<s>
The	O
Compiler	B-Language
Language	I-Language
With	I-Language
No	I-Language
Pronounceable	I-Language
Acronym	I-Language
(	O
INTERCAL	B-Language
)	O
is	O
an	O
esoteric	O
programming	O
language	O
that	O
was	O
created	O
as	O
a	O
parody	O
by	O
Don	O
Woods	O
and	O
,	O
two	O
Princeton	O
University	O
students	O
,	O
in	O
1972	O
.	O
</s>
<s>
There	O
are	O
two	O
maintained	O
implementations	O
of	O
INTERCAL	B-Language
dialects	O
:	O
C-INTERCAL	O
(	O
created	O
in	O
1990	O
)	O
,	O
maintained	O
by	O
Eric	O
S	O
.	O
Raymond	O
and	O
Alex	O
Smith	O
,	O
and	O
CLC-INTERCAL	O
,	O
maintained	O
by	O
Claudio	O
Calvelli	O
.	O
</s>
<s>
The	O
original	O
Princeton	O
implementation	O
used	O
punched	B-Architecture
cards	I-Architecture
and	O
the	O
EBCDIC	B-Language
character	O
set	O
.	O
</s>
<s>
To	O
allow	O
INTERCAL	B-Language
to	O
run	O
on	O
computers	O
using	O
ASCII	B-Protocol
,	O
substitutions	O
for	O
two	O
characters	O
had	O
to	O
be	O
made	O
:	O
$	O
substituted	O
for	O
¢	O
as	O
the	O
mingle	O
operator	O
,	O
"represent[ing]	O
the	O
increasing	O
cost	O
of	O
software	O
in	O
relation	O
to	O
hardware	O
"	O
,	O
and	O
?	O
</s>
<s>
In	O
recent	O
versions	O
of	O
C-INTERCAL	O
,	O
the	O
older	O
operators	O
are	O
supported	O
as	O
alternatives	O
;	O
INTERCAL	B-Language
programs	O
may	O
now	O
be	O
encoded	O
in	O
ASCII	B-Protocol
,	O
Latin-1	O
,	O
or	O
UTF-8	O
.	O
</s>
<s>
C-INTERCAL	O
swaps	O
the	O
major	O
and	O
minor	O
version	O
numbers	O
,	O
compared	O
to	O
tradition	O
.	O
</s>
<s>
CLC-INTERCAL	O
version	O
numbering	O
scheme	O
was	O
traditional	O
until	O
version	O
0.06	O
,	O
when	O
it	O
changed	O
to	O
the	O
scheme	O
documented	O
in	O
the	O
README	O
file	O
,	O
which	O
says	O
:	O
</s>
<s>
INTERCAL	B-Language
was	O
intended	O
to	O
be	O
completely	O
different	O
from	O
all	O
other	O
computer	O
languages	O
.	O
</s>
<s>
Common	O
operations	O
in	O
other	O
languages	O
have	O
cryptic	O
and	O
redundant	O
syntax	O
in	O
INTERCAL	B-Language
.	O
</s>
<s>
From	O
the	O
INTERCAL	B-Language
Reference	O
Manual	O
:	O
</s>
<s>
INTERCAL	B-Language
has	O
many	O
other	O
features	O
designed	O
to	O
make	O
it	O
even	O
more	O
aesthetically	O
unpleasing	O
to	O
the	O
programmer	O
:	O
it	O
uses	O
statements	O
such	O
as	O
"	O
READ	O
OUT	O
"	O
,	O
"	O
IGNORE	O
"	O
,	O
"	O
FORGET	O
"	O
,	O
and	O
modifiers	O
such	O
as	O
"	O
PLEASE	O
"	O
.	O
</s>
<s>
Although	O
this	O
feature	O
existed	O
in	O
the	O
original	O
INTERCAL	B-Language
compiler	O
,	O
it	O
was	O
undocumented	O
.	O
</s>
<s>
Despite	O
the	O
language	O
's	O
intentionally	O
obtuse	O
and	O
wordy	O
syntax	O
,	O
INTERCAL	B-Language
is	O
nevertheless	O
Turing-complete	O
:	O
given	O
enough	O
memory	O
,	O
INTERCAL	B-Language
can	O
solve	O
any	O
problem	O
that	O
a	O
Universal	O
Turing	O
machine	O
can	O
solve	O
.	O
</s>
<s>
Most	O
implementations	O
of	O
INTERCAL	B-Language
do	O
this	O
very	O
slowly	O
,	O
however	O
.	O
</s>
<s>
A	O
Sieve	B-Algorithm
of	I-Algorithm
Eratosthenes	I-Algorithm
benchmark	O
,	O
computing	O
all	O
prime	O
numbers	O
less	O
than	O
65536	O
,	O
was	O
tested	O
on	O
a	O
Sun	O
SPARCstation	B-Architecture
1	I-Architecture
in	O
1992	O
.	O
</s>
<s>
In	O
C	B-Language
,	O
it	O
took	O
less	O
than	O
half	O
a	O
second	O
;	O
the	O
same	O
program	O
in	O
INTERCAL	B-Language
took	O
over	O
seventeen	O
hours	O
.	O
</s>
<s>
The	O
INTERCAL	B-Language
Reference	O
Manual	O
contains	O
many	O
paradoxical	O
,	O
nonsensical	O
,	O
or	O
otherwise	O
humorous	O
instructions	O
:	O
</s>
<s>
The	O
manual	O
also	O
contains	O
a	O
"	O
tonsil	O
"	O
,	O
as	O
explained	O
in	O
this	O
footnote	O
:	O
"	O
4	O
)	O
Since	O
all	O
other	O
reference	O
manuals	O
have	O
appendices	O
,	O
it	O
was	O
decided	O
that	O
the	O
INTERCAL	B-Language
manual	O
should	O
contain	O
some	O
other	O
type	O
of	O
removable	O
organ.	O
"	O
</s>
<s>
The	O
INTERCAL	B-Language
manual	O
gives	O
unusual	O
names	O
to	O
all	O
non-alphanumeric	O
ASCII	B-Protocol
characters	I-Protocol
:	O
single	O
and	O
double	O
quotes	O
are	O
"	O
sparks	O
"	O
and	O
"	O
rabbit	O
ears	O
"	O
respectively	O
.	O
</s>
<s>
The	O
assignment	O
operator	O
,	O
represented	O
as	O
an	O
equals	O
sign	O
(	O
INTERCAL	B-Language
's	O
"	O
half	O
mesh	O
"	O
)	O
in	O
many	O
other	O
programming	O
languages	O
,	O
is	O
in	O
INTERCAL	B-Language
a	O
left-arrow	O
,	O
<-	O
,	O
made	O
up	O
of	O
an	O
"	O
angle	O
"	O
and	O
a	O
"	O
worm	O
"	O
,	O
obviously	O
read	O
as	O
"	O
gets	O
"	O
.	O
</s>
<s>
Input	O
(	O
using	O
the	O
WRITE	O
IN	O
instruction	O
)	O
and	O
output	O
(	O
using	O
the	O
READ	O
OUT	O
instruction	O
)	O
do	O
not	O
use	O
the	O
usual	O
formats	O
;	O
in	O
INTERCAL-72	O
,	O
WRITE	O
IN	O
inputs	O
a	O
number	O
written	O
out	O
as	O
digits	O
in	O
English	O
(	O
such	O
as	O
SIX	O
FIVE	O
FIVE	O
THREE	O
FIVE	O
)	O
,	O
and	O
READ	O
OUT	O
outputs	O
it	O
in	O
"	O
butchered	O
"	O
Roman	O
numerals	O
.	O
</s>
<s>
More	O
recent	O
versions	O
have	O
their	O
own	O
I/O	B-General_Concept
systems	O
.	O
</s>
<s>
INTERCAL-72	O
(	O
the	O
original	O
version	O
of	O
INTERCAL	B-Language
)	O
had	O
only	O
four	O
data	O
types	O
:	O
the	O
16-bit	O
integer	O
(	O
represented	O
with	O
a	O
.	O
,	O
called	O
a	O
"	O
spot	O
"	O
)	O
,	O
the	O
32-bit	O
integer	O
(	O
:	O
,	O
a	O
"	O
twospot	O
"	O
)	O
,	O
the	O
array	O
of	O
16-bit	O
integers	O
(	O
,,	O
a	O
"	O
tail	O
"	O
)	O
,	O
and	O
the	O
array	O
of	O
32-bit	O
integers	O
(;	O
,	O
a	O
"	O
hybrid	O
"	O
)	O
.	O
</s>
<s>
However	O
,	O
each	O
of	O
these	O
variables	O
has	O
its	O
own	O
stack	B-Application
on	O
which	O
it	O
can	O
be	O
pushed	O
and	O
popped	O
(	O
STASHed	O
and	O
RETRIEVEd	O
,	O
in	O
INTERCAL	B-Language
terminology	O
)	O
,	O
increasing	O
the	O
possible	O
complexity	O
of	O
data	O
structures	O
.	O
</s>
<s>
More	O
modern	O
versions	O
of	O
INTERCAL	B-Language
have	O
by	O
and	O
large	O
kept	O
the	O
same	O
data	O
structures	O
,	O
with	O
appropriate	O
modifications	O
;	O
TriINTERCAL	O
,	O
which	O
modifies	O
the	O
radix	O
with	O
which	O
numbers	O
are	O
represented	O
,	O
can	O
use	O
a	O
10-trit	O
type	O
rather	O
than	O
a	O
16-bit	O
type	O
,	O
and	O
CLC-INTERCAL	O
implements	O
many	O
of	O
its	O
own	O
data	O
structures	O
,	O
such	O
as	O
"	O
classes	O
and	O
lectures	O
"	O
,	O
by	O
making	O
the	O
basic	O
data	O
types	O
store	O
more	O
information	O
rather	O
than	O
adding	O
new	O
types	O
.	O
</s>
<s>
Constants	O
can	O
also	O
be	O
used	O
,	O
and	O
are	O
represented	O
by	O
a	O
#	O
(	O
"	O
mesh	O
"	O
)	O
followed	O
by	O
the	O
constant	O
itself	O
,	O
written	O
as	O
a	O
decimal	B-Application
number	O
;	O
only	O
integer	O
constants	O
from	O
0	O
to	O
65535	O
are	O
supported	O
.	O
</s>
<s>
There	O
are	O
only	O
five	O
operators	O
in	O
INTERCAL-72	O
.	O
</s>
<s>
one	O
character	O
later	O
than	O
it	O
would	O
be	O
in	O
programming	O
languages	O
like	O
C	B-Language
.	O
)	O
SELECT	O
and	O
INTERLEAVE	O
(	O
which	O
is	O
also	O
known	O
as	O
MINGLE	O
)	O
are	O
infix	O
binary	O
operators	O
;	O
SELECT	O
takes	O
the	O
bits	O
of	O
its	O
first	O
operand	O
that	O
correspond	O
to	O
"	O
1	O
"	O
bits	O
of	O
its	O
second	O
operand	O
and	O
removes	O
the	O
bits	O
that	O
correspond	O
to	O
"	O
0	O
"	O
bits	O
,	O
shifting	O
towards	O
the	O
least	O
significant	O
bit	O
and	O
padding	O
with	O
zeroes	O
(	O
so	O
51	O
(	O
110011	O
in	O
binary	O
)	O
SELECT	O
21	O
(	O
10101	O
in	O
binary	O
)	O
is	O
5	O
(	O
101	O
in	O
binary	O
)	O
)	O
;	O
MINGLE	O
alternates	O
bits	O
from	O
its	O
first	O
and	O
second	O
operands	O
(	O
in	O
such	O
a	O
way	O
that	O
the	O
least	O
significant	O
bit	O
of	O
its	O
second	O
operand	O
is	O
the	O
least	O
significant	O
bit	O
of	O
the	O
result	O
)	O
.	O
</s>
<s>
INTERCAL	B-Language
statements	O
all	O
start	O
with	O
a	O
"	O
statement	O
identifier	O
"	O
;	O
in	O
INTERCAL-72	O
,	O
this	O
can	O
be	O
DO	O
,	O
PLEASE	O
,	O
or	O
PLEASE	O
DO	O
,	O
all	O
of	O
which	O
mean	O
the	O
same	O
to	O
the	O
program	O
(	O
but	O
using	O
one	O
of	O
these	O
too	O
heavily	O
causes	O
the	O
program	O
to	O
be	O
rejected	O
,	O
an	O
undocumented	B-General_Concept
feature	I-General_Concept
in	O
INTERCAL-72	O
that	O
was	O
mentioned	O
in	O
the	O
C-INTERCAL	O
manual	O
)	O
,	O
or	O
an	O
inverted	O
form	O
(	O
with	O
NOT	O
or	O
N'T	O
appended	O
to	O
the	O
identifier	O
)	O
.	O
</s>
<s>
Backtracking	O
INTERCAL	B-Language
,	O
a	O
modern	O
variant	O
,	O
also	O
allows	O
variants	O
using	O
MAYBE	O
(	O
possibly	O
combined	O
with	O
PLEASE	O
or	O
DO	O
)	O
as	O
a	O
statement	O
identifier	O
,	O
which	O
introduces	O
a	O
choice-point	O
.	O
</s>
<s>
In	O
INTERCAL-72	O
,	O
the	O
main	O
control	O
structures	O
are	O
NEXT	O
,	O
RESUME	O
,	O
and	O
FORGET	O
.	O
</s>
<s>
DO	O
(	O
line	O
)	O
NEXT	O
branches	O
to	O
the	O
line	O
specified	O
,	O
remembering	O
the	O
next	O
line	O
that	O
would	O
be	O
executed	O
if	O
it	O
were	O
n't	O
for	O
the	O
NEXT	O
on	O
a	O
call	O
stack	B-Application
(	O
other	O
identifiers	O
than	O
DO	O
can	O
be	O
used	O
on	O
any	O
statement	O
,	O
DO	O
is	O
given	O
as	O
an	O
example	O
)	O
;	O
DO	O
FORGET	O
expression	O
removes	O
expression	O
entries	O
from	O
the	O
top	O
of	O
the	O
call	O
stack	B-Application
(	O
this	O
is	O
useful	O
to	O
avoid	O
the	O
error	O
that	O
otherwise	O
happens	O
when	O
there	O
are	O
more	O
than	O
80	O
entries	O
)	O
,	O
and	O
DO	O
RESUME	O
expression	O
removes	O
expression	O
entries	O
from	O
the	O
call	O
stack	B-Application
and	O
jumps	O
to	O
the	O
last	O
line	O
remembered	O
.	O
</s>
<s>
C-INTERCAL	O
also	O
provides	O
the	O
COME	B-Language
FROM	I-Language
instruction	O
,	O
written	O
DO	O
COME	B-Language
FROM	I-Language
(	O
line	O
)	O
;	O
CLC-INTERCAL	O
and	O
the	O
most	O
recent	O
C-INTERCAL	O
versions	O
also	O
provide	O
computed	O
COME	B-Language
FROM	I-Language
(	O
DO	O
COME	B-Language
FROM	I-Language
expression	O
)	O
and	O
NEXT	O
FROM	O
,	O
which	O
is	O
like	O
COME	B-Language
FROM	I-Language
but	O
also	O
saves	O
a	O
return	O
address	O
on	O
the	O
NEXT	O
STACK	B-Application
.	O
</s>
<s>
Alternative	O
ways	O
to	O
affect	O
program	O
flow	O
,	O
originally	O
available	O
in	O
INTERCAL-72	O
,	O
are	O
to	O
use	O
the	O
IGNORE	O
and	O
REMEMBER	O
instructions	O
on	O
variables	O
(	O
which	O
cause	O
writes	O
to	O
the	O
variable	O
to	O
be	O
silently	O
ignored	O
and	O
to	O
take	O
effect	O
again	O
,	O
so	O
that	O
instructions	O
can	O
be	O
disabled	O
by	O
causing	O
them	O
to	O
have	O
no	O
effect	O
)	O
,	O
and	O
the	O
ABSTAIN	O
and	O
REINSTATE	O
instructions	O
on	O
lines	O
or	O
on	O
types	O
of	O
statement	O
,	O
causing	O
the	O
lines	O
to	O
have	O
no	O
effect	O
or	O
to	O
have	O
an	O
effect	O
again	O
respectively	O
.	O
</s>
<s>
program	O
demonstrates	O
how	O
different	O
INTERCAL	B-Language
is	O
from	O
standard	O
programming	O
languages	O
.	O
</s>
<s>
In	O
C	B-Language
,	O
it	O
could	O
read	O
as	O
follows	O
:	O
</s>
<s>
The	O
equivalent	O
program	O
in	O
C-INTERCAL	O
is	O
longer	O
and	O
harder	O
to	O
read	O
:	O
</s>
<s>
The	O
original	O
Woods	O
–	O
Lyon	O
INTERCAL	B-Language
was	O
very	O
limited	O
in	O
its	O
input/output	B-General_Concept
capabilities	O
:	O
the	O
only	O
acceptable	O
input	O
were	O
numbers	O
with	O
the	O
digits	O
spelled	O
out	O
,	O
and	O
the	O
only	O
output	O
was	O
an	O
extended	O
version	O
of	O
Roman	O
numerals	O
.	O
</s>
<s>
The	O
C-INTERCAL	O
reimplementation	O
,	O
being	O
available	O
on	O
the	O
Internet	O
,	O
has	O
made	O
the	O
language	O
more	O
popular	O
with	O
devotees	O
of	O
esoteric	O
programming	O
languages	O
.	O
</s>
<s>
The	O
C-INTERCAL	O
dialect	O
has	O
a	O
few	O
differences	O
from	O
original	O
INTERCAL	B-Language
and	O
introduced	O
a	O
few	O
new	O
features	O
,	O
such	O
as	O
a	O
COME	B-Language
FROM	I-Language
statement	O
and	O
a	O
means	O
of	O
doing	O
text	O
I/O	B-General_Concept
based	O
on	O
the	O
Turing	O
Text	O
Model	O
.	O
</s>
<s>
The	O
authors	O
of	O
C-INTERCAL	O
also	O
created	O
the	O
TriINTERCAL	O
variant	O
,	O
based	O
on	O
the	O
Ternary	B-Algorithm
numeral	I-Algorithm
system	I-Algorithm
and	O
generalizing	O
INTERCAL	B-Language
's	O
set	O
of	O
operators	O
.	O
</s>
<s>
A	O
more	O
recent	O
variant	O
is	O
Threaded	O
Intercal	B-Language
,	O
which	O
extends	O
the	O
functionality	O
of	O
COME	B-Language
FROM	I-Language
to	O
support	O
multithreading	B-Operating_System
.	O
</s>
<s>
CLC-INTERCAL	O
has	O
a	O
library	O
called	O
INTERNET	O
for	O
networking	O
functionality	O
including	O
being	O
an	O
INTERCAL	B-Language
server	O
,	O
and	O
also	O
includes	O
features	O
such	O
as	O
Quantum	O
Intercal	B-Language
,	O
which	O
enables	O
multi-value	O
calculations	O
in	O
a	O
way	O
purportedly	O
ready	O
for	O
the	O
first	O
quantum	O
computers	O
.	O
</s>
<s>
In	O
early	O
2017	O
a	O
.NET	B-Application
Implementation	O
targeting	O
the	O
.NET	B-Application
Framework	I-Application
appeared	O
on	O
GitHub	B-Application
.	O
</s>
<s>
In	O
the	O
article	O
"	O
A	O
Box	O
,	O
Darkly	O
:	O
Obfuscation	O
,	O
Weird	O
Languages	O
,	O
and	O
Code	O
Aesthetics	O
"	O
,	O
INTERCAL	B-Language
is	O
described	O
under	O
the	O
heading	O
"	O
Abandon	O
all	O
sanity	O
,	O
ye	O
who	O
enter	O
here	O
:	O
INTERCAL	B-Language
"	O
.	O
</s>
<s>
In	O
"	O
Technomasochism	O
"	O
,	O
Lev	O
Bratishenko	O
characterizes	O
the	O
INTERCAL	B-Language
compiler	O
as	O
a	O
dominatrix	O
:	O
</s>
<s>
The	O
Nitrome	O
Enjoyment	O
System	O
,	O
a	O
fictional	O
video	O
game	O
console	O
created	O
by	O
British	O
indie	O
game	O
developer	O
Nitrome	O
,	O
has	O
games	O
which	O
are	O
programmed	O
in	O
INTERCAL	B-Language
.	O
</s>
