<s>
Perl	B-Language
is	O
a	O
family	O
of	O
two	O
high-level	B-Language
,	O
general-purpose	B-Language
,	O
interpreted	B-Application
,	O
dynamic	B-Language
programming	I-Language
languages	I-Language
.	O
</s>
<s>
"	O
Perl	B-Language
"	O
refers	O
to	O
Perl	B-Language
5	O
,	O
but	O
from	O
2000	O
to	O
2019	O
it	O
also	O
referred	O
to	O
its	O
redesigned	O
"	O
sister	O
language	O
"	O
,	O
Perl	B-Application
6	I-Application
,	O
before	O
the	O
latter	O
's	O
name	O
was	O
officially	O
changed	O
to	O
Raku	B-Application
in	O
October	O
2019	O
.	O
</s>
<s>
Though	O
Perl	B-Language
is	O
not	O
officially	O
an	O
acronym	O
,	O
there	O
are	O
various	O
backronyms	O
in	O
use	O
,	O
including	O
"	O
Practical	O
Extraction	B-General_Concept
and	O
Reporting	O
Language	O
"	O
.	O
</s>
<s>
Perl	B-Language
was	O
developed	O
by	O
Larry	O
Wall	O
in	O
1987	O
as	O
a	O
general-purpose	B-Language
Unix	B-Application
scripting	B-Language
language	I-Language
to	O
make	O
report	O
processing	O
easier	O
.	O
</s>
<s>
Raku	B-Application
,	O
which	O
began	O
as	O
a	O
redesign	O
of	O
Perl	B-Language
5	O
in	O
2000	O
,	O
eventually	O
evolved	O
into	O
a	O
separate	O
language	O
.	O
</s>
<s>
The	O
Perl	B-Language
languages	I-Language
borrow	O
features	O
from	O
other	O
programming	O
languages	O
including	O
C	B-Language
,	O
sh	B-Application
,	O
AWK	B-Application
,	O
and	O
sed	B-Application
;	O
They	O
provide	O
text	O
processing	O
facilities	O
without	O
the	O
arbitrary	O
data-length	O
limits	O
of	O
many	O
contemporary	O
Unix	B-Application
command	I-Application
line	I-Application
tools	I-Application
.	O
</s>
<s>
Perl	B-Language
5	O
gained	O
widespread	O
popularity	O
in	O
the	O
late	O
1990s	O
as	O
a	O
CGI	B-Language
scripting	I-Language
language	I-Language
,	O
in	O
part	O
due	O
to	O
its	O
powerful	O
regular	B-Language
expression	I-Language
and	O
string	O
parsing	B-Language
abilities	O
.	O
</s>
<s>
In	O
addition	O
to	O
CGI	B-Language
,	O
Perl	B-Language
5	O
is	O
used	O
for	O
system	B-Application
administration	I-Application
,	O
network	B-Operating_System
programming	I-Operating_System
,	I-Operating_System
finance	O
,	O
bioinformatics	O
,	O
and	O
other	O
applications	O
,	O
such	O
as	O
for	O
GUIs	B-Application
.	O
</s>
<s>
It	O
has	O
been	O
nicknamed	O
"	O
the	O
Swiss	B-Language
Army	I-Language
chainsaw	I-Language
of	O
scripting	B-Language
languages	I-Language
"	O
because	O
of	O
its	O
flexibility	O
and	O
power	O
,	O
and	O
also	O
what	O
some	O
consider	O
ugliness	O
due	O
to	O
its	O
utilization	O
of	O
more	O
special	O
characters	O
than	O
many	O
other	O
languages	O
.	O
</s>
<s>
Perl	B-Language
is	O
a	O
highly	O
expressive	B-Language
programming	O
language	O
:	O
source	O
code	O
for	O
a	O
given	O
algorithm	O
can	O
be	O
short	O
and	O
highly	O
compressible	O
.	O
</s>
<s>
Perl	B-Language
was	O
originally	O
named	O
"	O
Pearl.	O
"	O
</s>
<s>
It	O
is	O
also	O
a	O
Christian	O
reference	O
to	O
the	O
Parable	O
of	O
the	O
Pearl	B-Language
from	O
the	O
Gospel	O
of	O
Matthew	O
.	O
</s>
<s>
However	O
,	O
Wall	O
discovered	O
the	O
existing	O
PEARL	B-Language
programming	I-Language
language	I-Language
before	O
Perl	B-Language
's	O
official	O
release	O
and	O
changed	O
the	O
spelling	O
of	O
the	O
name	O
.	O
</s>
<s>
When	O
referring	O
to	O
the	O
language	O
,	O
the	O
name	O
is	O
capitalized	O
:	O
Perl	B-Language
.	O
</s>
<s>
When	O
referring	O
to	O
the	O
program	O
itself	O
,	O
the	O
name	O
is	O
uncapitalized	O
(	O
perl	B-Language
)	O
because	O
most	O
Unix-like	B-Operating_System
file	O
systems	O
are	O
case-sensitive	O
.	O
</s>
<s>
Before	O
the	O
release	O
of	O
the	O
first	O
edition	O
of	O
Programming	O
Perl	B-Language
,	O
it	O
was	O
common	O
to	O
refer	O
to	O
the	O
language	O
as	O
perl	B-Language
.	O
</s>
<s>
The	O
name	O
is	O
occasionally	O
expanded	O
as	O
a	O
backronym	O
:	O
Practical	B-Language
Extraction	I-Language
and	I-Language
Report	I-Language
Language	I-Language
and	O
Wall	O
's	O
own	O
Pathologically	B-Language
Eclectic	I-Language
Rubbish	I-Language
Lister	I-Language
which	O
is	O
in	O
the	O
manual	B-Protocol
page	I-Protocol
for	O
perl	B-Language
.	O
</s>
<s>
Larry	O
Wall	O
began	O
work	O
on	O
Perl	B-Language
in	O
1987	O
,	O
while	O
employed	O
as	O
a	O
programmer	O
at	O
Unisys	O
;	O
he	O
released	O
version	O
1.0	O
on	O
December	O
18	O
,	O
1987	O
.	O
</s>
<s>
Perl	B-Language
2	O
,	O
released	O
in	O
June	O
1988	O
,	O
featured	O
a	O
better	O
regular	B-Language
expression	I-Language
engine	O
.	O
</s>
<s>
Perl	B-Language
3	O
,	O
released	O
in	O
October	O
1989	O
,	O
added	O
support	O
for	O
binary	O
data	O
streams	O
.	O
</s>
<s>
Originally	O
,	O
the	O
only	O
documentation	O
for	O
Perl	B-Language
was	O
a	O
single	O
lengthy	O
main	B-Protocol
page	I-Protocol
.	O
</s>
<s>
In	O
1991	O
,	O
Programming	O
Perl	B-Language
,	O
known	O
to	O
many	O
Perl	B-Language
programmers	O
as	O
the	O
"	O
Camel	O
Book	O
"	O
because	O
of	O
its	O
cover	O
,	O
was	O
published	O
and	O
became	O
the	O
de	O
facto	O
reference	O
for	O
the	O
language	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
the	O
Perl	B-Language
version	O
number	O
was	O
bumped	O
to	O
4	O
,	O
not	O
to	O
mark	O
a	O
major	O
change	O
in	O
the	O
language	O
but	O
to	O
identify	O
the	O
version	O
that	O
was	O
well	O
documented	O
by	O
the	O
book	O
.	O
</s>
<s>
Perl	B-Language
4	O
was	O
released	O
in	O
March	O
1991	O
.	O
</s>
<s>
Perl	B-Language
4	O
went	O
through	O
a	O
series	O
of	O
maintenance	B-General_Concept
releases	I-General_Concept
,	O
culminating	O
in	O
Perl	B-Language
4.036	O
in	O
1993	O
,	O
whereupon	O
Wall	O
abandoned	O
Perl	B-Language
4	O
to	O
begin	O
work	O
on	O
Perl	B-Language
5	O
.	O
</s>
<s>
Initial	O
design	O
of	O
Perl	B-Language
5	O
continued	O
into	O
1994	O
.	O
</s>
<s>
The	O
perl5-porters	O
mailing	O
list	O
was	O
established	O
in	O
May	O
1994	O
to	O
coordinate	O
work	O
on	O
porting	O
Perl	B-Language
5	O
to	O
different	O
platforms	O
.	O
</s>
<s>
It	O
remains	O
the	O
primary	O
forum	O
for	O
development	O
,	O
maintenance	O
,	O
and	O
porting	O
of	O
Perl	B-Language
5	O
.	O
</s>
<s>
Perl	B-Language
5.000	O
was	O
released	O
on	O
October	O
17	O
,	O
1994	O
.	O
</s>
<s>
It	O
was	O
a	O
nearly	O
complete	O
rewrite	O
of	O
the	O
interpreter	B-Application
,	O
and	O
it	O
added	O
many	O
new	O
features	O
to	O
the	O
language	O
,	O
including	O
objects	O
,	O
references	O
,	O
lexical	O
(	O
my	O
)	O
variables	O
,	O
and	O
modules	B-Language
.	O
</s>
<s>
Importantly	O
,	O
modules	B-Language
provided	O
a	O
mechanism	O
for	O
extending	O
the	O
language	O
without	O
modifying	O
the	O
interpreter	B-Application
.	O
</s>
<s>
This	O
allowed	O
the	O
core	O
interpreter	B-Application
to	O
stabilize	O
,	O
even	O
as	O
it	O
enabled	O
ordinary	O
Perl	B-Language
programmers	O
to	O
add	O
new	O
language	O
features	O
.	O
</s>
<s>
Perl	B-Language
5	O
has	O
been	O
in	O
active	O
development	O
since	O
then	O
.	O
</s>
<s>
Perl	B-Language
5.001	O
was	O
released	O
on	O
March	O
13	O
,	O
1995	O
.	O
</s>
<s>
Perl	B-Language
5.002	O
was	O
released	O
on	O
February	O
29	O
,	O
1996	O
with	O
the	O
new	O
prototypes	O
feature	O
.	O
</s>
<s>
This	O
allowed	O
module	B-Language
authors	O
to	O
make	O
subroutines	O
that	O
behaved	O
like	O
Perl	B-Language
builtins	O
.	O
</s>
<s>
Perl	B-Language
5.003	O
was	O
released	O
June	O
25	O
,	O
1996	O
,	O
as	O
a	O
security	O
release	O
.	O
</s>
<s>
One	O
of	O
the	O
most	O
important	O
events	O
in	O
Perl	B-Language
5	O
history	O
took	O
place	O
outside	O
of	O
the	O
language	O
proper	O
and	O
was	O
a	O
consequence	O
of	O
its	O
module	B-Language
support	O
.	O
</s>
<s>
On	O
October	O
26	O
,	O
1995	O
,	O
the	O
Comprehensive	B-Language
Perl	I-Language
Archive	I-Language
Network	I-Language
(	O
CPAN	B-Language
)	O
was	O
established	O
as	O
a	O
repository	B-Application
for	O
the	O
Perl	B-Language
language	I-Language
and	O
Perl	B-Language
modules	I-Language
;	O
as	O
of	O
December	O
2022	O
,	O
it	O
carries	O
over	O
211,850	O
modules	B-Language
in	O
43,865	O
distributions	O
,	O
written	O
by	O
more	O
than	O
14,324	O
authors	O
,	O
and	O
is	O
mirrored	O
worldwide	O
at	O
more	O
than	O
245	O
locations	O
.	O
</s>
<s>
Perl	B-Language
5.004	O
was	O
released	O
on	O
May	O
15	O
,	O
1997	O
,	O
and	O
included	O
,	O
among	O
other	O
things	O
,	O
the	O
UNIVERSAL	O
package	O
,	O
giving	O
Perl	B-Language
a	O
base	O
object	O
from	O
which	O
all	O
classes	O
were	O
automatically	O
derived	O
and	O
the	O
ability	O
to	O
require	O
versions	O
of	O
modules	B-Language
.	O
</s>
<s>
Another	O
significant	O
development	O
was	O
the	O
inclusion	O
of	O
the	O
CGI.pm	B-Language
module	B-Language
,	O
which	O
contributed	O
to	O
Perl	B-Language
's	O
popularity	O
as	O
a	O
CGI	B-Language
scripting	I-Language
language	I-Language
.	O
</s>
<s>
Perl	B-Language
5.004	O
added	O
support	O
for	O
Microsoft	B-Application
Windows	I-Application
,	O
Plan	B-Operating_System
9	I-Operating_System
,	O
QNX	B-Operating_System
,	O
and	O
AmigaOS	B-Application
.	O
</s>
<s>
Perl	B-Language
5.005	O
was	O
released	O
on	O
July	O
22	O
,	O
1998	O
.	O
</s>
<s>
This	O
release	O
included	O
several	O
enhancements	O
to	O
the	O
regex	B-Language
engine	O
,	O
new	O
hooks	O
into	O
the	O
backend	O
through	O
the	O
B::*	O
modules	B-Language
,	O
the	O
qr//	O
regex	B-Language
quote	O
operator	O
,	O
a	O
large	O
selection	O
of	O
other	O
new	O
core	O
modules	B-Language
,	O
and	O
added	O
support	O
for	O
several	O
more	O
operating	B-General_Concept
systems	I-General_Concept
,	O
including	O
BeOS	B-Application
.	O
</s>
<s>
Perl	B-Language
5.6	O
was	O
released	O
on	O
March	O
22	O
,	O
2000	O
.	O
</s>
<s>
Major	O
changes	O
included	O
64-bit	B-Device
support	I-Device
,	O
Unicode	O
string	O
representation	O
,	O
support	O
for	O
files	O
over	O
2	O
GiB	O
,	O
and	O
the	O
"	O
our	O
"	O
keyword	O
.	O
</s>
<s>
When	O
developing	O
Perl	B-Language
5.6	O
,	O
the	O
decision	O
was	O
made	O
to	O
switch	O
the	O
versioning	O
scheme	O
to	O
one	O
more	O
similar	O
to	O
other	O
open	O
source	O
projects	O
;	O
after	O
5.005_63	O
,	O
the	O
next	O
version	O
became	O
5.5.640	O
,	O
with	O
plans	O
for	O
development	O
versions	O
to	O
have	O
odd	O
numbers	O
and	O
stable	O
versions	O
to	O
have	O
even	O
numbers	O
.	O
</s>
<s>
In	O
2000	O
,	O
Wall	O
put	O
forth	O
a	O
call	O
for	O
suggestions	O
for	O
a	O
new	O
version	O
of	O
Perl	B-Language
from	O
the	O
community	O
.	O
</s>
<s>
The	O
process	O
resulted	O
in	O
361	O
RFC	O
(	O
request	O
for	O
comments	O
)	O
documents	O
that	O
were	O
to	O
be	O
used	O
in	O
guiding	O
development	O
of	O
Perl	B-Application
6	I-Application
.	O
</s>
<s>
In	O
2001	O
,	O
work	O
began	O
on	O
the	O
"	O
Apocalypses	O
"	O
for	O
Perl	B-Application
6	I-Application
,	O
a	O
series	O
of	O
documents	O
meant	O
to	O
summarize	O
the	O
change	O
requests	O
and	O
present	O
the	O
design	O
of	O
the	O
next	O
generation	O
of	O
Perl	B-Language
.	O
</s>
<s>
At	O
this	O
point	O
,	O
Perl	B-Application
6	I-Application
existed	O
only	O
as	O
a	O
description	O
of	O
a	O
language	O
.	O
</s>
<s>
Perl	B-Language
5.8	O
was	O
first	O
released	O
on	O
July	O
18	O
,	O
2002	O
,	O
and	O
had	O
nearly	O
yearly	O
updates	O
since	O
then	O
.	O
</s>
<s>
Perl	B-Language
5.8	O
improved	O
Unicode	O
support	O
,	O
added	O
a	O
new	O
I/O	O
implementation	O
,	O
added	O
a	O
new	O
thread	O
implementation	O
,	O
improved	O
numeric	O
accuracy	O
,	O
and	O
added	O
several	O
new	O
modules	B-Language
.	O
</s>
<s>
In	O
2004	O
,	O
work	O
began	O
on	O
the	O
"	O
Synopses	O
"	O
documents	O
that	O
originally	O
summarized	O
the	O
Apocalypses	O
,	O
but	O
which	O
became	O
the	O
specification	B-Application
for	O
the	O
Perl	B-Application
6	I-Application
language	O
.	O
</s>
<s>
In	O
February	O
2005	O
,	O
Audrey	O
Tang	O
began	O
work	O
on	O
Pugs	B-Language
,	O
a	O
Perl	B-Application
6	I-Application
interpreter	B-Application
written	O
in	O
Haskell	B-Language
.	O
</s>
<s>
This	O
was	O
the	O
first	O
concerted	O
effort	O
toward	O
making	O
Perl	B-Application
6	I-Application
a	O
reality	O
.	O
</s>
<s>
PONIE	B-Language
is	O
an	O
acronym	O
for	O
Perl	B-Language
On	O
New	O
Internal	O
Engine	O
.	O
</s>
<s>
The	O
PONIE	B-Language
Project	O
existed	O
from	O
2003	O
until	O
2006	O
and	O
was	O
to	O
be	O
a	O
bridge	O
between	O
Perl	B-Language
5	O
and	O
Perl	B-Application
6	I-Application
.	O
</s>
<s>
It	O
was	O
an	O
effort	O
to	O
rewrite	O
the	O
Perl	B-Language
5	O
interpreter	B-Application
to	O
run	O
on	O
Parrot	B-Language
,	O
the	O
Perl	B-Application
6	I-Application
virtual	B-Architecture
machine	I-Architecture
.	O
</s>
<s>
The	O
goal	O
was	O
to	O
ensure	O
the	O
future	O
of	O
the	O
millions	O
of	O
lines	O
of	O
Perl	B-Language
5	O
code	O
at	O
thousands	O
of	O
companies	O
around	O
the	O
world	O
.	O
</s>
<s>
The	O
PONIE	B-Language
project	O
ended	O
in	O
2006	O
and	O
is	O
no	O
longer	O
being	O
actively	O
developed	O
.	O
</s>
<s>
Some	O
of	O
the	O
improvements	O
made	O
to	O
the	O
Perl	B-Language
5	O
interpreter	B-Application
as	O
part	O
of	O
PONIE	B-Language
were	O
folded	O
into	O
that	O
project	O
.	O
</s>
<s>
On	O
December	O
18	O
,	O
2007	O
,	O
the	O
20th	O
anniversary	O
of	O
Perl	B-Language
1.0	O
,	O
Perl	B-Language
5.10.0	O
was	O
released	O
.	O
</s>
<s>
Perl	B-Language
5.10.0	O
included	O
notable	O
new	O
features	O
,	O
which	O
brought	O
it	O
closer	O
to	O
Perl	B-Application
6	I-Application
.	O
</s>
<s>
These	O
included	O
a	O
switch	O
statement	O
(	O
called	O
"	O
given	O
"	O
/	O
"	O
when	O
"	O
)	O
,	O
regular	B-Language
expressions	I-Language
updates	O
,	O
and	O
the	O
smart	O
match	O
operator	O
(~~	O
)	O
.	O
</s>
<s>
Around	O
this	O
same	O
time	O
,	O
development	O
began	O
in	O
earnest	O
on	O
another	O
implementation	O
of	O
Perl	B-Application
6	I-Application
known	O
as	O
Rakudo	B-Language
Perl	I-Language
,	O
developed	O
in	O
tandem	O
with	O
the	O
Parrot	B-Language
virtual	I-Language
machine	I-Language
.	O
</s>
<s>
As	O
of	O
November	O
2009	O
,	O
Rakudo	B-Language
Perl	I-Language
has	O
had	O
regular	O
monthly	O
releases	O
and	O
now	O
is	O
the	O
most	O
complete	O
implementation	O
of	O
Perl	B-Application
6	I-Application
.	O
</s>
<s>
A	O
major	O
change	O
in	O
the	O
development	O
process	O
of	O
Perl	B-Language
5	O
occurred	O
with	O
Perl	B-Language
5.11	O
;	O
the	O
development	O
community	O
has	O
switched	O
to	O
a	O
monthly	O
release	O
cycle	O
of	O
development	O
releases	O
,	O
with	O
a	O
yearly	O
schedule	O
of	O
stable	O
releases	O
.	O
</s>
<s>
On	O
April	O
12	O
,	O
2010	O
,	O
Perl	B-Language
5.12.0	O
was	O
released	O
.	O
</s>
<s>
Notable	O
core	O
enhancements	O
include	O
new	O
package	O
NAME	O
VERSION	O
syntax	O
,	O
the	O
yada	O
yada	O
operator	O
(	O
intended	O
to	O
mark	O
placeholder	O
code	O
that	O
is	O
not	O
yet	O
implemented	O
)	O
,	O
implicit	O
strictures	O
,	O
full	O
Y2038	B-Application
compliance	O
,	O
regex	B-Language
conversion	O
overloading	O
,	O
DTrace	B-Application
support	O
,	O
and	O
Unicode	O
5.2	O
.	O
</s>
<s>
On	O
May	O
14	O
,	O
2011	O
,	O
Perl	B-Language
5.14	O
was	O
released	O
with	O
JSON	B-General_Concept
support	O
built-in	O
.	O
</s>
<s>
On	O
May	O
20	O
,	O
2012	O
,	O
Perl	B-Language
5.16	O
was	O
released	O
.	O
</s>
<s>
Notable	O
new	O
features	O
include	O
the	O
ability	O
to	O
specify	O
a	O
given	O
version	O
of	O
Perl	B-Language
that	O
one	O
wishes	O
to	O
emulate	O
,	O
allowing	O
users	O
to	O
upgrade	O
their	O
version	O
of	O
Perl	B-Language
,	O
but	O
still	O
run	O
old	O
scripts	O
that	O
would	O
normally	O
be	O
incompatible	O
.	O
</s>
<s>
Perl	B-Language
5.16	O
also	O
updates	O
the	O
core	O
to	O
support	O
Unicode	O
6.1	O
.	O
</s>
<s>
On	O
May	O
18	O
,	O
2013	O
,	O
Perl	B-Language
5.18	O
was	O
released	O
.	O
</s>
<s>
Notable	O
new	O
features	O
include	O
the	O
new	O
dtrace	B-Application
hooks	O
,	O
lexical	O
subs	O
,	O
more	O
CORE::	O
subs	O
,	O
overhaul	O
of	O
the	O
hash	O
for	O
security	O
reasons	O
,	O
support	O
for	O
Unicode	O
6.2	O
.	O
</s>
<s>
On	O
May	O
27	O
,	O
2014	O
,	O
Perl	B-Language
5.20	O
was	O
released	O
.	O
</s>
<s>
Some	O
observers	O
credit	O
the	O
release	O
of	O
Perl	B-Language
5.10	O
with	O
the	O
start	O
of	O
the	O
Modern	O
Perl	B-Language
movement	O
.	O
</s>
<s>
In	O
particular	O
,	O
this	O
phrase	O
describes	O
a	O
style	O
of	O
development	O
that	O
embraces	O
the	O
use	O
of	O
the	O
CPAN	B-Language
,	O
takes	O
advantage	O
of	O
recent	O
developments	O
in	O
the	O
language	O
,	O
and	O
is	O
rigorous	O
about	O
creating	O
high	O
quality	O
code	O
.	O
</s>
<s>
While	O
the	O
book	O
"	O
Modern	O
Perl	B-Language
"	O
may	O
be	O
the	O
most	O
visible	O
standard-bearer	O
of	O
this	O
idea	O
,	O
other	O
groups	O
such	O
as	O
the	O
Enlightened	O
Perl	B-Language
Organization	O
have	O
taken	O
up	O
the	O
cause	O
.	O
</s>
<s>
In	O
late	O
2012	O
and	O
2013	O
,	O
several	O
projects	O
for	O
alternative	O
implementations	O
for	O
Perl	B-Language
5	O
started	O
:	O
Perl5	B-Language
in	O
Perl6	B-Application
by	O
the	O
Rakudo	B-Language
Perl	I-Language
team	O
,	O
by	O
Stevan	O
Little	O
and	O
friends	O
,	O
by	O
the	O
Perl11	O
team	O
under	O
Reini	O
Urban	O
,	O
by	O
,	O
and	O
,	O
a	O
Kickstarter	O
project	O
led	O
by	O
Will	O
Braswell	O
and	O
affiliated	O
with	O
the	O
Perll11	O
project	O
.	O
</s>
<s>
In	O
June	O
2020	O
,	O
Perl	B-Language
7	O
was	O
announced	O
as	O
the	O
successor	O
to	O
Perl	B-Language
5	O
.	O
</s>
<s>
Perl	B-Language
7	O
was	O
to	O
initially	O
be	O
based	O
on	O
Perl	B-Language
5.32	O
with	O
a	O
release	O
expected	O
in	O
first	O
half	O
of	O
2021	O
,	O
and	O
release	O
candidates	O
sooner	O
.	O
</s>
<s>
This	O
plan	O
was	O
revised	O
in	O
May	O
2021	O
,	O
without	O
any	O
release	O
timeframe	O
or	O
version	O
of	O
Perl	B-Language
5	O
for	O
use	O
as	O
a	O
baseline	O
specified	O
.	O
</s>
<s>
When	O
Perl	B-Language
7	O
is	O
released	O
,	O
Perl	B-Language
5	O
will	O
go	O
into	O
long	O
term	O
maintenance	O
.	O
</s>
<s>
Supported	O
Perl	B-Language
5	O
versions	O
however	O
will	O
continue	O
to	O
get	O
important	O
security	O
and	O
bug	B-Error_Name
fixes	O
.	O
</s>
<s>
Programming	O
Perl	B-Language
,	O
published	O
by	O
O'Reilly	O
Media	O
,	O
features	O
a	O
picture	O
of	O
a	O
dromedary	O
camel	O
on	O
the	O
cover	O
and	O
is	O
commonly	O
called	O
the	O
"	O
Camel	O
Book	O
"	O
.	O
</s>
<s>
This	O
image	O
has	O
become	O
an	O
unofficial	O
symbol	O
of	O
Perl	B-Language
as	O
well	O
as	O
a	O
general	O
hacker	O
emblem	O
,	O
appearing	O
on	O
T-shirts	O
and	O
other	O
clothing	O
items	O
.	O
</s>
<s>
O'Reilly	O
owns	O
the	O
image	O
as	O
a	O
trademark	O
but	O
licenses	O
it	O
for	O
non-commercial	O
use	O
,	O
requiring	O
only	O
an	O
acknowledgement	O
and	O
a	O
link	O
to	O
www.perl.com	O
.	O
</s>
<s>
O'Reilly	O
also	O
provides	O
"	O
Programming	O
Republic	O
of	O
Perl	B-Language
"	O
logos	O
for	O
non-commercial	O
sites	O
and	O
"	O
Powered	O
by	O
Perl	B-Language
"	O
buttons	O
for	O
any	O
site	O
that	O
uses	O
Perl	B-Language
.	O
</s>
<s>
The	B-Language
Perl	I-Language
Foundation	I-Language
owns	O
an	O
alternative	O
symbol	O
,	O
an	O
onion	O
,	O
which	O
it	O
licenses	O
to	O
its	O
subsidiaries	O
,	O
Perl	B-Language
Mongers	I-Language
,	O
PerlMonks	B-Language
,	O
Perl.org,	O
and	O
others	O
.	O
</s>
<s>
The	O
symbol	O
is	O
a	O
visual	O
pun	O
on	O
pearl	B-Language
onion	O
.	O
</s>
<s>
Sebastian	O
Riedel	O
,	O
the	O
creator	O
of	O
Mojolicious	B-Language
,	O
created	O
a	O
logo	O
depicting	O
a	O
raptor	O
dinosaur	O
,	O
which	O
is	O
available	O
under	O
a	O
CC-SA	O
License	O
,	O
Version	O
4.0	O
.	O
</s>
<s>
According	O
to	O
Wall	O
,	O
Perl	B-Language
has	O
two	O
slogans	O
.	O
</s>
<s>
The	O
first	O
is	O
"	O
There	B-Architecture
's	I-Architecture
more	I-Architecture
than	I-Architecture
one	I-Architecture
way	I-Architecture
to	I-Architecture
do	I-Architecture
it	I-Architecture
,	O
"	O
commonly	O
known	O
as	O
TMTOWTDI	B-Architecture
,	O
(	O
pronounced	O
Tim	B-Architecture
Toady	I-Architecture
)	O
.	O
</s>
<s>
The	O
overall	O
structure	O
of	O
Perl	B-Language
derives	O
broadly	O
from	O
C	B-Language
.	O
Perl	B-Language
is	O
procedural	B-Application
in	O
nature	O
,	O
with	O
variables	O
,	O
expressions	O
,	O
assignment	O
statements	O
,	O
brace-delimited	O
blocks	O
,	O
control	O
structures	O
,	O
and	O
subroutines	O
.	O
</s>
<s>
Perl	B-Language
also	O
takes	O
features	O
from	O
shell	O
programming	O
.	O
</s>
<s>
However	O
,	O
unlike	O
the	O
shell	O
,	O
Perl	B-Language
uses	O
sigils	O
on	O
all	O
accesses	O
to	O
variables	O
,	O
and	O
unlike	O
most	O
other	O
programming	O
languages	O
that	O
use	O
sigils	O
,	O
the	O
sigil	O
does	O
n't	O
denote	O
the	O
type	O
of	O
the	O
variable	O
but	O
the	O
type	O
of	O
the	O
expression	O
.	O
</s>
<s>
Perl	B-Language
also	O
has	O
many	O
built-in	O
functions	O
that	O
provide	O
tools	O
often	O
used	O
in	O
shell	O
programming	O
(	O
although	O
many	O
of	O
these	O
tools	O
are	O
implemented	O
by	O
programs	O
external	O
to	O
the	O
shell	O
)	O
such	O
as	O
sorting	O
,	O
and	O
calling	O
operating	B-General_Concept
system	I-General_Concept
facilities	O
.	O
</s>
<s>
Perl	B-Language
takes	O
hashes	B-Application
(	O
"	O
associative	B-Application
arrays	I-Application
"	O
)	O
from	O
AWK	B-Application
and	O
regular	B-Language
expressions	I-Language
from	O
sed	B-Application
.	O
</s>
<s>
These	O
simplify	O
many	O
parsing	B-Language
,	O
text-handling	O
,	O
and	O
data-management	O
tasks	O
.	O
</s>
<s>
Shared	O
with	O
Lisp	B-Language
is	O
the	O
implicit	O
return	B-Language
of	O
the	O
last	O
value	O
in	O
a	O
block	O
,	O
and	O
all	O
statements	O
are	O
also	O
expressions	O
which	O
can	O
be	O
used	O
in	O
larger	O
expressions	O
themselves	O
.	O
</s>
<s>
Perl	B-Language
5	O
added	O
features	O
that	O
support	O
complex	O
data	B-General_Concept
structures	I-General_Concept
,	O
first-class	B-Application
functions	I-Application
(	O
that	O
is	O
,	O
closures	B-Language
as	O
values	O
)	O
,	O
and	O
an	O
object-oriented	B-Language
programming	I-Language
model	O
.	O
</s>
<s>
These	O
include	O
references	O
,	O
packages	O
,	O
class-based	B-Application
method	O
dispatch	O
,	O
and	O
lexically	B-Language
scoped	I-Language
variables	I-Language
,	O
along	O
with	O
compiler	B-Language
directives	O
(	O
for	O
example	O
,	O
the	O
strict	O
pragma	O
)	O
.	O
</s>
<s>
A	O
major	O
additional	O
feature	O
introduced	O
with	O
Perl	B-Language
5	O
was	O
the	O
ability	O
to	O
package	O
code	O
as	O
reusable	O
modules	B-Language
.	O
</s>
<s>
Wall	O
later	O
stated	O
that	O
"	O
The	O
whole	O
intent	O
of	O
Perl	B-Language
5	O
's	O
module	B-Architecture
system	I-Architecture
was	O
to	O
encourage	O
the	O
growth	O
of	O
Perl	B-Language
culture	O
rather	O
than	O
the	O
Perl	B-Language
core.	O
"	O
</s>
<s>
All	O
versions	O
of	O
Perl	B-Language
do	O
automatic	O
data-typing	O
and	O
automatic	O
memory	B-General_Concept
management	I-General_Concept
.	O
</s>
<s>
The	O
interpreter	B-Application
knows	O
the	O
type	O
and	O
storage	B-General_Concept
requirements	O
of	O
every	O
data	O
object	O
in	O
the	O
program	O
;	O
it	O
allocates	O
and	O
frees	O
storage	B-General_Concept
for	O
them	O
as	O
necessary	O
using	O
reference	B-General_Concept
counting	I-General_Concept
(	O
so	O
it	O
cannot	O
deallocate	O
circular	B-Language
data	I-Language
structures	I-Language
without	O
manual	O
intervention	O
)	O
.	O
</s>
<s>
Legal	O
type	O
conversions	O
—	O
for	O
example	O
,	O
conversions	O
from	O
number	O
to	O
string	O
—	O
are	O
done	O
automatically	O
at	O
run	B-Library
time	I-Library
;	O
illegal	O
type	O
conversions	O
are	O
fatal	O
errors	O
.	O
</s>
<s>
The	O
design	O
of	O
Perl	B-Language
can	O
be	O
understood	O
as	O
a	O
response	O
to	O
three	O
broad	O
trends	O
in	O
the	O
computer	O
industry	O
:	O
falling	O
hardware	O
costs	O
,	O
rising	O
labor	O
costs	O
,	O
and	O
improvements	O
in	O
compiler	B-Language
technology	O
.	O
</s>
<s>
Many	O
earlier	O
computer	O
languages	O
,	O
such	O
as	O
Fortran	B-Application
and	O
C	B-Language
,	O
aimed	O
to	O
make	O
efficient	O
use	O
of	O
expensive	O
computer	O
hardware	O
.	O
</s>
<s>
In	O
contrast	O
,	O
Perl	B-Language
was	O
designed	O
so	O
that	O
computer	O
programmers	O
could	O
write	O
programs	O
more	O
quickly	O
and	O
easily	O
.	O
</s>
<s>
Perl	B-Language
has	O
many	O
features	O
that	O
ease	O
the	O
task	O
of	O
the	O
programmer	O
at	O
the	O
expense	O
of	O
greater	O
CPU	B-Device
and	O
memory	O
requirements	O
.	O
</s>
<s>
These	O
include	O
automatic	O
memory	B-General_Concept
management	I-General_Concept
;	O
dynamic	O
typing	O
;	O
strings	O
,	O
lists	O
,	O
and	O
hashes	B-Application
;	O
regular	B-Language
expressions	I-Language
;	O
introspection	B-Application
;	O
and	O
an	O
eval( )	O
function	O
.	O
</s>
<s>
Perl	B-Language
follows	O
the	O
theory	O
of	O
"	O
no	O
built-in	O
limits	O
,	O
"	O
an	O
idea	O
similar	O
to	O
the	O
Zero	O
One	O
Infinity	B-Application
rule	O
.	O
</s>
<s>
Wall	O
was	O
trained	O
as	O
a	O
linguist	O
,	O
and	O
the	O
design	O
of	O
Perl	B-Language
is	O
very	O
much	O
informed	O
by	O
linguistic	O
principles	O
.	O
</s>
<s>
Examples	O
include	O
Huffman	B-General_Concept
coding	I-General_Concept
(	O
common	O
constructions	O
should	O
be	O
short	O
)	O
,	O
good	O
end-weighting	O
(	O
the	O
important	O
information	O
should	O
come	O
first	O
)	O
,	O
and	O
a	O
large	O
collection	O
of	O
language	O
primitives	O
.	O
</s>
<s>
Perl	B-Language
favors	O
language	B-Language
constructs	I-Language
that	O
are	O
concise	O
and	O
natural	O
for	O
humans	O
to	O
write	O
,	O
even	O
where	O
they	O
complicate	O
the	O
Perl	B-Language
interpreter	I-Language
.	O
</s>
<s>
Perl	B-Language
's	O
syntax	O
reflects	O
the	O
idea	O
that	O
"	O
things	O
that	O
are	O
different	O
should	O
look	O
different.	O
"	O
</s>
<s>
For	O
example	O
,	O
scalars	O
,	O
arrays	O
,	O
and	O
hashes	B-Application
have	O
different	O
leading	O
sigils	O
.	O
</s>
<s>
Strings	O
and	O
regular	B-Language
expressions	I-Language
have	O
different	O
standard	O
delimiters	O
.	O
</s>
<s>
This	O
approach	O
can	O
be	O
contrasted	O
with	O
a	O
language	O
such	O
as	O
Lisp	B-Language
,	O
where	O
the	O
same	O
basic	O
syntax	O
,	O
composed	O
of	O
simple	O
and	O
universal	O
symbolic	B-Protocol
expressions	I-Protocol
,	O
is	O
used	O
for	O
all	O
purposes	O
.	O
</s>
<s>
Perl	B-Language
does	O
not	O
enforce	O
any	O
particular	O
programming	O
paradigm	O
(	O
procedural	B-Application
,	O
object-oriented	B-Language
,	O
functional	B-Language
,	O
or	O
others	O
)	O
or	O
even	O
require	O
the	O
programmer	O
to	O
choose	O
among	O
them	O
.	O
</s>
<s>
There	O
is	O
a	O
broad	O
practical	O
bent	O
to	O
both	O
the	O
Perl	B-Language
language	I-Language
and	O
the	O
community	O
and	O
culture	O
that	O
surround	O
it	O
.	O
</s>
<s>
The	O
preface	O
to	O
Programming	O
Perl	B-Language
begins	O
:	O
"	O
Perl	B-Language
is	O
a	O
language	O
for	O
getting	O
your	O
job	O
done.	O
"	O
</s>
<s>
One	O
consequence	O
of	O
this	O
is	O
that	O
Perl	B-Language
is	O
not	O
a	O
tidy	O
language	O
.	O
</s>
<s>
It	O
includes	O
many	O
features	O
,	O
tolerates	O
exceptions	O
to	O
its	O
rules	O
,	O
and	O
employs	O
heuristics	B-Algorithm
to	O
resolve	O
syntactical	O
ambiguities	O
.	O
</s>
<s>
Because	O
of	O
the	O
forgiving	O
nature	O
of	O
the	O
compiler	B-Language
,	O
bugs	B-Error_Name
can	O
sometimes	O
be	O
hard	O
to	O
find	O
.	O
</s>
<s>
Perl	B-Language
's	O
function	O
documentation	O
remarks	O
on	O
the	O
variant	O
behavior	O
of	O
built-in	O
functions	O
in	O
list	O
and	O
scalar	O
contexts	O
by	O
saying	O
,	O
"	O
In	O
general	O
,	O
they	O
do	O
what	O
you	O
want	O
,	O
unless	O
you	O
want	O
consistency.	O
"	O
</s>
<s>
No	O
written	O
specification	B-Application
or	O
standard	O
for	O
the	O
Perl	B-Language
language	I-Language
exists	O
for	O
Perl	B-Language
versions	O
through	O
Perl	B-Language
5	O
,	O
and	O
there	O
are	O
no	O
plans	O
to	O
create	O
one	O
for	O
the	O
current	O
version	O
of	O
Perl	B-Language
.	O
</s>
<s>
There	O
has	O
been	O
only	O
one	O
implementation	O
of	O
the	O
interpreter	B-Application
,	O
and	O
the	O
language	O
has	O
evolved	O
along	O
with	O
it	O
.	O
</s>
<s>
That	O
interpreter	B-Application
,	O
together	O
with	O
its	O
functional	B-Application
tests	I-Application
,	O
stands	O
as	O
a	O
de	O
facto	O
specification	B-Application
of	O
the	O
language	O
.	O
</s>
<s>
Perl	B-Application
6	I-Application
,	O
however	O
,	O
started	O
with	O
a	O
specification	B-Application
,	O
and	O
several	O
projects	O
aim	O
to	O
implement	O
some	O
or	O
all	O
of	O
the	O
specification	B-Application
.	O
</s>
<s>
Perl	B-Language
has	O
many	O
and	O
varied	O
applications	O
,	O
compounded	O
by	O
the	O
availability	O
of	O
many	O
standard	O
and	O
third-party	O
modules	B-Language
.	O
</s>
<s>
Perl	B-Language
has	O
chiefly	O
been	O
used	O
to	O
write	O
CGI	B-Language
scripts	I-Language
:	O
large	O
projects	O
written	O
in	O
Perl	B-Language
include	O
cPanel	B-Protocol
,	O
Slash	B-Protocol
,	O
Bugzilla	B-Application
,	O
RT	B-Language
,	O
TWiki	B-Language
,	O
and	O
Movable	B-Protocol
Type	I-Protocol
;	O
high-traffic	O
websites	O
that	O
use	O
Perl	B-Language
extensively	O
include	O
Priceline.com,	O
Craigslist	O
,	O
IMDb	O
,	O
LiveJournal	B-Application
,	O
DuckDuckGo	B-Application
,	O
Slashdot	O
and	O
Ticketmaster	O
.	O
</s>
<s>
It	O
is	O
also	O
an	O
optional	O
component	O
of	O
the	O
popular	O
LAMP	B-Application
technology	O
stack	O
for	O
Web	O
development	O
,	O
in	O
lieu	O
of	O
PHP	B-Application
or	O
Python	B-Language
.	O
</s>
<s>
Perl	B-Language
is	O
used	O
extensively	O
as	O
a	O
system	B-Language
programming	I-Language
language	I-Language
in	O
the	O
Debian	O
Linux	B-Application
distribution	O
.	O
</s>
<s>
Perl	B-Language
is	O
often	O
used	O
as	O
a	O
glue	O
language	O
,	O
tying	O
together	O
systems	O
and	O
interfaces	O
that	O
were	O
not	O
specifically	O
designed	O
to	O
interoperate	O
,	O
and	O
for	O
"	O
data	B-General_Concept
munging	I-General_Concept
,	O
"	O
that	O
is	O
,	O
converting	O
or	O
processing	O
large	O
amounts	O
of	O
data	O
for	O
tasks	O
such	O
as	O
creating	O
reports	O
.	O
</s>
<s>
The	O
combination	O
makes	O
Perl	B-Language
a	O
popular	O
all-purpose	O
language	O
for	O
system	B-Application
administrators	I-Application
,	O
particularly	O
because	O
short	O
programs	O
,	O
often	O
called	O
"	O
one-liner	B-Language
programs	I-Language
,	O
"	O
can	O
be	O
entered	O
and	O
run	O
on	O
a	O
single	O
command	B-Application
line	I-Application
.	O
</s>
<s>
Perl	B-Language
code	O
can	O
be	O
made	O
portable	O
across	O
Windows	B-Application
and	O
Unix	B-Application
;	O
such	O
code	O
is	O
often	O
used	O
by	O
suppliers	O
of	O
software	O
(	O
both	O
COTS	O
and	O
bespoke	O
)	O
to	O
simplify	O
packaging	O
and	O
maintenance	O
of	O
software	O
build	O
-	O
and	O
deployment-scripts	O
.	O
</s>
<s>
Perl/Tk	B-Application
and	O
wxPerl	B-Language
are	O
commonly	O
used	O
to	O
add	O
graphical	B-Application
user	I-Application
interfaces	I-Application
to	O
Perl	B-Language
scripts	O
.	O
</s>
<s>
Perl	B-Language
is	O
implemented	O
as	O
a	O
core	O
interpreter	B-Application
,	O
written	O
in	O
C	B-Language
,	O
together	O
with	O
a	O
large	O
collection	O
of	O
modules	B-Language
,	O
written	O
in	O
Perl	B-Language
and	O
C	B-Language
.	O
,	O
the	O
interpreter	B-Application
is	O
150,000	O
lines	O
of	O
C	B-Language
code	O
and	O
compiles	B-Language
to	O
a	O
1MB	O
executable	O
on	O
typical	O
machine	O
architectures	O
.	O
</s>
<s>
Alternatively	O
,	O
the	O
interpreter	B-Application
can	O
be	O
compiled	B-Language
to	O
a	O
link	O
library	O
and	O
embedded	O
in	O
other	O
programs	O
.	O
</s>
<s>
There	O
are	O
nearly	O
500	O
modules	B-Language
in	O
the	O
distribution	O
,	O
comprising	O
200,000	O
lines	O
of	O
Perl	B-Language
and	O
an	O
additional	O
350,000	O
lines	O
of	O
C	B-Language
code	O
(	O
much	O
of	O
the	O
C	B-Language
code	O
in	O
the	O
modules	B-Language
consists	O
of	O
character	B-General_Concept
encoding	I-General_Concept
tables	O
)	O
.	O
</s>
<s>
The	O
interpreter	B-Application
has	O
an	O
object-oriented	B-Language
architecture	O
.	O
</s>
<s>
All	O
of	O
the	O
elements	O
of	O
the	O
Perl	B-Language
language	I-Language
—	O
scalars	O
,	O
arrays	O
,	O
hashes	B-Application
,	O
coderefs	O
,	O
file	B-Application
handles	I-Application
—	O
are	O
represented	O
in	O
the	O
interpreter	B-Application
by	O
C	B-Language
structs	I-Language
.	O
</s>
<s>
Operations	O
on	O
these	O
structs	B-Language
are	O
defined	O
by	O
a	O
large	O
collection	O
of	O
macros	O
,	O
typedefs	B-Language
,	O
and	O
functions	O
;	O
these	O
constitute	O
the	O
Perl	B-Language
C	B-Language
API	B-Application
.	O
</s>
<s>
The	O
Perl	B-Language
API	B-Application
can	O
be	O
bewildering	O
to	O
the	O
uninitiated	O
,	O
but	O
its	O
entry	O
points	O
follow	O
a	O
consistent	O
naming	B-Protocol
scheme	I-Protocol
,	O
which	O
provides	O
guidance	O
to	O
those	O
who	O
use	O
it	O
.	O
</s>
<s>
The	O
life	O
of	O
a	O
Perl	B-Language
interpreter	I-Language
divides	O
broadly	O
into	O
a	O
compile	B-Language
phase	O
and	O
a	O
run	O
phase	O
.	O
</s>
<s>
In	O
Perl	B-Language
,	O
the	O
phases	O
are	O
the	O
major	O
stages	O
in	O
the	O
interpreter	B-Application
's	O
life-cycle	O
.	O
</s>
<s>
Each	O
interpreter	B-Application
goes	O
through	O
each	O
phase	O
only	O
once	O
,	O
and	O
the	O
phases	O
follow	O
in	O
a	O
fixed	O
sequence	O
.	O
</s>
<s>
Most	O
of	O
what	O
happens	O
in	O
Perl	B-Language
's	O
compile	B-Language
phase	O
is	O
compilation	B-Language
,	O
and	O
most	O
of	O
what	O
happens	O
in	O
Perl	B-Language
's	O
run	O
phase	O
is	O
execution	O
,	O
but	O
there	O
are	O
significant	O
exceptions	O
.	O
</s>
<s>
Perl	B-Language
makes	O
important	O
use	O
of	O
its	O
capability	O
to	O
execute	O
Perl	B-Language
code	O
during	O
the	O
compile	B-Language
phase	O
.	O
</s>
<s>
Perl	B-Language
will	O
also	O
delay	O
compilation	B-Language
into	O
the	O
run	O
phase	O
.	O
</s>
<s>
The	O
terms	O
that	O
indicate	O
the	O
kind	O
of	O
processing	O
that	O
is	O
actually	O
occurring	O
at	O
any	O
moment	O
are	O
compile	B-Application
time	I-Application
and	O
run	B-Library
time	I-Library
.	O
</s>
<s>
Perl	B-Language
is	O
in	O
compile	B-Application
time	I-Application
at	O
most	O
points	O
during	O
the	O
compile	B-Language
phase	O
,	O
but	O
compile	B-Application
time	I-Application
may	O
also	O
be	O
entered	O
during	O
the	O
run	O
phase	O
.	O
</s>
<s>
The	O
compile	B-Application
time	I-Application
for	O
code	O
in	O
a	O
string	O
argument	O
passed	O
to	O
the	O
eval	O
built-in	O
occurs	O
during	O
the	O
run	O
phase	O
.	O
</s>
<s>
Perl	B-Language
is	O
often	O
in	O
run	B-Library
time	I-Library
during	O
the	O
compile	B-Language
phase	O
and	O
spends	O
most	O
of	O
the	O
run	O
phase	O
in	O
run	B-Library
time	I-Library
.	O
</s>
<s>
Code	O
in	O
BEGIN	O
blocks	O
executes	O
at	O
run	B-Library
time	I-Library
but	O
in	O
the	O
compile	B-Language
phase	O
.	O
</s>
<s>
At	O
compile	B-Application
time	I-Application
,	O
the	O
interpreter	B-Application
parses	B-Language
Perl	B-Language
code	O
into	O
a	O
syntax	B-Data_Structure
tree	I-Data_Structure
.	O
</s>
<s>
At	O
run	B-Library
time	I-Library
,	O
it	O
executes	O
the	O
program	O
by	O
walking	B-Algorithm
the	I-Algorithm
tree	I-Algorithm
.	O
</s>
<s>
Text	O
is	O
parsed	B-Language
only	O
once	O
,	O
and	O
the	O
syntax	B-Data_Structure
tree	I-Data_Structure
is	O
subject	O
to	O
optimization	O
before	O
it	O
is	O
executed	O
,	O
so	O
that	O
execution	O
is	O
relatively	O
efficient	O
.	O
</s>
<s>
Compile-time	B-Application
optimizations	O
on	O
the	O
syntax	B-Data_Structure
tree	I-Data_Structure
include	O
constant	O
folding	O
and	O
context	O
propagation	O
,	O
but	O
peephole	O
optimization	O
is	O
also	O
performed	O
.	O
</s>
<s>
Perl	B-Language
has	O
a	O
Turing-complete	O
grammar	O
because	O
parsing	B-Language
can	O
be	O
affected	O
by	O
run-time	O
code	O
executed	O
during	O
the	O
compile	B-Language
phase	O
.	O
</s>
<s>
Therefore	O
,	O
Perl	B-Language
cannot	O
be	O
parsed	B-Language
by	O
a	O
straight	O
Lex/Yacc	O
lexer/parser	O
combination	O
.	O
</s>
<s>
Instead	O
,	O
the	O
interpreter	B-Application
implements	O
its	O
own	O
lexer	B-Application
,	O
which	O
coordinates	O
with	O
a	O
modified	O
GNU	B-Application
bison	I-Application
parser	B-Language
to	O
resolve	O
ambiguities	O
in	O
the	O
language	O
.	O
</s>
<s>
It	O
is	O
often	O
said	O
that	O
"	O
Only	O
perl	B-Language
can	O
parse	B-Language
Perl	B-Language
,	O
"	O
meaning	O
that	O
only	O
the	O
Perl	B-Language
interpreter	I-Language
(	O
perl	B-Language
)	O
can	O
parse	B-Language
the	O
Perl	B-Language
language	I-Language
(	O
Perl	B-Language
)	O
,	O
but	O
even	O
this	O
is	O
not	O
,	O
in	O
general	O
,	O
true	O
.	O
</s>
<s>
Because	O
the	O
Perl	B-Language
interpreter	I-Language
can	O
simulate	O
a	O
Turing	O
machine	O
during	O
its	O
compile	B-Language
phase	O
,	O
it	O
would	O
need	O
to	O
decide	O
the	O
halting	O
problem	O
in	O
order	O
to	O
complete	O
parsing	B-Language
in	O
every	O
case	O
.	O
</s>
<s>
It	O
is	O
a	O
longstanding	O
result	O
that	O
the	O
halting	O
problem	O
is	O
undecidable	O
,	O
and	O
therefore	O
not	O
even	O
Perl	B-Language
can	O
always	O
parse	B-Language
Perl	B-Language
.	O
</s>
<s>
Perl	B-Language
makes	O
the	O
unusual	O
choice	O
of	O
giving	O
the	O
user	O
access	O
to	O
its	O
full	O
programming	O
power	O
in	O
its	O
own	O
compile	B-Language
phase	O
.	O
</s>
<s>
Other	O
programs	O
that	O
undertake	O
to	O
parse	B-Language
Perl	B-Language
,	O
such	O
as	O
source-code	O
analyzers	O
and	O
auto-indenters	O
,	O
have	O
to	O
contend	O
not	O
only	O
with	O
ambiguous	O
syntactic	B-Language
constructs	I-Language
but	O
also	O
with	O
the	O
undecidability	O
of	O
Perl	B-Language
parsing	B-Language
in	O
the	O
general	O
case	O
.	O
</s>
<s>
Adam	O
Kennedy	O
's	O
PPI	O
project	O
focused	O
on	O
parsing	B-Language
Perl	B-Language
code	O
as	O
a	O
document	O
(	O
retaining	O
its	O
integrity	O
as	O
a	O
document	O
)	O
,	O
instead	O
of	O
parsing	B-Language
Perl	B-Language
as	O
executable	O
code	O
(	O
that	O
not	O
even	O
Perl	B-Language
itself	O
can	O
always	O
do	O
)	O
.	O
</s>
<s>
It	O
was	O
Kennedy	O
who	O
first	O
conjectured	O
that	O
"	O
parsing	B-Language
Perl	B-Language
suffers	O
from	O
the	O
'	O
halting	O
problem	O
 '	O
,	O
"	O
which	O
was	O
later	O
proved	O
.	O
</s>
<s>
Perl	B-Language
is	O
distributed	O
with	O
over	O
250,000	O
functional	B-Application
tests	I-Application
for	O
core	O
Perl	B-Language
language	I-Language
and	O
over	O
250,000	O
functional	B-Application
tests	I-Application
for	O
core	O
modules	B-Language
.	O
</s>
<s>
These	O
run	O
as	O
part	O
of	O
the	O
normal	O
build	O
process	O
and	O
extensively	O
exercise	O
the	O
interpreter	B-Application
and	O
its	O
core	O
modules	B-Language
.	O
</s>
<s>
Perl	B-Language
developers	O
rely	O
on	O
the	O
functional	B-Application
tests	I-Application
to	O
ensure	O
that	O
changes	O
to	O
the	O
interpreter	B-Application
do	O
not	O
introduce	O
software	B-Error_Name
bugs	I-Error_Name
;	O
additionally	O
,	O
Perl	B-Language
users	O
who	O
see	O
that	O
the	O
interpreter	B-Application
passes	O
its	O
functional	B-Application
tests	I-Application
on	O
their	O
system	O
can	O
have	O
a	O
high	O
degree	O
of	O
confidence	O
that	O
it	O
is	O
working	O
properly	O
.	O
</s>
<s>
Perl	B-Language
is	O
dual	B-License
licensed	I-License
under	O
both	O
the	O
Artistic	B-License
License	I-License
1.0	O
and	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
Distributions	O
are	O
available	O
for	O
most	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
It	O
is	O
particularly	O
prevalent	O
on	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
but	O
it	O
has	O
been	O
ported	O
to	O
most	O
modern	O
(	O
and	O
many	O
obsolete	O
)	O
platforms	O
.	O
</s>
<s>
With	O
only	O
six	O
reported	O
exceptions	O
,	O
Perl	B-Language
can	O
be	O
compiled	B-Language
from	O
source	O
code	O
on	O
all	O
POSIX-compliant	O
,	O
or	O
otherwise-Unix-compatible	O
,	O
platforms	O
.	O
</s>
<s>
Because	O
of	O
unusual	O
changes	O
required	O
for	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
environment	O
,	O
a	O
special	O
port	O
called	O
MacPerl	O
was	O
shipped	O
independently	O
.	O
</s>
<s>
The	O
Comprehensive	B-Language
Perl	I-Language
Archive	I-Language
Network	I-Language
carries	O
a	O
complete	O
list	O
of	O
supported	O
platforms	O
with	O
links	O
to	O
the	O
distributions	O
available	O
on	O
each	O
.	O
</s>
<s>
CPAN	B-Language
is	O
also	O
the	O
source	O
for	O
publicly	O
available	O
Perl	B-Language
modules	I-Language
that	O
are	O
not	O
part	O
of	O
the	O
core	O
Perl	B-Language
distribution	O
.	O
</s>
<s>
Users	O
of	O
Microsoft	B-Application
Windows	I-Application
typically	O
install	O
one	O
of	O
the	O
native	O
binary	O
distributions	O
of	O
Perl	B-Language
for	O
Win32	O
,	O
most	O
commonly	O
Strawberry	B-Language
Perl	I-Language
or	O
ActivePerl	B-Language
.	O
</s>
<s>
Compiling	B-Language
Perl	B-Language
from	O
source	O
code	O
under	O
Windows	B-Application
is	O
possible	O
,	O
but	O
most	O
installations	O
lack	O
the	O
requisite	O
C	B-Language
compiler	B-Language
and	O
build	O
tools	O
.	O
</s>
<s>
This	O
also	O
makes	O
it	O
difficult	O
to	O
install	O
modules	B-Language
from	O
the	O
CPAN	B-Language
,	O
particularly	O
those	O
that	O
are	O
partially	O
written	O
in	O
C	B-Language
.	O
</s>
<s>
ActivePerl	B-Language
is	O
a	O
closed-source	O
distribution	O
from	O
ActiveState	O
that	O
has	O
regular	O
releases	O
that	O
track	O
the	O
core	O
Perl	B-Language
releases	O
.	O
</s>
<s>
The	O
distribution	O
previously	O
included	O
the	O
Perl	B-Language
package	I-Language
manager	I-Language
(	O
PPM	O
)	O
,	O
a	O
popular	O
tool	O
for	O
installing	O
,	O
removing	O
,	O
upgrading	O
,	O
and	O
managing	O
the	O
use	O
of	O
common	O
Perl	B-Language
modules	I-Language
;	O
however	O
,	O
this	O
tool	O
was	O
discontinued	O
as	O
of	O
ActivePerl	B-Language
5.28	O
.	O
</s>
<s>
Included	O
also	O
is	O
PerlScript	O
,	O
a	O
Windows	B-Application
Script	O
Host	O
(	O
WSH	O
)	O
engine	O
implementing	O
the	O
Perl	B-Language
language	I-Language
.	O
</s>
<s>
Visual	B-Language
Perl	I-Language
is	O
an	O
ActiveState	O
tool	O
that	O
adds	O
Perl	B-Language
to	O
the	O
Visual	O
Studio	O
.NET	O
development	O
suite	O
.	O
</s>
<s>
A	O
VBScript-to-Perl	O
converter	O
,	O
as	O
well	O
as	O
a	O
Perl	B-Language
compiler	B-Language
for	O
Windows	B-Application
,	O
and	O
converters	O
of	O
awk	B-Application
and	O
sed	B-Application
to	O
Perl	B-Language
have	O
also	O
been	O
produced	O
by	O
this	O
company	O
and	O
included	O
on	O
the	O
ActiveState	O
CD	O
for	O
Windows	B-Application
,	O
which	O
includes	O
all	O
of	O
their	O
distributions	O
plus	O
the	O
Komodo	B-Language
IDE	I-Language
and	O
all	O
but	O
the	O
first	O
on	O
the	O
Unix/Linux/Posix	O
variant	O
thereof	O
in	O
2002	O
and	O
subsequently	O
.	O
</s>
<s>
Strawberry	B-Language
Perl	I-Language
is	O
an	O
open-source	O
distribution	O
for	O
Windows	B-Application
.	O
</s>
<s>
It	O
has	O
had	O
regular	O
,	O
quarterly	O
releases	O
since	O
January	O
2008	O
,	O
including	O
new	O
modules	B-Language
as	O
feedback	O
and	O
requests	O
come	O
in	O
.	O
</s>
<s>
Strawberry	B-Language
Perl	I-Language
aims	O
to	O
be	O
able	O
to	O
install	O
modules	B-Language
like	O
standard	O
Perl	B-Language
distributions	O
on	O
other	O
platforms	O
,	O
including	O
compiling	B-Language
XS	B-Language
modules	B-Language
.	O
</s>
<s>
The	O
Cygwin	B-Language
emulation	O
layer	O
is	O
another	O
way	O
of	O
running	O
Perl	B-Language
under	O
Windows	B-Application
.	O
</s>
<s>
Cygwin	B-Language
provides	O
a	O
Unix-like	B-Operating_System
environment	O
on	O
Windows	B-Application
,	O
and	O
both	O
Perl	B-Language
and	O
CPAN	B-Language
are	O
available	O
as	O
standard	O
pre-compiled	O
packages	O
in	O
the	O
Cygwin	B-Language
setup	O
program	O
.	O
</s>
<s>
Since	O
Cygwin	B-Language
also	O
includes	O
gcc	B-Application
,	O
compiling	B-Language
Perl	B-Language
from	O
source	O
is	O
also	O
possible	O
.	O
</s>
<s>
A	O
Perl	B-Language
executable	O
is	O
included	O
in	O
several	O
Windows	B-Application
Resource	O
kits	O
in	O
the	O
directory	O
with	O
other	O
scripting	O
tools	O
.	O
</s>
<s>
Implementations	O
of	O
Perl	B-Language
come	O
with	O
the	O
MKS	B-Application
Toolkit	I-Application
,	O
Interix	B-Operating_System
(	O
the	O
base	O
of	O
earlier	O
implementations	O
of	O
Windows	B-Application
Services	O
for	O
Unix	B-Application
)	O
,	O
and	O
UWIN	B-Application
.	O
</s>
<s>
Perl	B-Language
's	O
text-handling	O
capabilities	O
can	O
be	O
used	O
for	O
generating	O
SQL	B-Language
queries	O
;	O
arrays	O
,	O
hashes	B-Application
,	O
and	O
automatic	O
memory	B-General_Concept
management	I-General_Concept
make	O
it	O
easy	O
to	O
collect	O
and	O
process	O
the	O
returned	O
data	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
Tim	O
Bunce	O
's	O
Perl	B-Language
DBI	I-Language
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
,	O
the	O
arguments	O
to	O
the	O
API	B-Application
can	O
be	O
the	O
text	O
of	O
SQL	B-Language
queries	O
;	O
thus	O
it	O
is	O
possible	O
to	O
program	O
in	O
multiple	O
languages	O
at	O
the	O
same	O
time	O
(	O
e.g.	O
,	O
for	O
generating	O
a	O
Web	O
page	O
using	O
HTML	B-Language
,	O
JavaScript	B-Language
,	O
and	O
SQL	B-Language
in	O
a	O
here	O
document	O
)	O
.	O
</s>
<s>
The	O
use	O
of	O
Perl	B-Language
variable	O
interpolation	O
to	O
programmatically	O
customize	O
each	O
of	O
the	O
SQL	B-Language
queries	O
,	O
and	O
the	O
specification	B-Application
of	O
Perl	B-Language
arrays	O
or	O
hashes	B-Application
as	O
the	O
structures	O
to	O
programmatically	O
hold	O
the	O
resulting	O
data	B-General_Concept
sets	I-General_Concept
from	O
each	O
SQL	B-Language
query	O
,	O
allows	O
a	O
high-level	B-Language
mechanism	O
for	O
handling	O
large	O
amounts	O
of	O
data	O
for	O
post-processing	O
by	O
a	O
Perl	B-Language
subprogram	O
.	O
</s>
<s>
In	O
early	O
versions	O
of	O
Perl	B-Language
,	O
database	O
interfaces	O
were	O
created	O
by	O
relinking	O
the	O
interpreter	B-Application
with	O
a	O
client-side	B-Operating_System
database	O
library	O
.	O
</s>
<s>
This	O
was	O
sufficiently	O
difficult	O
that	O
it	O
was	O
done	O
for	O
only	O
a	O
few	O
of	O
the	O
most-important	O
and	O
most	O
widely	O
used	O
databases	O
,	O
and	O
it	O
restricted	O
the	O
resulting	O
perl	B-Language
executable	O
to	O
using	O
just	O
one	O
database	O
interface	O
at	O
a	O
time	O
.	O
</s>
<s>
In	O
Perl	B-Language
5	O
,	O
database	O
interfaces	O
are	O
implemented	O
by	O
Perl	B-Language
DBI	I-Language
modules	B-Language
.	O
</s>
<s>
The	O
DBI	O
(	O
Database	O
Interface	O
)	O
module	B-Language
presents	O
a	O
single	O
,	O
database-independent	O
interface	O
to	O
Perl	B-Language
applications	O
,	O
while	O
the	O
DBD	O
(	O
Database	O
Driver	O
)	O
modules	B-Language
handle	O
the	O
details	O
of	O
accessing	O
some	O
50	O
different	O
databases	O
;	O
there	O
are	O
DBD	O
drivers	O
for	O
most	O
ANSI	O
SQL	B-Language
databases	I-Language
.	O
</s>
<s>
DBI	O
provides	O
caching	O
for	O
database	O
handles	O
and	O
queries	O
,	O
which	O
can	O
greatly	O
improve	O
performance	O
in	O
long-lived	O
execution	O
environments	O
such	O
as	O
mod_perl	O
,	O
helping	O
high-volume	O
systems	O
avert	O
load	O
spikes	O
as	O
in	O
the	O
Slashdot	B-General_Concept
effect	I-General_Concept
.	O
</s>
<s>
In	O
modern	O
Perl	B-Language
applications	O
,	O
especially	O
those	O
written	O
using	O
web	B-Application
frameworks	I-Application
such	O
as	O
Catalyst	B-Language
,	O
the	O
DBI	O
module	B-Language
is	O
often	O
used	O
indirectly	O
via	O
object-relational	B-General_Concept
mappers	I-General_Concept
such	O
as	O
DBIx::Class	B-Language
,	O
Class::DBI	O
or	O
Rose::DB::Object	O
that	O
generate	O
SQL	B-Language
queries	O
and	O
handle	O
data	O
transparently	O
to	O
the	O
application	O
author	O
.	O
</s>
<s>
The	O
submitted	O
Perl	B-Language
implementations	O
typically	O
perform	O
toward	O
the	O
high	O
end	O
of	O
the	O
memory-usage	O
spectrum	O
and	O
give	O
varied	O
speed	O
results	O
.	O
</s>
<s>
Perl	B-Language
's	O
performance	O
in	O
the	O
benchmarks	O
game	O
is	O
typical	O
for	O
interpreted	B-Application
languages	I-Application
.	O
</s>
<s>
Large	O
Perl	B-Language
programs	O
start	O
more	O
slowly	O
than	O
similar	O
programs	O
in	O
compiled	B-Language
languages	O
because	O
Perl	B-Language
has	O
to	O
compile	B-Language
the	O
source	O
every	O
time	O
it	O
runs	O
.	O
</s>
<s>
In	O
a	O
talk	O
at	O
the	O
YAPC::Europe	B-Language
2005	I-Language
conference	O
and	O
subsequent	O
article	O
"	O
A	O
Timely	O
Start	O
,	O
"	O
Jean-Louis	O
Leroy	O
found	O
that	O
his	O
Perl	B-Language
programs	O
took	O
much	O
longer	O
to	O
run	O
than	O
expected	O
because	O
the	O
perl	B-Language
interpreter	I-Language
spent	O
significant	O
time	O
finding	O
modules	B-Language
within	O
his	O
over-large	O
include	O
path	O
.	O
</s>
<s>
Unlike	O
Java	O
,	O
Python	B-Language
,	O
and	O
Ruby	B-Language
,	O
Perl	B-Language
has	O
only	O
experimental	O
support	O
for	O
pre-compiling	O
.	O
</s>
<s>
Therefore	O
,	O
Perl	B-Language
programs	O
pay	O
this	O
overhead	O
penalty	O
on	O
every	O
execution	O
.	O
</s>
<s>
The	O
run	O
phase	O
of	O
typical	O
programs	O
is	O
long	O
enough	O
that	O
amortized	B-General_Concept
startup	O
time	O
is	O
not	O
substantial	O
,	O
but	O
benchmarks	O
that	O
measure	O
very	O
short	O
execution	B-Library
times	I-Library
are	O
likely	O
to	O
be	O
skewed	O
due	O
to	O
this	O
overhead	O
.	O
</s>
<s>
The	O
first	O
such	O
tool	O
was	O
Apache	O
's	O
mod_perl	O
,	O
which	O
sought	O
to	O
address	O
one	O
of	O
the	O
most-common	O
reasons	O
that	O
small	O
Perl	B-Language
programs	O
were	O
invoked	O
rapidly	O
:	O
CGI	B-Language
Web	O
development	O
.	O
</s>
<s>
ActivePerl	B-Language
,	O
via	O
Microsoft	O
ISAPI	B-Library
,	O
provides	O
similar	O
performance	O
improvements	O
.	O
</s>
<s>
Once	O
Perl	B-Language
code	O
is	O
compiled	B-Language
,	O
there	O
is	O
additional	O
overhead	O
during	O
the	O
execution	O
phase	O
that	O
typically	O
is	O
n't	O
present	O
for	O
programs	O
written	O
in	O
compiled	B-Language
languages	O
such	O
as	O
C	B-Language
or	O
C++	B-Language
.	O
</s>
<s>
Examples	O
of	O
such	O
overhead	O
include	O
bytecode	O
interpretation	O
,	O
reference-counting	O
memory	B-General_Concept
management	I-General_Concept
,	O
and	O
dynamic	O
type-checking	O
.	O
</s>
<s>
The	O
most	O
critical	O
routines	O
can	O
be	O
written	O
in	O
other	O
languages	O
(	O
such	O
as	O
C	B-Language
)	O
,	O
which	O
can	O
be	O
connected	O
to	O
Perl	B-Language
via	O
simple	O
Inline	O
modules	B-Language
or	O
the	O
more	O
complex	O
,	O
but	O
flexible	O
,	O
XS	B-Language
mechanism	O
.	O
</s>
<s>
Perl	B-Language
5	O
,	O
the	O
language	O
usually	O
referred	O
to	O
as	O
"	O
Perl	B-Language
"	O
,	O
continues	O
to	O
be	O
actively	O
developed	O
.	O
</s>
<s>
Perl	B-Language
5.12.0	O
was	O
released	O
in	O
April	O
2010	O
with	O
some	O
new	O
features	O
influenced	O
by	O
the	O
design	O
of	O
Perl	B-Application
6	I-Application
,	O
followed	O
by	O
Perl	B-Language
5.14.1	O
(	O
released	O
on	O
June	O
17	O
,	O
2011	O
)	O
,	O
Perl	B-Language
5.16.1	O
(	O
released	O
on	O
August	O
9	O
,	O
2012	O
.	O
</s>
<s>
)	O
,	O
and	O
Perl	B-Language
5.18.0	O
(	O
released	O
on	O
May	O
18	O
,	O
2013	O
)	O
.	O
</s>
<s>
Perl	B-Language
5	O
development	O
versions	O
are	O
released	O
on	O
a	O
monthly	O
basis	O
,	O
with	O
major	O
releases	O
coming	O
out	O
once	O
per	O
year	O
.	O
</s>
<s>
The	O
relative	O
proportion	O
of	O
Internet	O
searches	O
for	O
"	O
Perl	B-Language
programming	I-Language
"	O
,	O
as	O
compared	O
with	O
similar	O
searches	O
for	O
other	O
programming	O
languages	O
,	O
steadily	O
declined	O
from	O
about	O
10%	O
in	O
2005	O
to	O
about	O
2%	O
in	O
2011	O
,	O
and	O
to	O
about	O
0.7	O
%	O
in	O
2020	O
.	O
</s>
<s>
At	O
the	O
2000	O
Perl	B-Language
Conference	O
,	O
Jon	O
Orwant	O
made	O
a	O
case	O
for	O
a	O
major	O
new	O
language-initiative	O
.	O
</s>
<s>
This	O
led	O
to	O
a	O
decision	O
to	O
begin	O
work	O
on	O
a	O
redesign	O
of	O
the	O
language	O
,	O
to	O
be	O
called	O
Perl	B-Application
6	I-Application
.	O
</s>
<s>
Proposals	O
for	O
new	O
language	O
features	O
were	O
solicited	O
from	O
the	O
Perl	B-Language
community	O
at	O
large	O
,	O
which	O
submitted	O
more	O
than	O
300	O
RFCs	O
.	O
</s>
<s>
Wall	O
spent	O
the	O
next	O
few	O
years	O
digesting	O
the	O
RFCs	O
and	O
synthesizing	O
them	O
into	O
a	O
coherent	O
framework	O
for	O
Perl	B-Application
6	I-Application
.	O
</s>
<s>
He	O
presented	O
his	O
design	O
for	O
Perl	B-Application
6	I-Application
in	O
a	O
series	O
of	O
documents	O
called	O
"	O
apocalypses	O
"	O
numbered	O
to	O
correspond	O
to	O
chapters	O
in	O
Programming	O
Perl	B-Language
.	O
</s>
<s>
,	O
the	O
developing	O
specification	B-Application
of	O
Perl	B-Application
6	I-Application
was	O
encapsulated	O
in	O
design	O
documents	O
called	O
Synopsesnumbered	O
to	O
correspond	O
to	O
Apocalypses	O
.	O
</s>
<s>
Thesis	O
work	O
by	O
Bradley	O
M	O
.	O
Kuhn	O
,	O
overseen	O
by	O
Wall	O
,	O
considered	O
the	O
possible	O
use	O
of	O
the	O
Java	B-Language
virtual	I-Language
machine	I-Language
as	O
a	O
runtime	B-Library
for	O
Perl	B-Language
.	O
</s>
<s>
In	O
2001	O
,	O
it	O
was	O
decided	O
that	O
Perl	B-Application
6	I-Application
would	O
run	O
on	O
a	O
cross-language	O
virtual	B-Architecture
machine	I-Architecture
called	O
Parrot	B-Language
.	O
</s>
<s>
This	O
will	O
mean	O
that	O
other	O
languages	O
targeting	O
the	O
Parrot	B-Language
will	O
gain	O
native	O
access	O
to	O
CPAN	B-Language
,	O
allowing	O
some	O
level	O
of	O
cross-language	O
development	O
.	O
</s>
<s>
In	O
2005	O
,	O
Audrey	O
Tang	O
created	O
the	O
Pugs	B-Language
project	O
,	O
an	O
implementation	O
of	O
Perl	B-Application
6	I-Application
in	O
Haskell	B-Language
.	O
</s>
<s>
This	O
acted	O
as	O
,	O
and	O
continues	O
to	O
act	O
as	O
,	O
a	O
test	O
platform	O
for	O
the	O
Perl	B-Application
6	I-Application
language	O
(	O
separate	O
from	O
the	O
development	O
of	O
the	O
actual	O
implementation	O
)	O
allowing	O
the	O
language	O
designers	O
to	O
explore	O
.	O
</s>
<s>
The	O
Pugs	B-Language
project	O
spawned	O
an	O
active	O
Perl/Haskell	O
cross-language	O
community	O
centered	O
around	O
the	O
Libera	O
Chat	O
#raku	O
IRC	B-Protocol
channel	O
.	O
</s>
<s>
Many	O
functional	B-Language
programming	I-Language
influences	O
were	O
absorbed	O
by	O
the	O
Perl	B-Application
6	I-Application
design	O
team	O
.	O
</s>
<s>
In	O
2012	O
,	O
Perl	B-Application
6	I-Application
development	O
was	O
centered	O
primarily	O
on	O
two	O
compilers	B-Language
:	O
</s>
<s>
Rakudo	B-Language
,	O
an	O
implementation	O
running	O
on	O
the	O
Parrot	B-Language
virtual	I-Language
machine	I-Language
and	O
the	O
Java	B-Language
virtual	I-Language
machine	I-Language
.	O
</s>
<s>
Niecza	O
,	O
which	O
targets	O
the	O
Common	O
Language	O
Runtime	B-Library
.	O
</s>
<s>
In	O
2013	O
,	O
MoarVM	B-Language
(	O
“	O
Metamodel	O
On	O
A	O
Runtime	B-Library
”	O
)	O
,	O
a	O
C	O
language-based	O
virtual	B-Architecture
machine	I-Architecture
designed	O
primarily	O
for	O
Rakudo	B-Language
was	O
announced	O
.	O
</s>
<s>
In	O
October	O
2019	O
,	O
Perl	B-Application
6	I-Application
was	O
renamed	O
to	O
Raku	B-Application
.	O
</s>
<s>
only	O
the	O
Rakudo	B-Language
implementation	O
and	O
MoarVM	B-Language
are	O
under	O
active	O
development	O
,	O
and	O
other	O
virtual	B-Architecture
machines	I-Architecture
,	O
such	O
as	O
the	O
Java	B-Language
Virtual	I-Language
Machine	I-Language
and	O
JavaScript	B-Language
,	O
are	O
supported	O
.	O
</s>
<s>
Perl	B-Language
7	O
was	O
announced	O
on	O
24	O
June	O
2020	O
at	O
"	O
The	B-Language
Perl	I-Language
Conference	I-Language
in	O
the	O
Cloud	O
"	O
as	O
the	O
successor	O
to	O
Perl	B-Language
5	O
.	O
</s>
<s>
Based	O
on	O
Perl	B-Language
5.32	O
,	O
Perl	B-Language
7	O
was	O
planned	O
to	O
be	O
backward	O
compatible	O
with	O
modern	O
Perl	B-Language
5	O
code	O
;	O
Perl	B-Language
5	O
code	O
,	O
without	O
boilerplate	O
(	O
pragma	O
)	O
header	O
needs	O
adding	O
use	O
compat::perl5	O
;	O
to	O
stay	O
compatible	O
,	O
but	O
modern	O
code	O
can	O
drop	O
some	O
of	O
the	O
boilerplate	O
.	O
</s>
<s>
The	O
plan	O
to	O
go	O
to	O
Perl	B-Language
7	O
brought	O
up	O
more	O
discussion	O
,	O
however	O
,	O
and	O
the	O
Perl	B-Language
Steering	O
Committee	O
canceled	O
it	O
to	O
avoid	O
issues	O
with	O
backward	O
compatibility	O
for	O
scripts	O
that	O
were	O
not	O
written	O
to	O
the	O
pragmas	O
and	O
modules	B-Language
that	O
would	O
become	O
the	O
default	O
in	O
Perl	B-Language
7	O
.	O
</s>
<s>
Perl	B-Language
7	O
will	O
only	O
come	O
out	O
when	O
the	O
developers	O
add	O
enough	O
features	O
to	O
warrant	O
a	O
major	O
release	O
upgrade	O
.	O
</s>
<s>
Perl	B-Language
's	O
culture	O
and	O
community	O
has	O
developed	O
alongside	O
the	O
language	O
itself	O
.	O
</s>
<s>
Usenet	B-Application
was	O
the	O
first	O
public	O
venue	O
in	O
which	O
Perl	B-Language
was	O
introduced	O
,	O
but	O
over	O
the	O
course	O
of	O
its	O
evolution	O
,	O
Perl	B-Language
's	O
community	O
was	O
shaped	O
by	O
the	O
growth	O
of	O
broadening	O
Internet-based	O
services	O
including	O
the	O
introduction	O
of	O
the	O
World	O
Wide	O
Web	O
.	O
</s>
<s>
The	O
community	O
that	O
surrounds	O
Perl	B-Language
was	O
,	O
in	O
fact	O
,	O
the	O
topic	O
of	O
Wall	O
's	O
first	O
"	O
State	O
of	O
the	O
Onion	O
"	O
talk	O
.	O
</s>
<s>
State	O
of	O
the	O
Onion	O
is	O
the	O
name	O
for	O
Wall	O
's	O
yearly	O
keynote-style	O
summaries	O
on	O
the	O
progress	O
of	O
Perl	B-Language
and	O
its	O
community	O
.	O
</s>
<s>
They	O
are	O
characterized	O
by	O
his	O
hallmark	O
humor	O
,	O
employing	O
references	O
to	O
Perl	B-Language
's	O
culture	O
,	O
the	O
wider	O
hacker	O
culture	O
,	O
Wall	O
's	O
linguistic	O
background	O
,	O
sometimes	O
his	O
family	O
life	O
,	O
and	O
occasionally	O
even	O
his	O
Christian	O
background	O
.	O
</s>
<s>
Each	O
talk	O
is	O
first	O
given	O
at	O
various	O
Perl	B-Language
conferences	O
and	O
is	O
eventually	O
also	O
published	O
online	O
.	O
</s>
<s>
In	O
email	O
,	O
Usenet	B-Application
,	O
and	O
message	O
board	O
postings	O
,	O
"	O
Just	O
another	O
Perl	B-Language
hacker	O
"	O
(	O
JAPH	O
)	O
programs	O
are	O
a	O
common	O
trend	O
,	O
originated	O
by	O
Randal	O
L	O
.	O
Schwartz	O
,	O
one	O
of	O
the	O
earliest	O
professional	O
Perl	B-Language
trainers	O
.	O
</s>
<s>
In	O
the	O
parlance	O
of	O
Perl	B-Language
culture	O
,	O
Perl	B-Language
programmers	O
are	O
known	O
as	O
Perl	B-Language
hackers	O
,	O
and	O
from	O
this	O
derives	O
the	O
practice	O
of	O
writing	O
short	O
programs	O
to	O
print	O
out	O
the	O
phrase	O
"	O
Just	O
another	O
Perl	B-Language
hacker	O
"	O
.	O
</s>
<s>
In	O
the	O
spirit	O
of	O
the	O
original	O
concept	O
,	O
these	O
programs	O
are	O
moderately	O
obfuscated	O
and	O
short	O
enough	O
to	O
fit	O
into	O
the	O
signature	O
of	O
an	O
email	O
or	O
Usenet	B-Application
message	O
.	O
</s>
<s>
Perl	B-Language
"	O
golf	B-Application
"	O
is	O
the	O
pastime	O
of	O
reducing	O
the	O
number	O
of	O
characters	O
(	O
key	O
"	O
strokes	O
"	O
)	O
used	O
in	O
a	O
Perl	B-Language
program	O
to	O
the	O
bare	O
minimum	O
,	O
much	O
in	O
the	O
same	O
way	O
that	O
golf	B-Application
players	O
seek	O
to	O
take	O
as	O
few	O
shots	O
as	O
possible	O
in	O
a	O
round	O
.	O
</s>
<s>
The	O
phrase	O
's	O
first	O
use	O
emphasized	O
the	O
difference	O
between	O
pedestrian	O
code	O
meant	O
to	O
teach	O
a	O
newcomer	O
and	O
terse	O
hacks	O
likely	O
to	O
amuse	O
experienced	O
Perl	B-Language
programmers	O
,	O
an	O
example	O
of	O
the	O
latter	O
being	O
JAPHs	O
that	O
were	O
already	O
used	O
in	O
signatures	O
in	O
Usenet	B-Application
postings	O
and	O
elsewhere	O
.	O
</s>
<s>
Similar	O
stunts	O
had	O
been	O
an	O
unnamed	O
pastime	O
in	O
the	O
language	O
APL	B-Language
in	O
previous	O
decades	O
.	O
</s>
<s>
The	O
use	O
of	O
Perl	B-Language
to	O
write	O
a	O
program	O
that	O
performed	O
RSA	B-Architecture
encryption	I-Architecture
prompted	O
a	O
widespread	O
and	O
practical	O
interest	O
in	O
this	O
pastime	O
.	O
</s>
<s>
In	O
subsequent	O
years	O
,	O
the	O
term	O
"	O
code	O
golf	B-Application
"	O
has	O
been	O
applied	O
to	O
the	O
pastime	O
in	O
other	O
languages	O
.	O
</s>
<s>
A	O
Perl	B-Language
Golf	B-Application
Apocalypse	O
was	O
held	O
at	O
Perl	B-Language
Conference	O
4.0	O
in	O
Monterey	O
,	O
California	O
in	O
July	O
2000	O
.	O
</s>
<s>
As	O
with	O
C	B-Language
,	O
obfuscated	O
code	O
competitions	O
were	O
a	O
well	O
known	O
pastime	O
in	O
the	O
late	O
1990s	O
.	O
</s>
<s>
The	O
Obfuscated	O
Perl	B-Language
Contest	O
was	O
a	O
competition	O
held	O
by	O
The	O
Perl	B-Language
Journal	O
from	O
1996	O
to	O
2000	O
that	O
made	O
an	O
arch	O
virtue	O
of	O
Perl	B-Language
's	O
syntactic	O
flexibility	O
.	O
</s>
<s>
Awards	O
were	O
given	O
for	O
categories	O
such	O
as	O
"	O
most	O
powerful	O
"	O
—	O
programs	O
that	O
made	O
efficient	O
use	O
of	O
space	O
—	O
and	O
"	O
best	O
four-line	O
signature	O
"	O
for	O
programs	O
that	O
fit	O
into	O
four	O
lines	O
of	O
76	O
characters	O
in	O
the	O
style	O
of	O
a	O
Usenet	B-Application
signature	O
block	O
.	O
</s>
<s>
Perl	B-Language
poetry	O
is	O
the	O
practice	O
of	O
writing	O
poems	O
that	O
can	O
be	O
compiled	B-Language
as	O
legal	O
Perl	B-Language
code	O
,	O
for	O
example	O
the	O
piece	O
known	O
as	O
Black	O
Perl	B-Language
.	O
</s>
<s>
Perl	B-Language
poetry	O
is	O
made	O
possible	O
by	O
the	O
large	O
number	O
of	O
English	O
words	O
that	O
are	O
used	O
in	O
the	O
Perl	B-Language
language	I-Language
.	O
</s>
<s>
New	O
poems	O
are	O
regularly	O
submitted	O
to	O
the	O
community	O
at	O
PerlMonks	B-Language
.	O
</s>
<s>
A	O
number	O
of	O
IRC	B-Protocol
channels	O
offer	O
support	O
for	O
Perl	B-Language
and	O
some	O
of	O
its	O
modules	B-Language
.	O
</s>
<s>
There	O
are	O
also	O
many	O
examples	O
of	O
code	O
written	O
purely	O
for	O
entertainment	O
on	O
the	O
CPAN	B-Language
.	O
</s>
<s>
Upon	O
execution	O
of	O
such	O
a	O
program	O
,	O
the	O
module	B-Language
translates	O
its	O
source	O
code	O
into	O
regular	O
Perl	B-Language
and	O
runs	O
it	O
.	O
</s>
<s>
The	O
Perl	B-Language
community	O
has	O
set	O
aside	O
the	O
"	O
Acme	O
"	O
namespace	O
for	O
modules	B-Language
that	O
are	O
fun	O
in	O
nature	O
(	O
but	O
its	O
scope	O
has	O
widened	O
to	O
include	O
exploratory	O
or	O
experimental	O
code	O
or	O
any	O
other	O
module	B-Language
that	O
is	O
not	O
meant	O
to	O
ever	O
be	O
used	O
in	O
production	O
)	O
.	O
</s>
<s>
Some	O
of	O
the	O
Acme	O
modules	B-Language
are	O
deliberately	O
implemented	O
in	O
amusing	O
ways	O
.	O
</s>
<s>
This	O
includes	O
Acme::Bleach	O
,	O
one	O
of	O
the	O
first	O
modules	B-Language
in	O
the	O
Acme::	O
namespace	O
,	O
which	O
allows	O
the	O
program	O
's	O
source	O
code	O
to	O
be	O
"	O
whitened	O
"	O
(	O
i.e.	O
,	O
all	O
characters	O
replaced	O
with	O
whitespace	O
)	O
and	O
yet	O
still	O
work	O
.	O
</s>
<s>
In	O
older	O
versions	O
of	O
Perl	B-Language
,	O
one	O
would	O
write	O
the	O
Hello	O
World	O
program	O
as	O
:	O
</s>
<s>
Here	O
is	O
a	O
more	O
complex	O
Perl	B-Language
program	O
,	O
that	O
counts	O
down	O
seconds	O
from	O
a	O
given	O
starting	O
value	O
:	O
</s>
<s>
The	O
Perl	B-Language
interpreter	I-Language
can	O
also	O
be	O
used	O
for	O
one-off	O
scripts	O
on	O
the	O
command	B-Application
line	I-Application
.	O
</s>
<s>
The	O
following	O
example	O
(	O
as	O
invoked	O
from	O
an	O
sh-compatible	O
shell	O
,	O
such	O
as	O
Bash	O
)	O
translates	O
the	O
string	O
"	O
Bob	O
"	O
in	O
all	O
files	O
ending	O
with	O
.txt	O
in	O
the	O
current	O
directory	O
to	O
"	O
Robert	O
"	O
:	O
</s>
<s>
Perl	B-Language
has	O
been	O
referred	O
to	O
as	O
"	O
line	O
noise	O
"	O
and	O
a	O
write-only	O
language	O
by	O
its	O
critics	O
.	O
</s>
<s>
The	O
earliest	O
such	O
mention	O
was	O
in	O
the	O
first	O
edition	O
of	O
the	O
book	O
Learning	O
Perl	B-Language
,	O
a	O
Perl	B-Language
4	O
tutorial	O
book	O
written	O
by	O
Randal	O
L	O
.	O
Schwartz	O
,	O
in	O
the	O
first	O
chapter	O
of	O
which	O
he	O
states	O
:	O
"	O
Yes	O
,	O
sometimes	O
Perl	B-Language
looks	O
like	O
line	O
noise	O
to	O
the	O
uninitiated	O
,	O
but	O
to	O
the	O
seasoned	O
Perl	B-Language
programmer	O
,	O
it	O
looks	O
like	O
checksummed	O
line	O
noise	O
with	O
a	O
mission	O
in	O
life.	O
"	O
</s>
<s>
He	O
also	O
stated	O
that	O
the	O
accusation	O
that	O
Perl	B-Language
is	O
a	O
write-only	O
language	O
could	O
be	O
avoided	O
by	O
coding	O
with	O
"	O
proper	O
care	O
"	O
.	O
</s>
<s>
The	O
Perl	B-Language
overview	O
document	O
states	O
that	O
the	O
names	O
of	O
built-in	O
"	O
magic	O
"	O
scalar	O
variables	O
"	O
look	O
like	O
punctuation	O
or	O
line	O
noise	O
"	O
.	O
</s>
<s>
However	O
,	O
the	O
English	O
module	B-Language
provides	O
both	O
long	O
and	O
short	O
English	O
alternatives	O
.	O
</s>
<s>
document	O
states	O
that	O
line	O
noise	O
in	O
regular	B-Language
expressions	I-Language
could	O
be	O
mitigated	O
using	O
the	O
/x	O
modifier	O
to	O
add	O
whitespace	O
.	O
</s>
<s>
According	O
to	O
the	O
Perl	B-Application
6	I-Application
FAQ	O
,	O
Perl	B-Application
6	I-Application
was	O
designed	O
to	O
mitigate	O
"	O
the	O
usual	O
suspects	O
"	O
that	O
elicit	O
the	O
"	O
line	O
noise	O
"	O
claim	O
from	O
Perl	B-Language
5	O
critics	O
,	O
including	O
the	O
removal	O
of	O
"	O
the	O
majority	O
of	O
the	O
punctuation	O
variables	O
"	O
and	O
the	O
sanitization	O
of	O
the	O
regex	B-Language
syntax	O
.	O
</s>
<s>
The	O
Perl	B-Application
6	I-Application
FAQ	O
also	O
states	O
that	O
what	O
is	O
sometimes	O
referred	O
to	O
as	O
Perl	B-Language
's	O
line	O
noise	O
is	O
"	O
the	O
actual	O
syntax	O
of	O
the	O
language	O
"	O
just	O
as	O
gerunds	O
and	O
prepositions	O
are	O
a	O
part	O
of	O
the	O
English	O
language	O
.	O
</s>
<s>
In	O
a	O
December	O
2012	O
blog	O
posting	O
,	O
despite	O
claiming	O
that	O
"	O
Rakudo	B-Language
Perl	I-Language
6	I-Language
has	O
failed	O
and	O
will	O
continue	O
to	O
fail	O
unless	O
it	O
gets	O
some	O
adult	O
supervision	O
"	O
,	O
chromatic	O
stated	O
that	O
the	O
design	O
of	O
Perl	B-Application
6	I-Application
has	O
a	O
"	O
well-defined	O
grammar	O
"	O
as	O
well	O
as	O
an	O
"	O
improved	O
type	O
system	O
,	O
a	O
unified	O
object	B-Language
system	I-Language
with	O
an	O
intelligent	O
metamodel	O
,	O
metaoperators	O
,	O
and	O
a	O
clearer	O
system	O
of	O
context	O
that	O
provides	O
for	O
such	O
niceties	O
as	O
pervasive	O
laziness	O
"	O
.	O
</s>
<s>
He	O
also	O
stated	O
that	O
"	O
Perl	B-Application
6	I-Application
has	O
a	O
coherence	O
and	O
a	O
consistency	O
that	O
Perl	B-Language
5	O
lacks.	O
"	O
</s>
