<s>
SETL	B-Language
(	O
SET	O
Language	O
)	O
is	O
a	O
very	B-Language
high-level	I-Language
programming	I-Language
language	I-Language
based	O
on	O
the	O
mathematical	O
theory	O
of	O
sets	O
.	O
</s>
<s>
SETL	B-Language
provides	O
two	O
basic	O
aggregate	O
data	O
types	O
:	O
unordered	O
sets	O
,	O
and	O
sequences	O
(	O
the	O
latter	O
also	O
called	O
tuples	O
)	O
.	O
</s>
<s>
Primitive	O
operations	O
in	O
SETL	B-Language
include	O
set	O
membership	O
,	O
union	O
,	O
intersection	O
,	O
and	O
power	O
set	O
construction	O
,	O
among	O
others	O
.	O
</s>
<s>
SETL	B-Language
provides	O
quantified	O
boolean	O
expressions	O
constructed	O
using	O
the	O
universal	O
and	O
existential	B-Algorithm
quantifiers	I-Algorithm
of	O
first-order	O
predicate	O
logic	O
.	O
</s>
<s>
SETL	B-Language
provides	O
several	O
iterators	O
to	O
produce	O
a	O
variety	O
of	O
loops	O
over	O
aggregate	O
data	O
structures	O
.	O
</s>
<s>
The	O
notation	O
is	O
similar	O
to	O
list	B-Language
comprehension	I-Language
.	O
</s>
<s>
A	O
more	O
conventional	O
SETL	B-Language
expression	O
for	O
factorial	O
(	O
n	O
>	O
0	O
)	O
:	O
</s>
<s>
Implementations	O
of	O
SETL	B-Language
were	O
available	O
on	O
the	O
DEC	B-Device
VAX	I-Device
,	O
IBM/370	B-Device
,	O
SUN	O
workstation	O
and	O
APOLLO	O
.	O
</s>
<s>
In	O
the	O
1970s	O
,	O
SETL	B-Language
was	O
ported	O
to	O
the	O
BESM-6	B-Device
,	O
ES	B-Device
EVM	I-Device
and	O
other	O
Russian	O
computer	O
systems	O
.	O
</s>
<s>
SETL	B-Language
was	O
used	O
for	O
an	O
early	O
implementation	O
of	O
the	O
programming	O
language	O
Ada	B-Language
,	O
named	O
the	O
NYU	O
Ada/ED	O
translator	O
.	O
</s>
<s>
This	O
later	O
became	O
the	O
first	O
validated	O
Ada	B-Language
implementation	O
,	O
certified	O
on	O
April	O
11	O
,	O
1983	O
.	O
</s>
<s>
According	O
to	O
Guido	O
van	O
Rossum	O
,	O
"	O
Python	B-Language
's	O
predecessor	O
,	O
ABC	B-Language
,	O
was	O
inspired	O
by	O
SETL	B-Language
--	O
Lambert	O
Meertens	O
spent	O
a	O
year	O
with	O
the	O
SETL	B-Language
group	O
at	O
NYU	O
before	O
coming	O
up	O
with	O
the	O
final	O
ABC	B-Language
design	O
!	O
"	O
</s>
<s>
SET	O
Language	O
2	O
(	O
SETL2	B-Language
)	O
,	O
a	O
backward	O
incompatible	O
descendant	O
of	O
SETL	B-Language
,	O
was	O
created	O
by	O
Kirk	O
Snyder	O
of	O
the	O
Courant	O
Institute	O
of	O
Mathematical	O
Sciences	O
at	O
New	O
York	O
University	O
in	O
the	O
late	O
1980s	O
.	O
</s>
<s>
Like	O
its	O
predecessor	O
,	O
it	O
is	O
based	O
on	O
the	O
theory	O
and	O
notation	O
of	O
finite	O
sets	O
,	O
but	O
has	O
also	O
been	O
influenced	O
in	O
syntax	O
and	O
style	O
by	O
the	O
Ada	B-Language
language	I-Language
.	O
</s>
<s>
Interactive	O
SET	O
Language	O
(	O
ISETL	B-Language
)	O
is	O
a	O
variant	O
of	O
SETL	B-Language
used	O
in	O
discrete	O
mathematics	O
.	O
</s>
<s>
is	O
a	O
command-line	O
utility	O
that	O
extends	O
and	O
implements	O
SETL	B-Language
.	O
</s>
