	O
.	O
</s>
<s>
In	O
Eiffel	B-Language
,	O
the	O
translated	O
process	O
is	O
referred	O
to	O
as	O
transcompiling	B-Language
or	O
transcompiled	B-Language
,	O
and	O
the	O
Eiffel	B-Language
compiler	B-Language
as	O
a	O
transcompiler	B-Language
or	O
source-to-source	B-Language
compiler	I-Language
.	O
</s>
<s>
Note	O
that	O
languages	O
are	O
not	O
strictly	O
interpreted	B-Application
languages	I-Application
or	O
compiled	B-Language
languages	I-Language
.	O
</s>
<s>
Rather	O
,	O
implementations	O
of	O
language	O
behavior	O
use	O
interpreting	O
or	O
compiling	B-Language
.	O
</s>
<s>
For	O
example	O
,	O
ALGOL	B-Language
60	I-Language
and	O
Fortran	B-Application
have	O
both	O
been	O
interpreted	B-Application
(	O
even	O
though	O
they	O
were	O
more	O
typically	O
compiled	B-Language
)	O
.	O
</s>
<s>
Similarly	O
,	O
Java	B-Language
shows	O
the	O
difficulty	O
of	O
trying	O
to	O
apply	O
these	O
labels	O
to	O
languages	O
,	O
rather	O
than	O
to	O
implementations	O
;	O
Java	B-Language
is	O
compiled	B-Language
to	O
bytecode	O
which	O
is	O
then	O
executed	O
by	O
either	O
interpreting	O
(	O
in	O
a	O
Java	B-Language
virtual	I-Language
machine	I-Language
(	O
JVM	B-Language
)	O
)	O
or	O
compiling	B-Language
(	O
typically	O
with	O
a	O
just-in-time	O
compiler	B-Language
such	O
as	O
HotSpot	B-Language
,	O
again	O
in	O
a	O
JVM	B-Language
)	O
.	O
</s>
<s>
Moreover	O
,	O
compiling	B-Language
,	O
transcompiling	B-Language
,	O
and	O
interpreting	O
is	O
not	O
strictly	O
limited	O
to	O
only	O
a	O
description	O
of	O
the	O
compiler	B-Language
artifact	O
(	O
binary	O
executable	O
or	O
IL	O
assembly	O
)	O
.	O
</s>
<s>
Alternatively	O
,	O
it	O
is	O
possible	O
for	O
a	O
high-level	B-Language
language	I-Language
to	O
be	O
directly	O
implemented	O
by	O
a	O
computer	O
–	O
the	O
computer	O
directly	O
executes	O
the	O
HLL	O
code	O
.	O
</s>
<s>
This	O
is	O
known	O
as	O
a	O
high-level	B-Architecture
language	I-Architecture
computer	I-Architecture
architecture	I-Architecture
–	O
the	O
computer	B-General_Concept
architecture	I-General_Concept
itself	O
is	O
designed	O
to	O
be	O
targeted	O
by	O
a	O
specific	O
high-level	B-Language
language	I-Language
.	O
</s>
<s>
The	O
Burroughs	B-Device
large	I-Device
systems	I-Device
were	O
target	O
machines	O
for	O
ALGOL	B-Language
60	I-Language
,	O
for	O
example	O
.	O
</s>
