<s>
In	O
computer	B-General_Concept
programming	I-General_Concept
,	O
an	O
enumerated	B-Language
type	I-Language
(	O
also	O
called	O
enumeration	B-Language
,	O
enum	B-Language
,	O
or	O
factor	O
in	O
the	O
R	B-Language
programming	I-Language
language	I-Language
,	O
and	O
a	O
categorical	O
variable	O
in	O
statistics	O
)	O
is	O
a	O
data	O
type	O
consisting	O
of	O
a	O
set	O
of	O
named	O
values	O
called	O
elements	O
,	O
members	O
,	O
enumeral	O
,	O
or	O
enumerators	O
of	O
the	O
type	O
.	O
</s>
<s>
An	O
enumerated	B-Language
type	I-Language
can	O
be	O
seen	O
as	O
a	O
degenerate	O
tagged	B-Language
union	I-Language
of	O
unit	O
type	O
.	O
</s>
<s>
A	O
variable	O
that	O
has	O
been	O
declared	O
as	O
having	O
an	O
enumerated	B-Language
type	I-Language
can	O
be	O
assigned	O
any	O
of	O
the	O
enumerators	O
as	O
a	O
value	O
.	O
</s>
<s>
In	O
other	O
words	O
,	O
an	O
enumerated	B-Language
type	I-Language
has	O
values	O
that	O
are	O
different	O
from	O
each	O
other	O
,	O
and	O
that	O
can	O
be	O
compared	O
and	O
assigned	O
,	O
but	O
are	O
not	O
specified	O
by	O
the	O
programmer	O
as	O
having	O
any	O
particular	O
concrete	O
representation	O
in	O
the	O
computer	O
's	O
memory	O
;	O
compilers	O
and	O
interpreters	O
can	O
represent	O
them	O
arbitrarily	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
four	O
suits	O
in	O
a	O
deck	O
of	O
playing	O
cards	O
may	O
be	O
four	O
enumerators	O
named	O
Club	O
,	O
Diamond	O
,	O
Heart	O
,	O
and	O
Spade	O
,	O
belonging	O
to	O
an	O
enumerated	B-Language
type	I-Language
named	O
suit	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
enumerated	B-Language
type	I-Language
called	O
color	O
may	O
be	O
defined	O
to	O
consist	O
of	O
the	O
enumerators	O
Red	O
,	O
Green	O
,	O
Zebra	O
,	O
Missing	O
,	O
and	O
Bacon	O
.	O
</s>
<s>
In	O
some	O
languages	O
,	O
the	O
declaration	O
of	O
an	O
enumerated	B-Language
type	I-Language
also	O
intentionally	O
defines	O
an	O
ordering	O
of	O
its	O
members	O
(	O
High	O
,	O
Medium	O
and	O
Low	O
priorities	O
)	O
;	O
in	O
others	O
,	O
the	O
enumerators	O
are	O
unordered	O
(	O
English	O
,	O
French	O
,	O
German	O
and	O
Spanish	O
supported	O
languages	O
)	O
;	O
in	O
others	O
still	O
,	O
an	O
implicit	O
ordering	O
arises	O
from	O
the	O
compiler	O
concretely	O
representing	O
enumerators	O
as	O
integers	O
.	O
</s>
<s>
The	O
Boolean	O
type	O
,	O
for	O
example	O
is	O
often	O
a	O
pre-defined	O
enumeration	B-Language
of	O
the	O
values	O
False	O
and	O
True	O
.	O
</s>
<s>
Many	O
languages	O
allow	O
users	O
to	O
define	O
new	O
enumerated	B-Language
types	I-Language
.	O
</s>
<s>
Values	O
and	O
variables	O
of	O
an	O
enumerated	B-Language
type	I-Language
are	O
usually	O
implemented	O
with	O
some	O
integer	O
type	O
as	O
the	O
underlying	O
representation	O
.	O
</s>
<s>
Some	O
languages	O
,	O
especially	O
system	B-Language
programming	I-Language
languages	I-Language
,	O
allow	O
the	O
user	O
to	O
specify	O
the	O
bit	O
combination	O
to	O
be	O
used	O
for	O
each	O
enumerator	O
,	O
which	O
can	O
be	O
useful	O
to	O
efficiently	O
represent	O
sets	O
of	O
enumerators	O
as	O
fixed-length	O
bit	B-Data_Structure
strings	I-Data_Structure
.	O
</s>
<s>
In	O
type	O
theory	O
,	O
enumerated	B-Language
types	I-Language
are	O
often	O
regarded	O
as	O
tagged	B-Language
unions	I-Language
of	O
unit	O
types	O
.	O
</s>
<s>
Some	O
early	O
programming	O
languages	O
did	O
not	O
originally	O
have	O
enumerated	B-Language
types	I-Language
.	O
</s>
<s>
Other	O
techniques	O
assigned	O
arbitrary	O
values	O
to	O
strings	B-Language
containing	O
the	O
names	O
of	O
the	O
enumerators	O
.	O
</s>
<s>
Enumerated	B-Language
types	I-Language
,	O
on	O
the	O
other	O
hand	O
,	O
make	O
the	O
code	O
more	O
self-documenting	O
.	O
</s>
<s>
These	O
values	O
may	O
not	O
even	O
be	O
visible	O
to	O
the	O
programmer	O
(	O
see	O
information	B-Application
hiding	I-Application
)	O
.	O
</s>
<s>
Enumerated	B-Language
types	I-Language
can	O
also	O
prevent	O
a	O
programmer	O
from	O
writing	O
illogical	O
code	O
such	O
as	O
performing	O
mathematical	O
operations	O
on	O
the	O
values	O
of	O
the	O
enumerators	O
.	O
</s>
<s>
A	O
further	O
advantage	O
is	O
that	O
enumerated	B-Language
types	I-Language
can	O
allow	O
compilers	O
to	O
enforce	O
semantic	O
correctness	O
.	O
</s>
<s>
Conceptually	O
,	O
an	O
enumerated	B-Language
type	I-Language
is	O
similar	O
to	O
a	O
list	O
of	O
nominals	O
(	O
numeric	O
codes	O
)	O
,	O
since	O
each	O
possible	O
value	O
of	O
the	O
type	O
is	O
assigned	O
a	O
distinctive	O
natural	O
number	O
.	O
</s>
<s>
A	O
given	O
enumerated	B-Language
type	I-Language
is	O
thus	O
a	O
concrete	O
implementation	O
of	O
this	O
notion	O
.	O
</s>
<s>
When	O
order	O
is	O
meaningful	O
and/or	O
used	O
for	O
comparison	O
,	O
then	O
an	O
enumerated	B-Language
type	I-Language
becomes	O
an	O
ordinal	B-Language
type	O
.	O
</s>
<s>
Programming	O
languages	O
tend	O
to	O
have	O
their	O
own	O
,	O
oftentimes	O
multiple	O
,	O
programming	B-Language
styles	I-Language
and	O
naming	O
conventions	O
.	O
</s>
<s>
The	O
variable	O
assigned	O
to	O
an	O
enumeration	B-Language
is	O
usually	O
a	O
noun	O
in	O
singular	O
form	O
,	O
and	O
frequently	O
follows	O
either	O
a	O
PascalCase	O
or	O
uppercase	O
convention	O
,	O
while	O
lowercase	O
and	O
others	O
are	O
seen	O
less	O
frequently	O
.	O
</s>
<s>
In	O
Pascal	B-Application
,	O
an	O
enumerated	B-Language
type	I-Language
can	O
be	O
implicitly	O
declared	O
by	O
listing	O
the	O
values	O
in	O
a	O
parenthesised	O
list	O
:	O
</s>
<s>
The	O
order	O
in	O
which	O
the	O
enumeration	B-Language
values	O
are	O
given	O
matters	O
.	O
</s>
<s>
An	O
enumerated	B-Language
type	I-Language
is	O
an	O
ordinal	B-Language
type	O
,	O
and	O
the	O
pred	O
and	O
succ	O
functions	O
will	O
give	O
the	O
prior	O
or	O
next	O
value	O
of	O
the	O
enumeration	B-Language
,	O
and	O
ord	O
can	O
convert	O
enumeration	B-Language
values	O
to	O
their	O
integer	O
representation	O
.	O
</s>
<s>
Standard	O
Pascal	B-Application
does	O
not	O
offer	O
a	O
conversion	O
from	O
arithmetic	O
types	O
to	O
enumerations	B-Language
,	O
however	O
.	O
</s>
<s>
Extended	O
Pascal	B-Application
offers	O
this	O
functionality	O
via	O
an	O
extended	O
succ	O
function	O
.	O
</s>
<s>
Some	O
other	O
Pascal	B-Application
dialects	O
allow	O
it	O
via	O
type-casts	O
.	O
</s>
<s>
Some	O
modern	O
descendants	O
of	O
Pascal	B-Application
,	O
such	O
as	O
Modula-3	B-Language
,	O
provide	O
a	O
special	O
conversion	O
syntax	O
using	O
a	O
method	O
called	O
VAL	O
;	O
Modula-3	B-Language
also	O
treats	O
BOOLEAN	O
and	O
CHAR	O
as	O
special	O
pre-defined	O
enumerated	B-Language
types	I-Language
and	O
uses	O
ORD	O
and	O
VAL	O
for	O
standard	O
ASCII	B-Protocol
decoding	O
and	O
encoding	O
.	O
</s>
<s>
Pascal	B-Application
style	O
languages	O
also	O
allow	O
enumeration	B-Language
to	O
be	O
used	O
as	O
array	O
index	O
:	O
</s>
<s>
In	O
Ada	B-Language
,	O
the	O
use	O
of	O
"	O
=	O
"	O
was	O
replaced	O
with	O
"	O
is	O
"	O
leaving	O
the	O
definition	O
quite	O
similar	O
:	O
</s>
<s>
In	O
addition	O
to	O
Pred	O
,	O
Succ	O
,	O
Val	O
and	O
Pos	O
Ada	B-Language
also	O
supports	O
simple	O
string	O
conversions	O
via	O
Image	O
and	O
Value	O
.	O
</s>
<s>
Similar	O
to	O
C-style	O
languages	O
Ada	B-Language
allows	O
the	O
internal	O
representation	O
of	O
the	O
enumeration	B-Language
to	O
be	O
specified	O
:	O
</s>
<s>
Unlike	O
C-style	O
languages	O
Ada	B-Language
also	O
allows	O
the	O
number	O
of	O
bits	O
of	O
the	O
enumeration	B-Language
to	O
be	O
specified	O
:	O
</s>
<s>
Like	O
Modula-3	B-Language
Ada	B-Language
treats	O
Boolean	O
and	O
Character	O
as	O
special	O
pre-defined	O
(	O
in	O
package	O
"	O
Standard	O
"	O
)	O
enumerated	B-Language
types	I-Language
.	O
</s>
<s>
Unlike	O
Modula-3	B-Language
one	O
can	O
also	O
define	O
own	O
character	O
types	O
:	O
</s>
<s>
The	O
original	O
K&R	O
dialect	O
of	O
the	O
programming	B-Language
language	I-Language
C	I-Language
had	O
no	O
enumerated	B-Language
types	I-Language
.	O
</s>
<s>
In	O
C	B-Language
,	O
enumerations	B-Language
are	O
created	O
by	O
explicit	O
definitions	O
(	O
the	O
enum	B-Language
keyword	O
by	O
itself	O
does	O
not	O
cause	O
allocation	O
of	O
storage	O
)	O
which	O
use	O
the	O
enum	B-Language
keyword	O
and	O
are	O
reminiscent	O
of	O
struct	B-Application
and	O
union	O
definitions	O
:	O
</s>
<s>
C	B-Language
exposes	O
the	O
integer	O
representation	O
of	O
enumeration	B-Language
values	O
directly	O
to	O
the	O
programmer	O
.	O
</s>
<s>
Integers	O
and	O
enum	B-Language
values	O
can	O
be	O
mixed	O
freely	O
,	O
and	O
all	O
arithmetic	O
operations	O
on	O
enum	B-Language
values	O
are	O
permitted	O
.	O
</s>
<s>
It	O
is	O
even	O
possible	O
for	O
an	O
enum	B-Language
variable	O
to	O
hold	O
an	O
integer	O
that	O
does	O
not	O
represent	O
any	O
of	O
the	O
enumeration	B-Language
values	O
.	O
</s>
<s>
In	O
fact	O
,	O
according	O
to	O
the	O
language	O
definition	O
,	O
the	O
above	O
code	O
will	O
define	O
Clubs	O
,	O
Diamonds	O
,	O
Hearts	O
,	O
and	O
Spades	O
as	O
constants	O
of	O
type	O
int	O
,	O
which	O
will	O
only	O
be	O
converted	O
(	O
silently	O
)	O
to	O
enum	B-Language
cardsuit	O
if	O
they	O
are	O
stored	O
in	O
a	O
variable	O
of	O
that	O
type	O
.	O
</s>
<s>
C	B-Language
also	O
allows	O
the	O
programmer	O
to	O
choose	O
the	O
values	O
of	O
the	O
enumeration	B-Language
constants	O
explicitly	O
,	O
even	O
without	O
type	O
.	O
</s>
<s>
could	O
be	O
used	O
to	O
define	O
a	O
type	O
that	O
allows	O
mathematical	O
sets	O
of	O
suits	O
to	O
be	O
represented	O
as	O
an	O
enum	B-Language
cardsuit	O
by	O
bitwise	O
logic	O
operations	O
.	O
</s>
<s>
Since	O
C23	B-Language
,	O
the	O
underlying	O
type	O
of	O
an	O
enumeration	B-Language
can	O
be	O
specified	O
by	O
the	O
programmer	O
:	O
</s>
<s>
Enumerated	B-Language
types	I-Language
in	O
the	O
C#	B-Application
programming	O
language	O
preserve	O
most	O
of	O
the	O
"	O
small	O
integer	O
"	O
semantics	O
of	O
C	B-Language
's	O
enums	B-Language
.	O
</s>
<s>
Some	O
arithmetic	O
operations	O
are	O
not	O
defined	O
for	O
enums	B-Language
,	O
but	O
an	O
enum	B-Language
value	O
can	O
be	O
explicitly	O
converted	O
to	O
an	O
integer	O
and	O
back	O
again	O
,	O
and	O
an	O
enum	B-Language
variable	O
can	O
have	O
values	O
that	O
were	O
not	O
declared	O
by	O
the	O
enum	B-Language
definition	O
.	O
</s>
<s>
C#	B-Application
also	O
provides	O
the	O
C-like	O
feature	O
of	O
being	O
able	O
to	O
define	O
specific	O
integer	O
values	O
for	O
enumerations	B-Language
.	O
</s>
<s>
By	O
doing	O
this	O
it	O
is	O
possible	O
to	O
perform	O
binary	O
operations	O
on	O
enumerations	B-Language
,	O
thus	O
treating	O
enumeration	B-Language
values	O
as	O
sets	O
of	O
flags	O
.	O
</s>
<s>
These	O
flags	O
can	O
be	O
tested	O
using	O
binary	O
operations	O
or	O
with	O
the	O
Enum	B-Language
type	O
's	O
builtin	O
'	O
HasFlag	O
 '	O
method	O
.	O
</s>
<s>
The	O
enumeration	B-Language
definition	O
defines	O
names	O
for	O
the	O
selected	O
integer	O
values	O
and	O
is	O
syntactic	O
sugar	O
,	O
as	O
it	O
is	O
possible	O
to	O
assign	O
to	O
an	O
enum	B-Language
variable	O
other	O
integer	O
values	O
that	O
are	O
not	O
in	O
the	O
scope	O
of	O
the	O
enum	B-Language
definition	O
.	O
</s>
<s>
C++	B-Language
has	O
enumeration	B-Language
types	O
that	O
are	O
directly	O
inherited	O
from	O
C	B-Language
's	O
and	O
work	O
mostly	O
like	O
these	O
,	O
except	O
that	O
an	O
enumeration	B-Language
is	O
a	O
real	O
type	O
in	O
C++	B-Language
,	O
giving	O
added	O
compile-time	O
checking	O
.	O
</s>
<s>
Also	O
(	O
as	O
with	O
structs	B-Application
)	O
,	O
the	O
C++	B-Language
enum	B-Language
keyword	O
is	O
combined	O
with	O
a	O
,	O
so	O
that	O
instead	O
of	O
naming	O
the	O
type	O
enum	B-Language
name	O
,	O
simply	O
name	O
it	O
name	O
.	O
</s>
<s>
This	O
can	O
be	O
simulated	O
in	O
C	B-Language
using	O
a	O
typedef	B-Language
:	O
</s>
<s>
C++11	B-Language
also	O
provides	O
a	O
second	O
kind	O
of	O
enumeration	B-Language
,	O
called	O
a	O
scoped	O
enumeration	B-Language
.	O
</s>
<s>
Among	O
other	O
things	O
,	O
this	O
allows	O
I/O	O
streaming	O
to	O
be	O
defined	O
for	O
the	O
enumeration	B-Language
type	O
.	O
</s>
<s>
Another	O
feature	O
of	O
scoped	O
enumerations	B-Language
is	O
that	O
the	O
enumerators	O
do	O
not	O
leak	O
,	O
so	O
usage	O
requires	O
prefixing	O
with	O
the	O
name	O
of	O
the	O
enumeration	B-Language
(	O
e.g.	O
,	O
Color::Red	O
for	O
the	O
first	O
enumerator	O
in	O
the	O
example	O
below	O
)	O
,	O
unless	O
a	O
using	O
enum	B-Language
declaration	O
(	O
introduced	O
in	O
C++20	B-Language
)	O
has	O
been	O
used	O
to	O
bring	O
the	O
enumerators	O
into	O
the	O
current	O
scope	O
.	O
</s>
<s>
A	O
scoped	O
enumeration	B-Language
is	O
specified	O
by	O
the	O
phrase	O
enum	B-Language
class	O
(	O
or	O
enum	B-Language
struct	B-Application
)	O
.	O
</s>
<s>
The	O
underlying	O
type	O
of	O
an	O
enumeration	B-Language
is	O
an	O
implementation-defined	O
integral	O
type	O
that	O
is	O
large	O
enough	O
to	O
hold	O
all	O
enumerated	O
values	O
;	O
it	O
does	O
not	O
have	O
to	O
be	O
the	O
smallest	O
possible	O
type	O
.	O
</s>
<s>
The	O
underlying	O
type	O
can	O
be	O
specified	O
directly	O
,	O
which	O
allows	O
"	O
forward	O
declarations	O
"	O
of	O
enumerations	B-Language
:	O
</s>
<s>
Go	B-Application
uses	O
the	O
iota	O
keyword	O
to	O
create	O
enumerated	O
constants	O
.	O
</s>
<s>
similar	O
to	O
that	O
of	O
C	B-Language
:	O
</s>
<s>
The	O
Java	B-Language
type	O
system	O
,	O
however	O
,	O
treats	O
enumerations	B-Language
as	O
a	O
type	O
separate	O
from	O
integers	O
,	O
and	O
intermixing	O
of	O
enum	B-Language
and	O
integer	O
values	O
is	O
not	O
allowed	O
.	O
</s>
<s>
In	O
fact	O
,	O
an	O
enum	B-Language
type	O
in	O
Java	B-Language
is	O
actually	O
a	O
special	O
compiler-generated	O
class	O
rather	O
than	O
an	O
arithmetic	O
type	O
,	O
and	O
enum	B-Language
values	O
behave	O
as	O
global	O
pre-generated	O
instances	O
of	O
that	O
class	O
.	O
</s>
<s>
Enum	B-Language
types	O
can	O
have	O
instance	O
methods	O
and	O
a	O
constructor	O
(	O
the	O
arguments	O
of	O
which	O
can	O
be	O
specified	O
separately	O
for	O
each	O
enum	B-Language
value	O
)	O
.	O
</s>
<s>
All	O
enum	B-Language
types	O
implicitly	O
extend	O
the	O
abstract	O
class	O
.	O
</s>
<s>
An	O
enum	B-Language
type	O
cannot	O
be	O
instantiated	O
directly	O
.	O
</s>
<s>
Internally	O
,	O
each	O
enum	B-Language
value	O
contains	O
an	O
integer	O
,	O
corresponding	O
to	O
the	O
order	O
in	O
which	O
they	O
are	O
declared	O
in	O
the	O
source	O
code	O
,	O
starting	O
from	O
0	O
.	O
</s>
<s>
The	O
programmer	O
cannot	O
set	O
a	O
custom	O
integer	O
for	O
an	O
enum	B-Language
value	O
directly	O
,	O
but	O
one	O
can	O
define	O
overloaded	B-Language
constructors	I-Language
that	O
can	O
then	O
assign	O
arbitrary	O
values	O
to	O
self-defined	O
members	O
of	O
the	O
enum	B-Language
class	O
.	O
</s>
<s>
The	O
internal	O
integer	O
can	O
be	O
obtained	O
from	O
an	O
enum	B-Language
value	O
using	O
the	O
method	O
,	O
and	O
the	O
list	O
of	O
enum	B-Language
values	O
of	O
an	O
enumeration	B-Language
type	O
can	O
be	O
obtained	O
in	O
order	O
using	O
the	O
values( )	O
method	O
.	O
</s>
<s>
It	O
is	O
generally	O
discouraged	O
for	O
programmers	O
to	O
convert	O
enums	B-Language
to	O
integers	O
and	O
vice	O
versa	O
.	O
</s>
<s>
Enumerated	B-Language
types	I-Language
are	O
Comparable	O
,	O
using	O
the	O
internal	O
integer	O
;	O
as	O
a	O
result	O
,	O
they	O
can	O
be	O
sorted	O
.	O
</s>
<s>
The	O
Java	B-Language
standard	O
library	O
provides	O
utility	O
classes	O
to	O
use	O
with	O
enumerations	B-Language
.	O
</s>
<s>
The	O
class	O
implements	O
a	O
Set	O
of	O
enum	B-Language
values	O
;	O
it	O
is	O
implemented	O
as	O
a	O
bit	B-Data_Structure
array	I-Data_Structure
,	O
which	O
makes	O
it	O
very	O
compact	O
and	O
as	O
efficient	O
as	O
explicit	O
bit	O
manipulation	O
,	O
but	O
safer	O
.	O
</s>
<s>
The	O
class	O
implements	O
a	O
Map	O
of	O
enum	B-Language
values	O
to	O
object	O
.	O
</s>
<s>
It	O
is	O
implemented	O
as	O
an	O
array	O
,	O
with	O
the	O
integer	O
value	O
of	O
the	O
enum	B-Language
value	O
serving	O
as	O
the	O
index	O
.	O
</s>
<s>
Dynamically	O
typed	O
languages	O
in	O
the	O
syntactic	O
tradition	O
of	O
C	B-Language
(	O
e.g.	O
,	O
Perl	B-Language
or	O
JavaScript	B-Language
)	O
do	O
not	O
,	O
in	O
general	O
,	O
provide	O
enumerations	B-Language
.	O
</s>
<s>
But	O
in	O
Perl	B-Language
programming	I-Language
the	O
same	O
result	O
can	O
be	O
obtained	O
with	O
the	O
shorthand	O
strings	B-Language
list	O
and	O
hashes	B-Algorithm
(	O
possibly	O
slices	O
)	O
:	O
</s>
<s>
Raku	B-Application
(	O
formerly	O
known	O
as	O
Perl	B-Application
6	I-Application
)	O
supports	O
enumerations	B-Language
.	O
</s>
<s>
There	O
are	O
multiple	O
ways	O
to	O
declare	O
enumerations	B-Language
in	O
Raku	B-Application
,	O
all	O
creating	O
a	O
back-end	O
Map	O
.	O
</s>
<s>
Enums	B-Language
were	O
added	O
in	O
PHP	O
version	O
8.1	O
.	O
</s>
<s>
The	O
Enum	B-Language
's	O
interface	O
exposes	O
a	O
method	O
that	O
gives	O
a	O
collection	O
of	O
its	O
enumerators	O
and	O
their	O
names	O
.	O
</s>
<s>
String/integer	O
-backed	O
Enums	B-Language
also	O
expose	O
the	O
backing	O
value	O
and	O
methods	O
to	O
(	O
attempt	O
)	O
deserialization	O
.	O
</s>
<s>
Though	O
Rust	O
uses	O
the	O
enum	B-Language
keyword	O
like	O
C	B-Language
,	O
it	O
uses	O
it	O
to	O
describe	O
tagged	B-Language
unions	I-Language
,	O
which	O
enums	B-Language
can	O
be	O
considered	O
a	O
degenerate	O
form	O
of	O
.	O
</s>
<s>
Rust	O
's	O
enums	B-Language
are	O
therefore	O
much	O
more	O
flexible	O
and	O
can	O
contain	O
struct	B-Application
and	O
tuple	O
variants	O
.	O
</s>
<s>
In	O
C	B-Language
,	O
enumerations	B-Language
assign	O
related	O
names	O
to	O
a	O
set	O
of	O
integer	O
values	O
.	O
</s>
<s>
In	O
Swift	B-Application
,	O
enumerations	B-Language
are	O
much	O
more	O
flexible	O
and	O
need	O
not	O
provide	O
a	O
value	O
for	O
each	O
case	O
of	O
the	O
enumeration	B-Language
.	O
</s>
<s>
If	O
a	O
value	O
(	O
termed	O
a	O
raw	O
value	O
)	O
is	O
provided	O
for	O
each	O
enumeration	B-Language
case	O
,	O
the	O
value	O
can	O
be	O
a	O
string	O
,	O
a	O
character	O
,	O
or	O
a	O
value	O
of	O
any	O
integer	O
or	O
floating-point	O
type	O
.	O
</s>
<s>
Alternatively	O
,	O
enumeration	B-Language
cases	O
can	O
specify	O
associated	O
values	O
of	O
any	O
type	O
to	O
be	O
stored	O
along	O
with	O
each	O
different	O
case	O
value	O
,	O
much	O
as	O
unions	O
or	O
variants	O
do	O
in	O
other	O
languages	O
.	O
</s>
<s>
One	O
can	O
define	O
a	O
common	O
set	O
of	O
related	O
cases	O
as	O
part	O
of	O
one	O
enumeration	B-Language
,	O
each	O
of	O
which	O
has	O
a	O
different	O
set	O
of	O
values	O
of	O
appropriate	O
types	O
associated	O
with	O
it	O
.	O
</s>
<s>
In	O
Swift	B-Application
,	O
enumerations	B-Language
are	O
a	O
first-class	O
type	O
.	O
</s>
<s>
They	O
adopt	O
many	O
features	O
traditionally	O
supported	O
only	O
by	O
classes	O
,	O
such	O
as	O
computed	O
properties	O
to	O
provide	O
additional	O
information	O
about	O
the	O
enumeration	B-Language
's	O
current	O
value	O
,	O
and	O
instance	O
methods	O
to	O
provide	O
functionality	O
related	O
to	O
the	O
values	O
the	O
enumeration	B-Language
represents	O
.	O
</s>
<s>
Enumerations	B-Language
can	O
also	O
define	O
initializers	O
to	O
provide	O
an	O
initial	O
case	O
value	O
and	O
can	O
be	O
extended	O
to	O
expand	O
their	O
functionality	O
beyond	O
their	O
original	O
implementation	O
;	O
and	O
can	O
conform	O
to	O
protocols	O
to	O
provide	O
standard	O
functionality	O
.	O
</s>
<s>
Unlike	O
C	B-Language
and	O
Objective-C	B-Language
,	O
Swift	B-Application
enumeration	B-Language
cases	O
are	O
not	O
assigned	O
a	O
default	O
integer	O
value	O
when	O
they	O
are	O
created	O
.	O
</s>
<s>
Instead	O
,	O
the	O
different	O
enumeration	B-Language
cases	O
are	O
fully-fledged	O
values	O
in	O
their	O
own	O
right	O
,	O
with	O
an	O
explicitly-defined	O
type	O
of	O
CardSuit	O
.	O
</s>
<s>
When	O
working	O
with	O
enumerations	B-Language
that	O
store	O
integer	O
or	O
string	O
raw	O
values	O
,	O
one	O
does	O
n't	O
need	O
to	O
explicitly	O
assign	O
a	O
raw	O
value	O
for	O
each	O
case	O
because	O
Swift	B-Application
will	O
automatically	O
assign	O
the	O
values	O
.	O
</s>
<s>
TypeScript	O
adds	O
an	O
'	O
enum	B-Language
 '	O
data	O
type	O
to	O
JavaScript	B-Language
.	O
</s>
<s>
By	O
default	O
,	O
enums	B-Language
number	O
members	O
starting	O
at	O
0	O
;	O
this	O
can	O
be	O
overridden	O
by	O
setting	O
the	O
value	O
of	O
the	O
first	O
:	O
</s>
<s>
There	O
is	O
also	O
a	O
for	O
creating	O
enumerations	B-Language
with	O
automatically	O
generated	O
indices	O
(	O
starting	O
with	O
one	O
)	O
:	O
</s>
<s>
Python	O
enumerations	B-Language
do	O
not	O
enforce	O
semantic	O
correctness	O
(	O
a	O
meaningless	O
comparison	O
to	O
an	O
incompatible	O
enumeration	B-Language
always	O
returns	O
False	O
rather	O
than	O
raising	O
a	O
TypeError	O
)	O
:	O
</s>
<s>
Fortran	B-Application
only	O
has	O
enumerated	B-Language
types	I-Language
for	O
interoperability	O
with	O
C	B-Language
;	O
hence	O
,	O
the	O
semantics	O
is	O
similar	O
to	O
C	B-Language
and	O
,	O
as	O
in	O
C	B-Language
,	O
the	O
enum	B-Language
values	O
are	O
just	O
integers	O
and	O
no	O
further	O
type	O
check	O
is	O
done	O
.	O
</s>
<s>
Enumerated	O
datatypes	O
in	O
Visual	B-Language
Basic	I-Language
(	O
up	O
to	O
version	O
6	O
)	O
and	O
VBA	B-Language
are	O
automatically	O
assigned	O
the	O
"	O
Long	O
"	O
datatype	O
and	O
also	O
become	O
a	O
datatype	O
themselves	O
:	O
</s>
<s>
Common	B-Language
Lisp	I-Language
uses	O
the	O
member	O
type	O
specifier	O
,	O
e.g.	O
,	O
</s>
<s>
The	O
member	O
type	O
specifier	O
is	O
not	O
valid	O
as	O
a	O
Common	B-Application
Lisp	I-Application
Object	I-Application
System	I-Application
(	O
CLOS	B-Application
)	O
parameter	O
specializer	O
,	O
however	O
.	O
</s>
<s>
Instead	O
,	O
(	O
eql	O
atom	O
)	O
,	O
which	O
is	O
the	O
equivalent	O
to	O
(	O
member	O
atom	O
)	O
may	O
be	O
used	O
(	O
that	O
is	O
,	O
only	O
one	O
member	O
of	O
the	O
set	O
may	O
be	O
specified	O
with	O
an	O
eql	O
type	O
specifier	O
,	O
however	O
,	O
it	O
may	O
be	O
used	O
as	O
a	O
CLOS	B-Application
parameter	O
specializer	O
.	O
)	O
</s>
<s>
In	O
other	O
words	O
,	O
to	O
define	O
methods	O
to	O
cover	O
an	O
enumerated	B-Language
type	I-Language
,	O
a	O
method	O
must	O
be	O
defined	O
for	O
each	O
specific	O
element	O
of	O
that	O
type	O
.	O
</s>
<s>
may	O
be	O
used	O
to	O
define	O
arbitrary	O
enumerated	B-Language
types	I-Language
at	O
runtime	O
.	O
</s>
<s>
Dart	B-Language
has	O
a	O
support	O
for	O
the	O
most	O
basic	O
form	O
of	O
enums	B-Language
and	O
has	O
a	O
syntax	O
that	O
is	O
a	O
lot	O
similar	O
with	O
other	O
languages	O
supporting	O
enums	B-Language
.	O
</s>
<s>
In	O
functional	B-Language
programming	I-Language
languages	I-Language
in	O
the	O
ML	B-Language
lineage	O
(	O
e.g.	O
,	O
Standard	B-Language
ML	I-Language
(	O
SML	B-Language
)	O
,	O
OCaml	B-Language
,	O
and	O
Haskell	B-Language
)	O
,	O
an	O
algebraic	O
data	O
type	O
with	O
only	O
nullary	B-Language
constructors	I-Language
can	O
be	O
used	O
to	O
implement	O
an	O
enumerated	B-Language
type	I-Language
.	O
</s>
<s>
For	O
example	O
(	O
in	O
the	O
syntax	O
of	O
SML	B-Language
signatures	O
)	O
:	O
</s>
<s>
However	O
,	O
Haskell	B-Language
has	O
the	O
Enum	B-Language
type	O
class	O
which	O
a	O
type	O
can	O
derive	O
or	O
implement	O
to	O
get	O
a	O
mapping	O
between	O
the	O
type	O
and	O
Int	O
.	O
</s>
<s>
Some	O
databases	O
support	O
enumerated	B-Language
types	I-Language
directly	O
.	O
</s>
<s>
MySQL	B-Application
provides	O
an	O
enumerated	B-Language
type	I-Language
ENUM	B-Language
with	O
allowable	O
values	O
specified	O
as	O
strings	B-Language
when	O
a	O
table	O
is	O
created	O
.	O
</s>
<s>
XML	O
Schema	O
supports	O
enumerated	B-Language
types	I-Language
through	O
the	O
enumeration	B-Language
facet	O
used	O
for	O
constraining	O
most	O
primitive	O
datatypes	O
such	O
as	O
strings	B-Language
.	O
</s>
