<s>
Ruby	B-Language
is	O
an	O
interpreted	B-Application
,	O
high-level	B-Language
,	O
general-purpose	B-Language
programming	I-Language
language	I-Language
which	O
supports	O
multiple	O
programming	O
paradigms	O
.	O
</s>
<s>
In	O
Ruby	B-Language
,	O
everything	O
is	O
an	O
object	O
,	O
including	O
primitive	O
data	O
types	O
.	O
</s>
<s>
Ruby	B-Language
is	O
dynamically	O
typed	O
and	O
uses	O
garbage	B-General_Concept
collection	I-General_Concept
and	O
just-in-time	O
compilation	O
.	O
</s>
<s>
It	O
supports	O
multiple	O
programming	O
paradigms	O
,	O
including	O
procedural	B-Application
,	O
object-oriented	B-Language
,	O
and	O
functional	B-Language
programming	I-Language
.	O
</s>
<s>
According	O
to	O
the	O
creator	O
,	O
Ruby	B-Language
was	O
influenced	O
by	O
Perl	B-Language
,	O
Smalltalk	B-Application
,	O
Eiffel	B-Language
,	O
Ada	B-Language
,	O
BASIC	O
,	O
Java	B-Language
and	O
Lisp	B-Language
.	O
</s>
<s>
Matsumoto	O
has	O
said	O
that	O
Ruby	B-Language
was	O
conceived	O
in	O
1993	O
.	O
</s>
<s>
In	O
a	O
1999	O
post	O
to	O
the	O
ruby-talk	O
mailing	O
list	O
,	O
he	O
describes	O
some	O
of	O
his	O
early	O
ideas	O
about	O
the	O
language	O
:	O
</s>
<s>
Matsumoto	O
describes	O
the	O
design	O
of	O
Ruby	B-Language
as	O
being	O
like	O
a	O
simple	O
Lisp	B-Language
language	I-Language
at	O
its	O
core	O
,	O
with	O
an	O
object	B-Language
system	I-Language
like	O
that	O
of	O
Smalltalk	B-Application
,	O
blocks	O
inspired	O
by	O
higher-order	B-Language
functions	I-Language
,	O
and	O
practical	O
utility	O
like	O
that	O
of	O
Perl	B-Language
.	O
</s>
<s>
The	O
name	O
"	O
Ruby	B-Language
"	O
originated	O
during	O
an	O
online	O
chat	O
session	O
between	O
Matsumoto	O
and	O
Keiju	O
Ishitsuka	O
on	O
February	O
24	O
,	O
1993	O
,	O
before	O
any	O
code	O
had	O
been	O
written	O
for	O
the	O
language	O
.	O
</s>
<s>
Initially	O
two	O
names	O
were	O
proposed	O
:	O
"	O
Coral	B-Language
"	O
and	O
"	O
Ruby	B-Language
"	O
.	O
</s>
<s>
Matsumoto	O
later	O
noted	O
a	O
factor	O
in	O
choosing	O
the	O
name	O
"	O
Ruby	B-Language
"	O
–	O
it	O
was	O
the	O
birthstone	O
of	O
one	O
of	O
his	O
colleagues	O
.	O
</s>
<s>
The	O
first	O
public	O
release	O
of	O
Ruby	B-Language
0.95	O
was	O
announced	O
on	O
Japanese	O
domestic	O
newsgroups	B-Application
on	O
December	O
21	O
,	O
1995	O
.	O
</s>
<s>
Subsequently	O
,	O
three	O
more	O
versions	O
of	O
Ruby	B-Language
were	O
released	O
in	O
two	O
days	O
.	O
</s>
<s>
The	O
release	O
coincided	O
with	O
the	O
launch	O
of	O
the	O
Japanese-language	O
ruby-list	O
mailing	O
list	O
,	O
which	O
was	O
the	O
first	O
mailing	O
list	O
for	O
the	O
new	O
language	O
.	O
</s>
<s>
Already	O
present	O
at	O
this	O
stage	O
of	O
development	O
were	O
many	O
of	O
the	O
features	O
familiar	O
in	O
later	O
releases	O
of	O
Ruby	B-Language
,	O
including	O
object-oriented	B-Language
design	O
,	O
classes	O
with	O
inheritance	B-Language
,	O
mixins	B-Language
,	O
iterators	O
,	O
closures	B-Language
,	O
exception	B-General_Concept
handling	I-General_Concept
and	O
garbage	B-General_Concept
collection	I-General_Concept
.	O
</s>
<s>
Following	O
the	O
release	O
of	O
Ruby	B-Language
0.95	O
in	O
1995	O
,	O
several	O
stable	O
versions	O
of	O
Ruby	B-Language
were	O
released	O
in	O
the	O
following	O
years	O
:	O
</s>
<s>
In	O
1997	O
,	O
the	O
first	O
article	O
about	O
Ruby	B-Language
was	O
published	O
on	O
the	O
Web	O
.	O
</s>
<s>
In	O
the	O
same	O
year	O
,	O
Matsumoto	O
was	O
hired	O
by	O
netlab.jp	O
to	O
work	O
on	O
Ruby	B-Language
as	O
a	O
full-time	O
developer	O
.	O
</s>
<s>
In	O
1998	O
,	O
the	O
Ruby	B-Language
Application	O
Archive	O
was	O
launched	O
by	O
Matsumoto	O
,	O
along	O
with	O
a	O
simple	O
English-language	O
homepage	O
for	O
Ruby	B-Language
.	O
</s>
<s>
In	O
1999	O
,	O
the	O
first	O
English	O
language	O
mailing	O
list	O
ruby-talk	O
began	O
,	O
which	O
signaled	O
a	O
growing	O
interest	O
in	O
the	O
language	O
outside	O
Japan	O
.	O
</s>
<s>
In	O
this	O
same	O
year	O
,	O
Matsumoto	O
and	O
Keiju	O
Ishitsuka	O
wrote	O
the	O
first	O
book	O
on	O
Ruby	B-Language
,	O
The	O
Object-oriented	B-Language
Scripting	O
Language	O
Ruby	B-Language
( オブジェクト指向スクリプト言語	O
Ruby	B-Language
)	O
,	O
which	O
was	O
published	O
in	O
Japan	O
in	O
October	O
1999	O
.	O
</s>
<s>
It	O
would	O
be	O
followed	O
in	O
the	O
early	O
2000s	O
by	O
around	O
20	O
books	O
on	O
Ruby	B-Language
published	O
in	O
Japanese	O
.	O
</s>
<s>
By	O
2000	O
,	O
Ruby	B-Language
was	O
more	O
popular	O
than	O
Python	B-Language
in	O
Japan	O
.	O
</s>
<s>
In	O
September	O
2000	O
,	O
the	O
first	O
English	O
language	O
book	O
Programming	B-Language
Ruby	I-Language
was	O
printed	O
,	O
which	O
was	O
later	O
freely	O
released	O
to	O
the	O
public	O
,	O
further	O
widening	O
the	O
adoption	O
of	O
Ruby	B-Language
amongst	O
English	O
speakers	O
.	O
</s>
<s>
In	O
early	O
2002	O
,	O
the	O
English-language	O
ruby-talk	O
mailing	O
list	O
was	O
receiving	O
more	O
messages	O
than	O
the	O
Japanese-language	O
ruby-list	O
,	O
demonstrating	O
Ruby	B-Language
's	O
increasing	O
popularity	O
in	O
the	O
non-Japanese	O
speaking	O
world	O
.	O
</s>
<s>
Ruby	B-Language
1.8	O
was	O
initially	O
released	O
August	O
2003	O
,	O
was	O
stable	O
for	O
a	O
long	O
time	O
,	O
and	O
was	O
retired	O
June	O
2013	O
.	O
</s>
<s>
Ruby	B-Language
1.8	O
is	O
only	O
partially	O
compatible	O
with	O
Ruby	B-Language
1.9	O
.	O
</s>
<s>
Ruby	B-Language
1.8	O
has	O
been	O
the	O
subject	O
of	O
several	O
industry	O
standards	O
.	O
</s>
<s>
The	O
language	O
specifications	O
for	O
Ruby	B-Language
were	O
developed	O
by	O
the	O
Open	O
Standards	O
Promotion	O
Center	O
of	O
the	O
Information-Technology	O
Promotion	O
Agency	O
(	O
a	O
Japanese	O
government	O
agency	O
)	O
for	O
submission	O
to	O
the	O
Japanese	O
Industrial	O
Standards	O
Committee	O
(	O
JISC	O
)	O
and	O
then	O
to	O
the	O
International	O
Organization	O
for	O
Standardization	O
(	O
ISO	O
)	O
.	O
</s>
<s>
It	O
was	O
accepted	O
as	O
a	O
Japanese	O
Industrial	O
Standard	O
(	O
JIS	O
X	O
3017	O
)	O
in	O
2011	O
and	O
an	O
international	O
standard	O
(	O
ISO/IEC	B-Language
30170	I-Language
)	O
in	O
2012	O
.	O
</s>
<s>
Around	O
2005	O
,	O
interest	O
in	O
the	O
Ruby	B-Language
language	I-Language
surged	O
in	O
tandem	O
with	O
Ruby	B-Application
on	I-Application
Rails	I-Application
,	O
a	O
web	B-Application
framework	I-Application
written	O
in	O
Ruby	B-Language
.	O
</s>
<s>
Rails	O
is	O
frequently	O
credited	O
with	O
increasing	O
awareness	O
of	O
Ruby	B-Language
.	O
</s>
<s>
Effective	O
with	O
Ruby	B-Language
1.9.3	O
,	O
released	O
October	O
31	O
,	O
2011	O
,	O
Ruby	B-Language
switched	O
from	O
being	O
dual-licensed	O
under	O
the	O
Ruby	B-License
License	I-License
and	O
the	O
GPL	O
to	O
being	O
dual-licensed	O
under	O
the	O
Ruby	B-License
License	I-License
and	O
the	O
two-clause	O
BSD	B-Operating_System
license	O
.	O
</s>
<s>
Adoption	O
of	O
1.9	O
was	O
slowed	O
by	O
changes	O
from	O
1.8	O
that	O
required	O
many	O
popular	O
third	O
party	O
gems	B-Application
to	O
be	O
rewritten	O
.	O
</s>
<s>
Ruby	B-Language
1.9	O
introduces	O
many	O
significant	O
changes	O
over	O
the	O
1.8	O
series	O
.	O
</s>
<s>
an	O
additional	O
lambda	B-General_Concept
syntax	O
:	O
</s>
<s>
an	O
additional	O
Hash	B-Algorithm
literal	O
syntax	O
using	O
colons	O
for	O
symbol	O
keys	O
:	O
</s>
<s>
Ruby	B-Language
2.0	O
was	O
intended	O
to	O
be	O
fully	O
backward	O
compatible	O
with	O
Ruby	B-Language
1.9.3	O
.	O
</s>
<s>
Ruby	B-Language
2.0	O
added	O
several	O
new	O
features	O
,	O
including	O
:	O
</s>
<s>
method	B-Language
keyword	O
arguments	O
,	O
</s>
<s>
a	O
new	O
method	B-Language
,	O
Module	B-Architecture
#prepend	O
,	O
for	O
extending	O
a	O
class	B-Application
,	O
</s>
<s>
a	O
new	O
convention	O
of	O
using	O
#to_h	O
to	O
convert	O
objects	O
to	O
Hashes	B-Application
.	O
</s>
<s>
Starting	O
with	O
2.1.0	O
,	O
Ruby	B-Language
's	O
versioning	O
policy	O
changed	O
to	O
be	O
more	O
similar	O
to	O
semantic	O
versioning	O
.	O
</s>
<s>
Ruby	B-Language
2.2.0	O
includes	O
speed-ups	O
,	O
bugfixes	O
,	O
and	O
library	O
updates	O
and	O
removes	O
some	O
deprecated	O
APIs	O
.	O
</s>
<s>
Most	O
notably	O
,	O
Ruby	B-Language
2.2.0	O
introduces	O
changes	O
to	O
memory	O
handling	O
an	O
incremental	O
garbage	B-General_Concept
collector	I-General_Concept
,	O
support	O
for	O
garbage	B-General_Concept
collection	I-General_Concept
of	O
symbols	O
and	O
the	O
option	O
to	O
compile	O
directly	O
against	O
jemalloc	O
.	O
</s>
<s>
Since	O
version	O
2.2.1	O
,	O
Ruby	B-Language
MRI	I-Language
performance	O
on	O
PowerPC64	B-General_Concept
was	O
improved	O
.	O
</s>
<s>
Features	O
that	O
were	O
made	O
obsolete	O
or	O
removed	O
include	O
callcc	O
,	O
the	O
DL	O
library	O
,	O
Digest::HMAC	O
,	O
lib/rational.rb	O
,	O
lib/complex.rb	O
,	O
GServer	O
,	O
Logger::Application	O
as	O
well	O
as	O
various	O
C	B-Language
API	O
functions	O
.	O
</s>
<s>
Ruby	B-Language
2.3.0	O
includes	O
many	O
performance	O
improvements	O
,	O
updates	O
,	O
and	O
bugfixes	O
including	O
changes	O
to	O
Proc	O
#call	O
,	O
Socket	O
and	O
IO	O
use	O
of	O
exception	O
keywords	O
,	O
Thread	B-Operating_System
#name	O
handling	O
,	O
default	O
passive	O
Net::FTP	O
connections	O
,	O
and	O
Rake	O
being	O
removed	O
from	O
stdlib	O
.	O
</s>
<s>
The	O
ability	O
to	O
mark	O
all	O
string	B-Language
literals	I-Language
as	O
frozen	O
by	O
default	O
with	O
a	O
consequently	O
large	O
performance	O
increase	O
in	O
string	O
operations	O
.	O
</s>
<s>
Hash	B-Algorithm
comparison	O
to	O
allow	O
direct	O
checking	O
of	O
key/value	O
pairs	O
instead	O
of	O
just	O
keys	O
.	O
</s>
<s>
The	O
did_you_mean	O
gem	B-Application
is	O
now	O
bundled	O
by	O
default	O
and	O
required	O
on	O
startup	O
to	O
automatically	O
suggest	O
similar	O
name	O
matches	O
on	O
a	O
NameError	O
or	O
NoMethodError	O
.	O
</s>
<s>
Hash	B-Algorithm
#dig	O
and	O
Array	O
#dig	O
to	O
easily	O
extract	O
deeply	O
nested	O
values	O
(	O
e.g.	O
</s>
<s>
.grep_v(regexp )	O
which	O
will	O
match	O
all	O
negative	O
examples	O
of	O
a	O
given	O
regular	B-Language
expression	I-Language
in	O
addition	O
to	O
other	O
new	O
features	O
.	O
</s>
<s>
Ruby	B-Language
2.4.0	O
includes	O
performance	O
improvements	O
to	O
hash	B-Algorithm
table	I-Algorithm
,	O
Array	O
#max	O
,	O
Array	O
#min	O
,	O
and	O
instance	B-Application
variable	I-Application
access	O
.	O
</s>
<s>
A	O
few	O
notable	O
changes	O
in	O
Ruby	B-Language
2.5.0	O
include	O
rescue	O
and	O
ensure	O
statements	O
automatically	O
use	O
a	O
surrounding	O
do-end	O
block	O
(	O
less	O
need	O
for	O
extra	O
begin-end	O
blocks	O
)	O
,	O
method-chaining	O
with	O
yield_self	O
,	O
support	O
for	O
branch	O
coverage	O
and	O
method	B-Language
coverage	O
measurement	O
,	O
and	O
easier	O
Hash	B-Algorithm
transformations	O
with	O
Hash	B-Algorithm
#slice	O
and	O
Hash	B-Algorithm
#transform_keys	O
On	O
top	O
of	O
that	O
come	O
a	O
lot	O
of	O
performance	O
improvements	O
like	O
faster	O
block	O
passing	O
(	O
3	O
times	O
faster	O
)	O
,	O
faster	O
Mutexes	O
,	O
faster	O
ERB	O
templates	O
and	O
improvements	O
on	O
some	O
concatenation	O
methods	O
.	O
</s>
<s>
A	O
few	O
notable	O
changes	O
in	O
Ruby	B-Language
2.6.0	O
include	O
an	O
experimental	O
just-in-time	O
compiler	O
(	O
JIT	O
)	O
,	O
and	O
RubyVM::AbstractSyntaxTree	O
(	O
experimental	O
)	O
.	O
</s>
<s>
A	O
few	O
notable	O
changes	O
in	O
Ruby	B-Language
2.7.0	O
include	O
pattern	O
Matching	O
(	O
experimental	O
)	O
,	O
REPL	B-Application
improvements	O
,	O
a	O
compaction	O
GC	O
,	O
and	O
separation	O
of	O
positional	O
and	O
keyword	O
arguments	O
.	O
</s>
<s>
Ruby	B-Language
3.0.0	O
was	O
released	O
on	O
Christmas	O
Day	O
in	O
2020	O
.	O
</s>
<s>
It	O
is	O
known	O
as	O
Ruby	B-Language
3x3	O
which	O
means	O
that	O
programs	O
would	O
run	O
three	O
times	O
faster	O
in	O
Ruby	B-Language
3.0	O
comparing	O
to	O
Ruby	B-Language
2.0	O
.	O
and	O
some	O
had	O
already	O
implemented	O
in	O
intermediate	O
releases	O
on	O
the	O
road	O
from	O
2	O
to	O
3	O
.	O
</s>
<s>
To	O
achieve	O
3x3	O
,	O
Ruby	B-Language
3	O
comes	O
with	O
MJIT	O
,	O
and	O
later	O
YJIT	O
,	O
Just-In-Time	O
Compilers	O
,	O
to	O
make	O
programs	O
faster	O
,	O
although	O
they	O
are	O
described	O
as	O
experimental	O
and	O
remain	O
disabled	O
by	O
default	O
(	O
enabled	O
by	O
flags	O
at	O
runtime	O
)	O
.	O
</s>
<s>
Another	O
goal	O
of	O
Ruby	B-Language
3.0	O
is	O
to	O
improve	O
concurrency	B-Operating_System
and	O
two	O
more	O
utilities	O
Fibre	B-Operating_System
Scheduler	O
,	O
and	O
experimental	O
Ractor	O
facilitate	O
the	O
goal	O
.	O
</s>
<s>
Ractor	O
is	O
light-weight	O
and	O
thread-safe	O
as	O
it	O
is	O
achieved	O
by	O
exchanging	O
messages	O
rather	O
than	O
shared	O
objects	O
.	O
</s>
<s>
Ruby	B-Language
3.0	O
introduces	O
RBS	O
language	O
to	O
describe	O
the	O
types	O
of	O
Ruby	B-Language
programs	O
for	O
static	O
analysis	O
.	O
</s>
<s>
It	O
is	O
separated	O
from	O
general	O
Ruby	B-Language
programs	O
.	O
</s>
<s>
There	O
are	O
some	O
syntax	O
enhancements	O
and	O
library	O
changes	O
in	O
Ruby	B-Language
3.0	O
as	O
well	O
.	O
</s>
<s>
Ruby	B-Language
3.1	O
was	O
released	O
on	O
Christmas	O
Day	O
in	O
2021	O
.	O
</s>
<s>
A	O
new	O
debugger	B-Application
is	O
also	O
included	O
.	O
</s>
<s>
Network	O
libraries	O
for	O
FTP	B-Protocol
,	O
SMTP	B-Protocol
,	O
IMAP	B-Protocol
,	O
and	O
POP	B-Protocol
are	O
moved	O
from	O
default	O
gems	B-Application
to	O
bundled	O
gems	B-Application
.	O
</s>
<s>
Ruby	B-Language
3.2	O
was	O
released	O
on	O
Christmas	O
Day	O
in	O
2022	O
.	O
</s>
<s>
It	O
brings	O
support	O
for	O
being	O
run	O
inside	O
of	O
a	O
WebAssembly	B-Language
environment	O
via	O
a	O
WASI	O
interface	O
.	O
</s>
<s>
Regular	B-Language
expressions	I-Language
also	O
receives	O
some	O
improvements	O
,	O
including	O
a	O
faster	O
,	O
memoized	O
matching	O
algorithm	O
to	O
protect	O
against	O
certain	O
ReDoS	B-Algorithm
attacks	O
,	O
and	O
configurable	O
timeouts	O
for	O
regular	B-Language
expression	I-Language
matching	O
.	O
</s>
<s>
The	O
MJIT	O
compiler	O
has	O
been	O
re-implemented	O
as	O
a	O
standard	O
library	O
module	B-Architecture
,	O
while	O
the	O
YJIT	O
,	O
a	O
Rust-based	O
JIT	O
compiler	O
now	O
supports	O
more	O
architectures	O
on	O
Linux	B-Application
.	O
</s>
<s>
Matsumoto	O
has	O
said	O
that	O
Ruby	B-Language
is	O
designed	O
for	O
programmer	O
productivity	O
and	O
fun	O
,	O
following	O
the	O
principles	O
of	O
good	O
user	B-Application
interface	I-Application
design	O
.	O
</s>
<s>
At	O
a	O
Google	O
Tech	O
Talk	O
in	O
2008	O
Matsumoto	O
further	O
stated	O
,	O
"	O
I	O
hope	O
to	O
see	O
Ruby	B-Language
help	O
every	O
programmer	O
in	O
the	O
world	O
to	O
be	O
productive	O
,	O
and	O
to	O
enjoy	O
programming	O
,	O
and	O
to	O
be	O
happy	O
.	O
</s>
<s>
He	O
has	O
said	O
that	O
he	O
had	O
not	O
applied	O
the	O
principle	O
of	O
least	O
astonishment	O
(	O
POLA	O
)	O
to	O
the	O
design	O
of	O
Ruby	B-Language
;	O
in	O
a	O
May	O
2005	O
discussion	O
on	O
the	O
newsgroup	B-Application
comp.lang.ruby	O
,	O
Matsumoto	O
attempted	O
to	O
distance	O
Ruby	B-Language
from	O
POLA	O
,	O
explaining	O
that	O
because	O
any	O
design	O
choice	O
will	O
be	O
surprising	O
to	O
someone	O
,	O
he	O
uses	O
a	O
personal	O
standard	O
in	O
evaluating	O
surprise	O
.	O
</s>
<s>
Ruby	B-Language
is	O
object-oriented	B-Language
:	O
every	O
value	O
is	O
an	O
object	O
,	O
including	O
classes	O
and	O
instances	O
of	O
types	O
that	O
many	O
other	O
languages	O
designate	O
as	O
primitives	O
(	O
such	O
as	O
integers	O
,	O
booleans	O
,	O
and	O
"	O
null	O
"	O
)	O
.	O
</s>
<s>
Every	O
function	O
is	O
a	O
method	B-Language
and	O
methods	O
are	O
always	O
called	O
on	O
an	O
object	O
.	O
</s>
<s>
Methods	O
defined	O
at	O
the	O
top	O
level	O
scope	O
become	O
methods	O
of	O
the	O
Object	O
class	B-Application
.	O
</s>
<s>
Since	O
this	O
class	B-Application
is	O
an	O
ancestor	O
of	O
every	O
other	O
class	B-Application
,	O
such	O
methods	O
can	O
be	O
called	O
on	O
any	O
object	O
.	O
</s>
<s>
Ruby	B-Language
supports	O
inheritance	B-Language
with	O
dynamic	O
dispatch	O
,	O
mixins	B-Language
and	O
singleton	O
methods	O
(	O
belonging	O
to	O
,	O
and	O
defined	O
for	O
,	O
a	O
single	O
instance	B-Application
rather	O
than	O
being	O
defined	O
on	O
the	O
class	B-Application
)	O
.	O
</s>
<s>
Though	O
Ruby	B-Language
does	O
not	O
support	O
multiple	B-Application
inheritance	I-Application
,	O
classes	O
can	O
import	O
modules	B-Architecture
as	O
mixins	B-Language
.	O
</s>
<s>
Ruby	B-Language
has	O
been	O
described	O
as	O
a	O
multi-paradigm	O
programming	O
language	O
:	O
it	O
allows	O
procedural	B-Application
programming	I-Application
(	O
defining	O
functions/variables	O
outside	O
classes	O
makes	O
them	O
part	O
of	O
the	O
root	O
,	O
'	O
self	O
 '	O
Object	O
)	O
,	O
with	O
object	O
orientation	O
(	O
everything	O
is	O
an	O
object	O
)	O
or	O
functional	B-Language
programming	I-Language
(	O
it	O
has	O
anonymous	B-General_Concept
functions	I-General_Concept
,	O
closures	B-Language
,	O
and	O
continuations	O
;	O
statements	O
all	O
have	O
values	O
,	O
and	O
functions	O
return	O
the	O
last	O
evaluation	O
)	O
.	O
</s>
<s>
It	O
has	O
support	O
for	O
introspection	B-Application
,	O
reflection	B-Language
and	O
metaprogramming	B-Application
,	O
as	O
well	O
as	O
support	O
for	O
interpreter-based	O
threads	B-Operating_System
.	O
</s>
<s>
Ruby	B-Language
features	O
dynamic	O
typing	O
,	O
and	O
supports	O
parametric	O
polymorphism	O
.	O
</s>
<s>
According	O
to	O
the	O
Ruby	B-Language
FAQ	O
,	O
the	O
syntax	O
is	O
similar	O
to	O
Perl	B-Language
's	O
and	O
the	O
semantics	O
are	O
similar	O
to	O
Smalltalk	B-Application
's	I-Application
,	O
but	O
the	O
design	O
philosophy	O
differs	O
greatly	O
from	O
Python	B-Language
's	I-Language
.	O
</s>
<s>
Support	O
for	O
Unicode	O
and	O
multiple	O
character	B-General_Concept
encodings	I-General_Concept
.	O
</s>
<s>
The	O
syntax	O
of	O
Ruby	B-Language
is	O
broadly	O
similar	O
to	O
that	O
of	O
Perl	B-Language
and	O
Python	B-Language
.	O
</s>
<s>
Class	B-Application
and	O
method	B-Language
definitions	O
are	O
signaled	O
by	O
keywords	O
,	O
whereas	O
code	O
blocks	O
can	O
be	O
defined	O
by	O
either	O
keywords	O
or	O
braces	O
.	O
</s>
<s>
In	O
contrast	O
to	O
Perl	B-Language
,	O
variables	O
are	O
not	O
obligatorily	O
prefixed	O
with	O
a	O
sigil	O
.	O
</s>
<s>
Unlike	O
Python	B-Language
,	O
indentation	O
is	O
not	O
significant	O
.	O
</s>
<s>
One	O
of	O
the	O
differences	O
from	O
Python	B-Language
and	O
Perl	B-Language
is	O
that	O
Ruby	B-Language
keeps	O
all	O
of	O
its	O
instance	B-Application
variables	I-Application
completely	O
private	O
to	O
the	O
class	B-Application
and	O
only	O
exposes	O
them	O
through	O
accessor	O
methods	O
(	O
attr_writer	O
,	O
attr_reader	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
Unlike	O
the	O
"	O
getter	O
"	O
and	O
"	O
setter	O
"	O
methods	O
of	O
other	O
languages	O
like	O
C++	B-Language
or	O
Java	B-Language
,	O
accessor	O
methods	O
in	O
Ruby	B-Language
can	O
be	O
created	O
with	O
a	O
single	O
line	O
of	O
code	O
via	O
metaprogramming	B-Application
;	O
however	O
,	O
accessor	O
methods	O
can	O
also	O
be	O
created	O
in	O
the	O
traditional	O
fashion	O
of	O
C++	B-Language
and	O
Java	B-Language
.	O
</s>
<s>
As	O
invocation	O
of	O
these	O
methods	O
does	O
not	O
require	O
the	O
use	O
of	O
parentheses	O
,	O
it	O
is	O
trivial	O
to	O
change	O
an	O
instance	B-Application
variable	I-Application
into	O
a	O
full	O
function	O
,	O
without	O
modifying	O
a	O
single	O
line	O
of	O
calling	O
code	O
or	O
having	O
to	O
do	O
any	O
refactoring	O
achieving	O
similar	O
functionality	O
to	O
C#	B-Application
and	O
VB.NET	B-Language
property	O
members	O
.	O
</s>
<s>
Python	B-Language
's	I-Language
property	O
descriptors	O
are	O
similar	O
,	O
but	O
come	O
with	O
a	O
trade-off	O
in	O
the	O
development	O
process	O
.	O
</s>
<s>
If	O
one	O
begins	O
in	O
Python	B-Language
by	O
using	O
a	O
publicly	O
exposed	O
instance	B-Application
variable	I-Application
,	O
and	O
later	O
changes	O
the	O
implementation	B-Language
to	O
use	O
a	O
private	O
instance	B-Application
variable	I-Application
exposed	O
through	O
a	O
property	O
descriptor	O
,	O
code	O
internal	O
to	O
the	O
class	B-Application
may	O
need	O
to	O
be	O
adjusted	O
to	O
use	O
the	O
private	O
variable	O
rather	O
than	O
the	O
public	O
property	O
.	O
</s>
<s>
Ruby	B-Language
's	O
design	O
forces	O
all	O
instance	B-Application
variables	I-Application
to	O
be	O
private	O
,	O
but	O
also	O
provides	O
a	O
simple	O
way	O
to	O
declare	O
set	O
and	O
get	O
methods	O
.	O
</s>
<s>
This	O
is	O
in	O
keeping	O
with	O
the	O
idea	O
that	O
in	O
Ruby	B-Language
,	O
one	O
never	O
directly	O
accesses	O
the	O
internal	O
members	O
of	O
a	O
class	B-Application
from	O
outside	O
the	O
class	B-Application
;	O
rather	O
,	O
one	O
passes	O
a	O
message	O
to	O
the	O
class	B-Application
and	O
receives	O
a	O
response	O
.	O
</s>
<s>
The	O
original	O
Ruby	B-Language
interpreter	B-Application
is	O
often	O
referred	O
to	O
as	O
Matz	B-Language
's	I-Language
Ruby	I-Language
Interpreter	I-Language
or	O
MRI	O
.	O
</s>
<s>
This	O
implementation	B-Language
is	O
written	O
in	O
C	B-Language
and	O
uses	O
its	O
own	O
Ruby-specific	O
virtual	B-Architecture
machine	I-Architecture
.	O
</s>
<s>
The	O
standardized	O
and	O
retired	O
Ruby	B-Language
1.8	O
implementation	B-Language
was	O
written	O
in	O
C	B-Language
,	O
as	O
a	O
single-pass	O
interpreted	B-Application
language	I-Application
.	O
</s>
<s>
Starting	O
with	O
Ruby	B-Language
1.9	O
,	O
and	O
continuing	O
with	O
Ruby	B-Language
2.x	O
and	O
above	O
,	O
the	O
official	O
Ruby	B-Language
interpreter	B-Application
has	O
been	O
YARV	B-Language
(	O
"	O
Yet	O
Another	O
Ruby	B-Language
VM	O
"	O
)	O
,	O
and	O
this	O
implementation	B-Language
has	O
superseded	O
the	O
slower	O
virtual	B-Architecture
machine	I-Architecture
used	O
in	O
previous	O
releases	O
of	O
MRI	O
.	O
</s>
<s>
,	O
there	O
are	O
a	O
number	O
of	O
alternative	O
implementations	O
of	O
Ruby	B-Language
,	O
including	O
JRuby	B-Language
,	O
Rubinius	B-Application
,	O
and	O
mruby	B-Application
.	O
</s>
<s>
Each	O
takes	O
a	O
different	O
approach	O
,	O
with	O
JRuby	B-Language
and	O
Rubinius	B-Application
providing	O
just-in-time	O
compilation	O
and	O
mruby	B-Application
also	O
providing	O
ahead-of-time	B-Application
compilation	I-Application
.	O
</s>
<s>
Ruby	B-Language
has	O
three	O
major	O
alternative	O
implementations	O
:	O
</s>
<s>
JRuby	B-Language
,	O
a	O
mixed	O
Java	B-Language
and	O
Ruby	B-Language
implementation	B-Language
that	O
runs	O
on	O
the	O
Java	B-Language
virtual	I-Language
machine	I-Language
.	O
</s>
<s>
JRuby	B-Language
currently	O
targets	O
Ruby	B-Language
3.1.x	O
.	O
</s>
<s>
Rubinius	B-Application
,	O
a	O
C++	B-Language
bytecode	O
virtual	B-Architecture
machine	I-Architecture
that	O
uses	O
LLVM	B-Application
to	O
compile	O
to	O
machine	O
code	O
at	O
runtime	O
.	O
</s>
<s>
The	O
bytecode	O
compiler	O
and	O
most	O
core	O
classes	O
are	O
written	O
in	O
pure	O
Ruby	B-Language
.	O
</s>
<s>
Rubinius	B-Application
currently	O
targets	O
Ruby	B-Language
2.3.1	O
.	O
</s>
<s>
Other	O
Ruby	B-Language
implementations	O
include	O
:	O
</s>
<s>
mruby	B-Application
,	O
an	O
implementation	B-Language
designed	O
to	O
be	O
embedded	O
into	O
C	B-Language
code	O
,	O
in	O
a	O
similar	O
vein	O
to	O
Lua	B-Language
.	O
</s>
<s>
julializer	O
,	O
a	O
transpiler	B-Language
(	O
partial	O
)	O
from	O
Ruby	B-Language
to	O
Julia	B-Application
.	O
</s>
<s>
Ruby	B-Language
or	O
JRuby	B-Language
implementations	O
(	O
may	O
only	O
be	O
useful	O
for	O
numerical	O
code	O
)	O
.	O
</s>
<s>
Other	O
now	O
defunct	O
Ruby	B-Language
implementations	O
were	O
:	O
</s>
<s>
MacRuby	B-Operating_System
,	O
a	O
Mac	B-Application
OS	I-Application
X	I-Application
implementation	B-Language
on	O
the	O
Objective-C	B-Language
runtime	O
.	O
</s>
<s>
The	O
maturity	O
of	O
Ruby	B-Language
implementations	O
tends	O
to	O
be	O
measured	O
by	O
their	O
ability	O
to	O
run	O
the	O
Ruby	B-Application
on	I-Application
Rails	I-Application
(	O
Rails	O
)	O
framework	O
,	O
because	O
it	O
is	O
complex	O
to	O
implement	O
and	O
uses	O
many	O
Ruby-specific	O
features	O
.	O
</s>
<s>
The	O
point	O
when	O
a	O
particular	O
implementation	B-Language
achieves	O
this	O
goal	O
is	O
called	O
"	O
the	O
Rails	O
singularity	O
"	O
.	O
</s>
<s>
The	O
reference	O
implementation	B-Language
,	O
JRuby	B-Language
,	O
and	O
Rubinius	B-Application
are	O
all	O
able	O
to	O
run	O
Rails	O
unmodified	O
in	O
a	O
production	O
environment	O
.	O
</s>
<s>
Matsumoto	O
originally	O
developed	O
Ruby	B-Language
on	O
the	O
4.3BSD-based	O
Sony	B-Operating_System
NEWS-OS	I-Operating_System
3.x	O
,	O
but	O
later	O
migrated	O
his	O
work	O
to	O
SunOS	B-Operating_System
4.x	O
,	O
and	O
finally	O
to	O
Linux	B-Application
.	O
</s>
<s>
By	O
1999	O
,	O
Ruby	B-Language
was	O
known	O
to	O
work	O
across	O
many	O
different	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Modern	O
Ruby	B-Language
versions	O
and	O
implementations	O
are	O
available	O
on	O
all	O
major	O
desktop	O
,	O
mobile	O
and	O
server-based	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Ruby	B-Language
is	O
also	O
supported	O
across	O
a	O
number	O
of	O
cloud	O
hosting	O
platforms	O
like	O
Jelastic	B-General_Concept
,	O
Heroku	B-General_Concept
,	O
Google	B-General_Concept
Cloud	I-General_Concept
Platform	I-General_Concept
and	O
others	O
.	O
</s>
<s>
Tools	O
such	O
as	O
RVM	B-Language
and	O
RBEnv	O
,	O
facilitate	O
installation	O
and	O
partitioning	O
of	O
multiple	O
ruby	B-Language
versions	O
,	O
and	O
multiple	O
'	O
gemsets	O
 '	O
on	O
one	O
machine	O
.	O
</s>
<s>
RubyGems	B-Application
is	O
Ruby	B-Language
's	O
package	O
manager	O
.	O
</s>
<s>
A	O
Ruby	B-Language
package	O
is	O
called	O
a	O
"	O
gem	B-Application
"	O
and	O
can	O
be	O
installed	O
via	O
the	O
command	O
line	O
.	O
</s>
<s>
Most	O
gems	B-Application
are	O
libraries	O
,	O
though	O
a	O
few	O
exist	O
that	O
are	O
applications	O
,	O
such	O
as	O
IDEs	B-Application
.	O
</s>
<s>
There	O
are	O
over	O
100,000	O
Ruby	B-Application
gems	I-Application
hosted	O
on	O
.	O
</s>
<s>
Many	O
new	O
and	O
existing	O
Ruby	B-Language
libraries	O
are	O
hosted	O
on	O
GitHub	B-Application
,	O
a	O
service	O
that	O
offers	O
version	B-Architecture
control	I-Architecture
repository	O
hosting	O
for	O
Git	B-Application
.	O
</s>
<s>
The	O
Ruby	B-Language
Application	O
Archive	O
,	O
which	O
hosted	O
applications	O
,	O
documentation	O
,	O
and	O
libraries	O
for	O
Ruby	B-Language
programming	I-Language
,	O
was	O
maintained	O
until	O
2013	O
,	O
when	O
its	O
function	O
was	O
transferred	O
to	O
RubyGems	B-Application
.	O
</s>
