<s>
Clojure	B-Language
(	O
,	O
like	O
closure	B-Language
)	O
is	O
a	O
dynamic	B-Language
and	O
functional	B-Language
dialect	O
of	O
the	O
Lisp	B-Language
programming	I-Language
language	I-Language
on	O
the	O
Java	B-Device
platform	I-Device
.	O
</s>
<s>
Like	O
most	O
other	O
Lisps	B-Language
,	O
Clojure	B-Language
's	O
syntax	O
is	O
built	O
on	O
S-expressions	B-Protocol
that	O
are	O
first	O
parsed	O
into	O
data	O
structures	O
by	O
a	O
reader	B-Application
before	O
being	O
compiled	O
.	O
</s>
<s>
Clojure	B-Language
's	O
reader	B-Application
supports	O
literal	O
syntax	O
for	O
maps	B-Algorithm
,	O
sets	O
and	O
vectors	B-Data_Structure
along	O
with	O
lists	O
,	O
and	O
these	O
are	O
compiled	O
to	O
the	O
mentioned	O
structures	O
directly	O
.	O
</s>
<s>
Clojure	B-Language
treats	O
code	O
as	O
data	O
and	O
has	O
a	O
Lisp	B-Language
macro	O
system	O
.	O
</s>
<s>
Clojure	B-Language
is	O
a	O
Lisp-1	O
and	O
is	O
not	O
intended	O
to	O
be	O
code-compatible	O
with	O
other	O
dialects	O
of	O
Lisp	B-Language
,	O
since	O
it	O
uses	O
its	O
own	O
set	O
of	O
data	O
structures	O
incompatible	O
with	O
other	O
Lisps	B-Language
.	O
</s>
<s>
Clojure	B-Language
advocates	O
immutability	B-Application
and	O
immutable	B-Application
data	I-Application
structures	I-Application
and	O
encourages	O
programmers	O
to	O
be	O
explicit	O
about	O
managing	O
identity	O
and	O
its	O
states	O
.	O
</s>
<s>
This	O
focus	O
on	O
programming	O
with	O
immutable	B-Application
values	I-Application
and	O
explicit	O
progression-of-time	O
constructs	O
is	O
intended	O
to	O
facilitate	O
developing	O
more	O
robust	O
,	O
especially	O
concurrent	B-Architecture
,	O
programs	O
that	O
are	O
simple	O
and	O
fast	O
.	O
</s>
<s>
While	O
its	O
type	O
system	O
is	O
entirely	O
dynamic	B-Language
,	O
recent	O
efforts	O
have	O
also	O
sought	O
the	O
implementation	O
of	O
a	O
dependent	O
type	O
system	O
.	O
</s>
<s>
The	O
language	O
was	O
created	O
by	O
Rich	O
Hickey	O
in	O
the	O
mid-2000	O
'	O
s	O
,	O
originally	O
for	O
the	O
Java	B-Device
platform	I-Device
;	O
the	O
language	O
has	O
since	O
been	O
ported	O
to	O
other	O
platforms	O
,	O
such	O
as	O
the	O
Common	O
Language	O
Runtime	O
(	O
.NET	B-Application
)	O
.	O
</s>
<s>
Rich	O
Hickey	O
is	O
the	O
creator	O
of	O
the	O
Clojure	B-Language
language	O
.	O
</s>
<s>
Before	O
Clojure	B-Language
,	O
he	O
developed	O
dotLisp	O
,	O
a	O
similar	O
project	O
based	O
on	O
the	O
.NET	B-Application
platform	O
,	O
and	O
three	O
earlier	O
attempts	O
to	O
provide	O
interoperability	O
between	O
Lisp	B-Language
and	O
Java	B-Device
:	O
a	O
Java	B-Device
foreign	O
language	O
interface	O
for	O
Common	B-Language
Lisp	I-Language
(	O
jfli	O
)	O
,	O
A	O
Foreign	O
Object	O
Interface	O
for	O
Lisp	B-Language
(	O
FOIL	O
)	O
,	O
and	O
a	O
Lisp-friendly	O
interface	O
to	O
Java	B-Device
Servlets	O
(	O
Lisplets	O
)	O
.	O
</s>
<s>
Hickey	O
spent	O
about	O
two	O
and	O
a	O
half	O
years	O
working	O
on	O
Clojure	B-Language
before	O
releasing	O
it	O
publicly	O
in	O
October	O
2007	O
,	O
much	O
of	O
that	O
time	O
working	O
exclusively	O
on	O
Clojure	B-Language
with	O
no	O
outside	O
funding	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
this	O
time	O
,	O
Hickey	O
sent	O
an	O
email	O
announcing	O
the	O
language	O
to	O
some	O
friends	O
in	O
the	O
Common	B-Language
Lisp	I-Language
community	O
.	O
</s>
<s>
The	O
development	O
process	O
is	O
restricted	O
to	O
the	O
Clojure	B-Language
core	O
team	O
,	O
though	O
issues	O
are	O
publicly	O
visible	O
at	O
the	O
Clojure	B-Language
JIRA	B-Protocol
project	O
page	O
.	O
</s>
<s>
Anyone	O
can	O
ask	O
questions	O
or	O
submit	O
issues	O
and	O
ideas	O
at	O
ask.clojure.org	O
.	O
</s>
<s>
If	O
it	O
's	O
determined	O
that	O
a	O
new	O
issue	O
warrants	O
a	O
JIRA	B-Protocol
ticket	O
,	O
a	O
core	O
team	O
member	O
will	O
triage	O
it	O
and	O
add	O
it	O
.	O
</s>
<s>
JIRA	B-Protocol
issues	O
are	O
processed	O
by	O
a	O
team	O
of	O
screeners	O
and	O
finally	O
approved	O
by	O
Rich	O
Hickey	O
.	O
</s>
<s>
Clojure	B-Language
's	O
name	O
,	O
according	O
to	O
Hickey	O
,	O
is	O
a	O
word	O
play	O
on	O
the	O
programming	O
concept	O
"	O
closure	B-Language
"	O
incorporating	O
the	O
letters	O
C	O
,	O
L	O
,	O
and	O
J	O
for	O
C#	B-Application
,	O
Lisp	B-Language
,	O
and	O
Java	B-Device
respectively	O
—	O
three	O
languages	O
which	O
had	O
a	O
major	O
influence	O
on	O
Clojure	B-Language
's	O
design	O
.	O
</s>
<s>
Rich	O
Hickey	O
developed	O
Clojure	B-Language
because	O
he	O
wanted	O
a	O
modern	O
Lisp	B-Language
for	O
functional	B-Language
programming	I-Language
,	O
symbiotic	O
with	O
the	O
established	O
Java	B-Device
platform	I-Device
,	O
and	O
designed	O
for	O
concurrency	B-Architecture
.	O
</s>
<s>
Clojure	B-Language
's	O
approach	O
to	O
state	B-Application
is	O
characterized	O
by	O
the	O
concept	O
of	O
identities	O
,	O
which	O
are	O
represented	O
as	O
a	O
series	O
of	O
immutable	B-Application
states	O
over	O
time	O
.	O
</s>
<s>
Since	O
states	O
are	O
immutable	B-Application
values	I-Application
,	O
any	O
number	O
of	O
workers	O
can	O
operate	O
on	O
them	O
in	O
parallel	B-Operating_System
,	O
and	O
concurrency	B-Architecture
becomes	O
a	O
question	O
of	O
managing	O
changes	O
from	O
one	O
state	B-Application
to	O
another	O
.	O
</s>
<s>
For	O
this	O
purpose	O
,	O
Clojure	B-Language
provides	O
several	O
mutable	B-Application
reference	B-Language
types	I-Language
,	O
each	O
having	O
well-defined	O
semantics	O
for	O
the	O
transition	O
between	O
states	O
.	O
</s>
<s>
Version	O
Release	O
date	O
Major	O
features	O
,	O
improvements	O
Initial	O
public	O
release	O
1.0	O
First	O
stable	O
release	O
1.1	O
Futures	O
1.2	O
Protocols	O
1.3	O
Enhanced	O
primitive	O
support	O
1.4	O
Reader	B-Application
literals	O
1.5	O
Reducers	O
1.5.1	O
Fixing	O
a	O
memory	O
leak	O
1.6Java	O
API	O
,	O
improved	O
hashing	O
algorithms	O
1.7	O
Transducers	O
,	O
reader	B-Application
conditionals	O
1.8	O
Additional	O
string	O
functions	O
,	O
direct	O
linking	O
,	O
socket	O
server	O
1.9	O
Integration	O
with	O
spec	O
,	O
command-line	B-Application
tools	I-Application
1.10	O
Improved	O
error	O
reporting	O
,	O
Java	B-Device
compatibility	O
1.10.1	O
Working	O
around	O
a	O
Java	B-Device
performance	O
regression	O
and	O
improving	O
error	O
reporting	O
from	O
clojure.main	O
1.10.2	O
Java	B-Device
interoperability/compatibility	O
improvements	O
and	O
other	O
important	O
language	O
fixes	O
1.10.3	O
prepl	O
support	O
for	O
reader	B-Application
conditionals	O
1.11.0	O
New	O
syntax	O
for	O
keyword	O
argument	O
invocation	O
,	O
new	O
clojure.math	O
namespace	O
,	O
namespace	O
aliasing	O
without	O
loading	O
,	O
and	O
new	O
helper	O
functions	O
added	O
to	O
clojure.core	O
Rolling	O
back	O
unintended	O
change	O
in	O
binary	O
serialisation	O
of	O
objects	O
of	O
types	O
clojure.lang.Keyword	O
and	O
clojure.lang.ArraySeq	O
.	O
</s>
<s>
Clojure	B-Language
runs	O
on	O
the	O
Java	B-Device
platform	I-Device
and	O
as	O
a	O
result	O
,	O
integrates	O
with	O
Java	B-Device
and	O
fully	O
supports	O
calling	O
Java	B-Language
code	I-Language
from	O
Clojure	B-Language
,	O
and	O
Clojure	B-Language
code	O
can	O
be	O
called	O
from	O
Java	B-Device
,	O
too	O
.	O
</s>
<s>
The	O
community	O
uses	O
tools	O
such	O
as	O
Clojure	B-Language
command-line	B-Application
interface	I-Application
(	O
CLI	O
)	O
or	O
Leiningen	B-Application
for	O
project	O
automation	O
,	O
providing	O
support	O
for	O
Maven	B-Language
integration	O
.	O
</s>
<s>
These	O
tools	O
handle	O
project	O
package	O
management	O
and	O
dependencies	O
and	O
are	O
configured	O
using	O
Clojure	B-Language
syntax	O
.	O
</s>
<s>
As	O
a	O
Lisp	B-Language
dialect	O
,	O
Clojure	B-Language
supports	O
functions	O
as	O
first-class	B-Application
objects	I-Application
,	O
a	O
read	B-Application
–	I-Application
eval	I-Application
–	I-Application
print	I-Application
loop	I-Application
(	O
REPL	B-Application
)	O
,	O
and	O
a	O
macro	O
system	O
.	O
</s>
<s>
Clojure	B-Language
's	O
Lisp	B-Language
macro	O
system	O
is	O
very	O
similar	O
to	O
that	O
of	O
Common	B-Language
Lisp	I-Language
with	O
the	O
exception	O
that	O
Clojure	B-Language
's	O
version	O
of	O
the	O
backquote	O
(	O
termed	O
"	O
syntax	O
quote	O
"	O
)	O
qualifies	O
symbols	O
with	O
their	O
namespace	O
.	O
</s>
<s>
Clojure	B-Language
does	O
not	O
allow	O
user-defined	O
reader	B-Application
macros	O
,	O
but	O
the	O
reader	B-Application
supports	O
a	O
more	O
constrained	O
form	O
of	O
syntactic	O
extension	O
.	O
</s>
<s>
Clojure	B-Language
supports	O
multimethods	O
and	O
for	O
interface-like	O
abstractions	O
has	O
a	O
protocol	B-Application
based	O
polymorphism	O
and	O
data	O
type	O
system	O
using	O
records	O
,	O
providing	O
high-performance	O
and	O
dynamic	B-Language
polymorphism	O
designed	O
to	O
avoid	O
the	O
expression	O
problem	O
.	O
</s>
<s>
Clojure	B-Language
has	O
support	O
for	O
lazy	O
sequences	O
and	O
encourages	O
the	O
principle	O
of	O
immutability	B-Application
and	O
persistent	B-Application
data	I-Application
structures	I-Application
.	O
</s>
<s>
As	O
a	O
functional	B-Language
language	I-Language
,	O
emphasis	O
is	O
placed	O
on	O
recursion	O
and	O
higher-order	B-Language
functions	I-Language
instead	O
of	O
side-effect-based	O
looping	O
.	O
</s>
<s>
Automatic	O
tail	B-Language
call	I-Language
optimization	I-Language
is	O
not	O
supported	O
as	O
the	O
JVM	O
does	O
not	O
support	O
it	O
natively	O
;	O
it	O
is	O
possible	O
to	O
do	O
so	O
explicitly	O
by	O
using	O
the	O
recur	O
keyword	O
.	O
</s>
<s>
For	O
parallel	B-Operating_System
and	O
concurrent	B-Architecture
programming	I-Architecture
Clojure	B-Language
provides	O
software	B-Operating_System
transactional	I-Operating_System
memory	I-Operating_System
,	O
a	O
reactive	O
agent	O
system	O
,	O
and	O
channel-based	O
concurrent	B-Architecture
programming	I-Architecture
.	O
</s>
<s>
Clojure	B-Language
1.7	O
introduced	O
reader	B-Application
conditionals	O
by	O
allowing	O
the	O
embedding	O
of	O
Clojure	B-Language
and	O
ClojureScript	B-Language
code	O
in	O
the	O
same	O
namespace	O
.	O
</s>
<s>
Transducers	O
enable	O
higher-order	B-Language
functions	I-Language
such	O
as	O
map	O
and	O
fold	B-Application
to	O
generalize	O
over	O
any	O
source	O
of	O
input	O
data	O
.	O
</s>
<s>
Extensible	O
Data	O
Notation	O
,	O
or	O
edn	O
,	O
is	O
a	O
subset	O
of	O
the	O
Clojure	B-Language
language	O
intended	O
as	O
a	O
data	O
transfer	O
format	O
.	O
</s>
<s>
It	O
can	O
be	O
used	O
to	O
serialize	O
and	O
deserialize	O
Clojure	B-Language
data	O
structures	O
,	O
and	O
Clojure	B-Language
itself	O
uses	O
a	O
superset	O
of	O
edn	O
to	O
represent	O
programs	O
.	O
</s>
<s>
edn	O
is	O
used	O
in	O
a	O
similar	O
way	O
to	O
JSON	B-General_Concept
or	O
XML	B-Protocol
,	O
but	O
has	O
a	O
relatively	O
large	O
list	O
of	O
built-in	O
elements	O
,	O
shown	O
here	O
with	O
examples	O
:	O
</s>
<s>
When	O
encountering	O
a	O
tag	O
,	O
the	O
reader	B-Application
passes	O
the	O
value	O
of	O
the	O
next	O
element	O
to	O
the	O
corresponding	O
handler	O
,	O
which	O
returns	O
a	O
data	O
value	O
.	O
</s>
<s>
For	O
example	O
,	O
this	O
could	O
be	O
a	O
tagged	O
element	O
:	O
#myapp	O
/Person	O
{	O
:	O
first	O
"	O
Fred	O
"	O
:last	O
"	O
Mertz	O
"	O
}	O
,	O
whose	O
interpretation	O
will	O
depend	O
on	O
the	O
appropriate	O
handler	O
of	O
the	O
reader	B-Application
.	O
</s>
<s>
The	O
primary	O
platform	O
of	O
Clojure	B-Language
is	O
Java	B-Device
,	O
but	O
other	O
target	O
implementations	O
exist	O
.	O
</s>
<s>
The	O
most	O
notable	O
of	O
these	O
is	O
ClojureScript	B-Language
,	O
which	O
compiles	O
to	O
ECMAScript	B-Language
3	O
,	O
and	O
ClojureCLR	O
,	O
a	O
full	O
port	O
on	O
the	O
.NET	B-Application
platform	O
,	O
interoperable	O
with	O
its	O
ecosystem	O
.	O
</s>
<s>
A	O
survey	O
of	O
the	O
Clojure	B-Language
community	O
with	O
1,060	O
respondents	O
conducted	O
in	O
2013	O
found	O
that	O
47%	O
of	O
respondents	O
used	O
both	O
Clojure	B-Language
and	O
ClojureScript	B-Language
when	O
working	O
with	O
Clojure	B-Language
.	O
</s>
<s>
Popular	O
ClojureScript	B-Language
projects	O
include	O
implementations	O
of	O
the	O
React	B-Application
library	O
such	O
as	O
Reagent	O
,	O
re-frame	O
,	O
Rum	O
,	O
and	O
Om	O
.	O
</s>
<s>
Other	O
implementations	O
of	O
Clojure	B-Language
on	O
different	O
platforms	O
include	O
:	O
</s>
<s>
ClojureCLR	O
,	O
Clojure	B-Language
on	O
Common	O
Language	O
Runtime	O
(	O
CLR	O
)	O
,	O
the	O
.NET	B-Application
virtual	O
machine	O
.	O
</s>
<s>
ClojureScript	B-Language
,	O
Compiler	O
for	O
.	O
</s>
<s>
With	O
continued	O
interest	O
in	O
functional	B-Language
programming	I-Language
,	O
Clojure	B-Language
's	O
adoption	O
by	O
software	O
developers	O
using	O
the	O
Java	B-Device
platform	I-Device
has	O
continued	O
to	O
increase	O
.	O
</s>
<s>
ThoughtWorks	B-Application
,	O
while	O
assessing	O
functional	B-Language
programming	I-Language
languages	I-Language
for	O
their	O
Technology	O
Radar	O
,	O
described	O
Clojure	B-Language
as	O
"	O
a	O
simple	O
,	O
elegant	O
implementation	O
of	O
Lisp	B-Language
on	O
the	O
JVM	O
"	O
in	O
2010	O
and	O
promoted	O
its	O
status	O
to	O
"	O
ADOPT	O
"	O
in	O
2012	O
.	O
</s>
<s>
In	O
the	O
"	O
JVM	O
Ecosystem	O
Report	O
2018	O
"	O
(	O
which	O
was	O
claimed	O
to	O
be	O
"	O
the	O
largest	O
survey	O
ever	O
of	O
Java	B-Device
developers	O
"	O
)	O
,	O
that	O
was	O
prepared	O
in	O
collaboration	O
by	O
Snyk	O
and	O
Java	B-Device
Magazine	O
,	O
ranked	O
Clojure	B-Language
as	O
the	O
2nd	O
most	O
used	O
programming	O
language	O
on	O
the	O
JVM	O
for	O
"	O
main	O
applications	O
"	O
.	O
</s>
<s>
Clojure	B-Language
is	O
used	O
in	O
industry	O
by	O
firms	O
such	O
as	O
Apple	O
,	O
Atlassian	O
,	O
Funding	O
Circle	O
,	O
Netflix	O
,	O
Nubank	O
,	O
Puppet	B-Application
,	O
and	O
Walmart	O
as	O
well	O
as	O
government	O
agencies	O
such	O
as	O
NASA	O
.	O
</s>
<s>
Tooling	O
for	O
Clojure	B-Language
development	O
has	O
seen	O
significant	O
improvement	O
over	O
the	O
years	O
.	O
</s>
<s>
The	O
following	O
is	O
a	O
list	O
of	O
some	O
popular	O
IDEs	O
and	O
text	B-Application
editors	I-Application
with	O
plug-ins	O
that	O
add	O
support	O
for	O
programming	O
in	O
Clojure	B-Language
:	O
</s>
<s>
Sublime	B-Language
Text	I-Language
,	O
with	O
Clojure	B-Language
Sublimed	O
,	O
or	O
Tutkain	O
,	O
</s>
<s>
In	O
addition	O
to	O
the	O
tools	O
provided	O
by	O
the	O
community	O
,	O
the	O
official	O
Clojure	B-Language
command-line	B-Application
interface	I-Application
(	O
CLI	O
)	O
tools	O
have	O
also	O
become	O
available	O
on	O
Linux	B-Application
,	O
macOS	B-Application
,	O
and	O
Windows	O
since	O
Clojure	B-Language
1.9	O
.	O
</s>
<s>
The	O
following	O
examples	O
can	O
be	O
run	O
in	O
a	O
Clojure	B-Language
REPL	B-Application
such	O
as	O
one	O
started	O
with	O
the	O
Clojure	B-Language
CLI	O
tools	O
or	O
an	O
online	O
REPL	B-Application
such	O
as	O
one	O
available	O
on	O
REPL.it	O
.	O
</s>
<s>
Because	O
of	O
its	O
strong	O
emphasis	O
on	O
simplicity	O
,	O
Clojure	B-Language
programs	O
typically	O
consist	O
of	O
mostly	O
functions	O
and	O
simple	O
data	O
structures	O
(	O
i.e.	O
,	O
lists	O
,	O
vectors	B-Data_Structure
,	O
maps	B-Algorithm
,	O
and	O
sets	O
)	O
:	O
</s>
<s>
Like	O
other	O
Lisps	B-Language
,	O
one	O
of	O
Clojure	B-Language
's	O
iconic	O
features	O
is	O
interactive	O
programming	O
at	O
the	O
REPL	B-Application
.	O
</s>
<s>
Unlike	O
other	O
runtime	O
environments	O
where	O
names	O
get	O
compiled	O
away	O
,	O
Clojure	B-Language
's	O
runtime	O
environment	O
is	O
easily	O
introspectable	O
using	O
normal	O
Clojure	B-Language
data	O
structures	O
:	O
</s>
<s>
Similar	O
to	O
other	O
Lisps	B-Language
,	O
Clojure	B-Language
is	O
homoiconic	O
(	O
also	O
known	O
as	O
"	O
code	O
as	O
data	O
"	O
)	O
.	O
</s>
<s>
A	O
thread-safe	B-Operating_System
generator	O
of	O
unique	O
serial	O
numbers	O
(	O
though	O
,	O
like	O
many	O
other	O
Lisp	B-Language
dialects	O
,	O
Clojure	B-Language
has	O
a	O
built-in	O
gensym	O
function	O
that	O
it	O
uses	O
internally	O
)	O
:	O
</s>
<s>
An	O
anonymous	O
subclass	O
of	O
java.io.Writer	O
that	O
does	O
n't	O
write	O
to	O
anything	O
,	O
and	O
a	O
macro	O
using	O
it	O
to	O
silence	O
all	O
prints	O
within	O
it	O
:	O
</s>
<s>
Clojure	B-Language
was	O
created	O
from	O
the	O
ground	O
up	O
to	O
embrace	O
its	O
host	O
platforms	O
as	O
one	O
of	O
its	O
design	O
goals	O
and	O
thus	O
provides	O
excellent	O
language	B-Language
interoperability	I-Language
with	O
Java	B-Device
:	O
</s>
<s>
10	O
threads	O
manipulating	O
one	O
shared	O
data	O
structure	O
,	O
which	O
consists	O
of	O
100	O
vectors	B-Data_Structure
each	O
one	O
containing	O
10	O
(	O
initially	O
sequential	O
)	O
unique	O
numbers	O
.	O
</s>
<s>
Each	O
thread	O
then	O
repeatedly	O
selects	O
two	O
random	O
positions	O
in	O
two	O
random	O
vectors	B-Data_Structure
and	O
swaps	O
them	O
.	O
</s>
<s>
All	O
changes	O
to	O
the	O
vectors	B-Data_Structure
occur	O
in	O
transactions	O
by	O
making	O
use	O
of	O
Clojure	B-Language
's	O
software	B-Operating_System
transactional	I-Operating_System
memory	I-Operating_System
system	O
:	O
</s>
