Keywords

A list and count of keywords in programming languages. Based on work originally compiled by @leighmcculloch and contributors.

2022 update (WIP): I took the latest versions of several popularity lists and am ensuring the top 10 in all three lists were on this list. There have been some pretty significant changes in the past couple of years, including the addition of some soft or contextual keywords in Python 3 and Java, increasing their keyword counts significantly.

In addition to the above, I migrated CI to GitHub Actions and am worknig to ensure multiple language versions with different keyword sets are represented.

Why does it matter?

The number of keywords in a programming language can be an indication to it's simplicity/complexity, and that can impact the simplicity/complexity of the solutions that developers produce using it. Complex solutions can be more expensive to maintain and difficult to hire for. However, this is dependent on many factors and keyword count is only one; language idioms also play a massive part.

License

Source code in this repository is licensed under the MIT License.

Compiled data in this repository is licensed under the Creative Commons Attribution 4.0 International Public License.

SPDX-License-Identifier: MIT AND CC-BY-4.0

Contribute

Don't see a language here? Please open a pull request adding it!

Keyword List

• C (ANSI (C89)) (32 keywords)
• C (C11) (44 keywords)
• C (C17) (44 keywords)
• C (C99) (37 keywords)
• C# (8.0) (107 keywords)
• C++ (C++03) (74 keywords)
• C++ (C++11) (84 keywords)
• C++ (C++14) (84 keywords)
• C++ (C++17) (84 keywords)
• C++ (C++20) (92 keywords)
• C++ (C++98) (74 keywords)
• Dart (2.2) (33 keywords)
• Elixir (1.10) (15 keywords)
• Erlang (23) (27 keywords)
• Fortran (Fortran 2008) (103 keywords)
• Go (1.18) (25 keywords)
• Java (SE 11 LTS) (51 keywords)
• Java (SE 17 LTS) (67 keywords)
• JavaScript (1st edition) (35 keywords)
• JavaScript (2nd edition) (59 keywords)
• JavaScript (3rd edition) (59 keywords)
• JavaScript (5th edition) (45 keywords)
• JavaScript (6th edition) (46 keywords)
• Kotlin (1.4) (79 keywords)
• Lua (5.3) (22 keywords)
• MATLAB (R2020a) (20 keywords)
• Objective-C (2.0) (85 keywords)
• PHP (7.4) (69 keywords)
• Python 2 (2.7) (31 keywords)
• Python 3 (3.10) (38 keywords)
• R (4.0) (21 keywords)
• Ruby (2.7) (41 keywords)
• Rust (1.46) (53 keywords)
• Scala (2.13) (40 keywords)
• Swift (5.3) (97 keywords)
• Visual Basic (2019) (217 keywords)

C (ANSI (C89)) (32 keywords)

auto	break	case	char
const	continue	default	do
double	else	enum	extern
float	for	goto	if
int	long	register	return
short	signed	sizeof	static
struct	switch	typedef	union
unsigned	void	volatile	while

Sources:

http://port70.net/~nsz/c/c89/c89-draft.html#3.1.1

C (C11) (44 keywords)

auto	break	case	char
const	continue	default	do
double	else	enum	extern
float	for	goto	if
inline	int	long	register
restrict	return	short	signed
sizeof	static	struct	switch
typedef	union	unsigned	void
volatile	while	_Alignas	_Alignof
_Atomic	_Bool	_Complex	_Generic
_Imaginary	_Noreturn	_Static_assert	_Thread_local

Sources:

https://www.open-std.org/JTC1/SC22/WG14/www/docs/n1570.pdf

C (C17) (44 keywords)

auto	break	case	char
const	continue	default	do
double	else	enum	extern
float	for	goto	if
inline	int	long	register
restrict	return	short	signed
sizeof	static	struct	switch
typedef	union	unsigned	void
volatile	while	_Alignas	_Alignof
_Atomic	_Bool	_Complex	_Generic
_Imaginary	_Noreturn	_Static_assert	_Thread_local

Sources:

https://www.open-std.org/JTC1/SC22/WG14/www/docs/n2310.pdf

C (C99) (37 keywords)

auto	break	case	char
const	continue	default	do
double	else	enum	extern
float	for	goto	if
inline	int	long	register
restrict	return	short	signed
sizeof	static	struct	switch
typedef	union	unsigned	void
volatile	while	_Bool	_Complex
_Imaginary

Sources:

https://www.open-std.org/JTC1/SC22/WG14/www/docs/n1256.pdf

C# (8.0) (107 keywords)

abstract	as	base	bool
break	byte	case	catch
char	checked	class	const
continue	decimal	default	delegate
do	double	else	enum
event	explicit	extern	false
finally	fixed	float	for
foreach	goto	if	implicit
in	int	interface	internal
is	lock	long	namespace
new	null	object	operator
out	override	params	private
protected	public	readonly	ref
return	sbyte	sealed	short
sizeof	stackalloc	static	string
struct	switch	this	throw
true	try	typeof	uint
ulong	unchecked	unsafe	ushort
using	virtual	void	volatile
while	add	alias	ascending
async	await	by	descending
dynamic	equals	from	get
global	group	into	join
let	nameof	notnull	on
orderby	partial	remove	select
set	unmanaged	value	var
when	where	yield

Sources:

https://standards.iso.org/ittf/PubliclyAvailableStandards/c075178_ISO_IEC_23270_2018.zip

C++ (C++03) (74 keywords)

asm	auto	bool	break
case	catch	char	class
const	const_cast	continue	default
delete	do	double	dynamic_cast
else	enum	explicit	export
extern	false	float	for
friend	goto	if	inline
int	long	mutable	namespace
new	operator	private	protected
public	register	reinterpret_cast	return
short	signed	sizeof	static
static_cast	struct	switch	template
this	throw	true	try
typedef	typeid	typename	union
unsigned	using	virtual	void
volatile	wchar_t	while	and
and_eq	bitand	bitor	compl
not	not_eq	or	or_eq
xor	xor_eq

Sources:

http://staff.ustc.edu.cn/~zhuang/cpp/specs/ISO_IEC%2014882%202003.pdf

C++ (C++11) (84 keywords)

alignas	alignof	asm	auto
bool	break	case	catch
char	char_16t	char_32t	class
const	constexpr	const_cast	continue
decltype	default	delete	do
double	dynamic_cast	else	enum
explicit	export	extern	false
float	for	friend	goto
if	inline	int	long
mutable	namespace	new	noexcept
nullptr	operator	private	protected
public	register	reinterpret_cast	return
short	signed	sizeof	static
static_assert	static_cast	struct	switch
template	this	thread_local	throw
true	try	typedef	typeid
typename	union	unsigned	using
virtual	void	volatile	wchar_t
while	and	and_eq	bitand
bitor	compl	not	not_eq
or	or_eq	xor	xor_eq

Sources:

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf

C++ (C++14) (84 keywords)

alignas	alignof	asm	auto
bool	break	case	catch
char	char_16t	char_32t	class
const	constexpr	const_cast	continue
decltype	default	delete	do
double	dynamic_cast	else	enum
explicit	export	extern	false
float	for	friend	goto
if	inline	int	long
mutable	namespace	new	noexcept
nullptr	operator	private	protected
public	register	reinterpret_cast	return
short	signed	sizeof	static
static_assert	static_cast	struct	switch
template	this	thread_local	throw
true	try	typedef	typeid
typename	union	unsigned	using
virtual	void	volatile	wchar_t
while	and	and_eq	bitand
bitor	compl	not	not_eq
or	or_eq	xor	xor_eq

Sources:

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf

C++ (C++17) (84 keywords)

alignas	alignof	asm	auto
bool	break	case	catch
char	char16_t	char32_t	class
const	constexpr	const_cast	continue
decltype	default	delete	do
double	dynamic_cast	else	enum
explicit	export	extern	false
float	for	friend	goto
if	inline	int	long
mutable	namespace	new	noexcept
nullptr	operator	private	protected
public	register	reinterpret_cast	return
short	signed	sizeof	static
static_assert	static_cast	struct	switch
template	this	thread_local	throw
true	try	typedef	typeid
typename	union	unsigned	using
virtual	void	volatile	wchar_t
while	and	and_eq	bitand
bitor	compl	not	not_eq
or	or_eq	xor	xor_eq

Sources:

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/n4659.pdf

C++ (C++20) (92 keywords)

alignas	alignof	asm	auto
bool	break	case	catch
char	char8_t	char16_t	char32_t
class	concept	const	consteval
constexpr	constinit	const_cast	continue
co_await	co_return	co_yield	decltype
default	delete	do	double
dynamic_cast	else	enum	explicit
export	extern	false	float
for	friend	goto	if
inline	int	long	mutable
namespace	new	noexcept	nullptr
operator	private	protected	public
register	reinterpret_cast	requires	return
short	signed	sizeof	static
static_assert	static_cast	struct	switch
template	this	thread_local	throw
true	try	typedef	typeid
typename	union	unsigned	using
virtual	void	volatile	wchar_t
while	and	and_eq	bitand
bitor	compl	not	not_eq
or	or_eq	xor	xor_eq

Sources:

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/n4849.pdf

C++ (C++98) (74 keywords)

asm	auto	bool	break
case	catch	char	class
const	const_cast	continue	default
delete	do	double	dynamic_cast
else	enum	explicit	export
extern	false	float	for
friend	goto	if	inline
int	long	mutable	namespace
new	operator	private	protected
public	register	reinterpret_cast	return
short	signed	sizeof	static
static_cast	struct	switch	template
this	throw	true	try
typedef	typeid	typename	union
unsigned	using	virtual	void
volatile	wchar_t	while	and
and_eq	bitand	bitor	compl
not	not_eq	or	or_eq
xor	xor_eq

Sources:

https://www.lirmm.fr/~ducour/Doc-objets/ISO+IEC+14882-1998.pdf

Dart (2.2) (33 keywords)

assert	break	case	catch
class	const	continue	default
do	else	enum	extends
false	final	finally	for
if	in	is	new
null	rethrow	return	super
switch	this	throw	true
try	var	void	while
with

Sources:

https://dart.dev/guides/language/specifications/DartLangSpec-v2.2.pdf

Elixir (1.10) (15 keywords)

true	false	nil	when
and	or	not	in
fn	do	end	catch
rescue	after	else

Sources:

https://hexdocs.pm/elixir/syntax-reference.html#reserved-words

Erlang (23) (27 keywords)

after	and	andalso	band
begin	bnot	bor	bsl
bsr	bxor	case	catch
cond	div	end	fun
if	let	not	of
or	orelse	receive	rem
try	when	xor

Sources:

http://erlang.org/doc/reference_manual/introduction.html#reserved-words

Fortran (Fortran 2008) (103 keywords)

abstract	allocatable	allocate	assign
associate	asynchronous	backspace	bind
block	block data	call	case
class	close	codimension	common
contains	contiguous	continue	critical
cycle	data	deallocate	deferred
dimension	do	do concurrent	elemental
else	else if	elsewhere	end
endfile	endif	entry	enum
enumerator	equivalence	error stop	exit
extends	external	final	flush
forall	format	function	generic
goto	if	implicit	import
include	inquire	intent	interface
intrinsic	lock	module	namelist
non_overridable	nopass	nullify	only
open	operator	optional	parameter
pass	pause	pointer	print
private	procedure	program	protected
public	pure	read	recursive
result	return	rewind	rewrite
save	select	sequence	stop
submodule	subroutine	sync all	sync images
sync memory	target	then	unlock
use	value	volatile	wait
where	while	write

Sources:

http://fortranwiki.org/fortran/show/Keywords

Go (1.18) (25 keywords)

break	case	chan	const
continue	default	defer	else
fallthrough	for	func	go
goto	if	import	interface
map	package	range	return
select	struct	switch	type
var

Sources:

https://golang.org/ref/spec#Keywords

Java (SE 11 LTS) (51 keywords)

abstract	assert	boolean	break
byte	case	catch	char
class	const	continue	default
do	double	else	enum
extends	final	finally	float
for	if	goto	implements
import	instanceof	int	interface
long	native	new	package
private	protected	public	return
short	static	strictfp	super
switch	synchronized	this	throw
throws	transient	try	void
volatile	while	_

Sources:

https://docs.oracle.com/javase/specs/jls/se11/html/jls-3.html#jls-3.9

Java (SE 17 LTS) (67 keywords)

abstract	assert	boolean	break
byte	case	catch	char
class	const	continue	default
do	double	else	enum
extends	final	finally	float
for	if	goto	implements
import	instanceof	int	interface
long	native	new	package
private	protected	public	return
short	static	strictfp	super
switch	synchronized	this	throw
throws	transient	try	void
volatile	while	_	exports
module	non-sealed	open	opens
permits	provides	record	requires
sealed	to	transitive	uses
var	with	yield

Sources:

https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.9

JavaScript (1st edition) (35 keywords)

break	continue	delete	else
for	function	if	in
new	return	this	typeof
var	void	while	with
case	catch	class	const
debugger	default	do	enum
export	extends	finally	import
super	switch	throw	try
null	true	false

Sources:

https://www.ecma-international.org/wp-content/uploads/ECMA-262_1st_edition_june_1997.pdf

JavaScript (2nd edition) (59 keywords)

break	continue	delete	else
for	function	if	in
new	return	this	typeof
var	void	while	with
abstract	boolean	byte	case
catch	char	class	const
debugger	default	do	double
enum	export	extends	final
finally	float	goto	implements
import	instanceof	int	interface
long	native	package	private
protected	public	short	static
super	switch	synchronized	throw
throws	transient	try	volatile
null	true	false

Sources:

https://www.ecma-international.org/wp-content/uploads/ECMA-262_2nd_edition_august_1998.pdf

JavaScript (3rd edition) (59 keywords)

break	case	catch	continue
default	delete	do	else
finally	for	function	if
in	instanceof	new	return
switch	this	throw	try
typeof	var	void	while
with	abstract	boolean	byte
char	class	const	debugger
double	enum	export	extends
final	float	goto	implements
import	int	interface	long
native	package	private	protected
public	short	static	super
synchronized	throws	transient	volatile
null	true	false

Sources:

https://www.ecma-international.org/wp-content/uploads/ECMA-262_3rd_edition_december_1999.pdf

JavaScript (5th edition) (45 keywords)

break	case	catch	continue
debugger	default	delete	do
else	finally	for	function
if	in	instanceof	new
return	switch	this	throw
try	typeof	var	void
while	with	class	const
enum	export	extends	import
super	implements	interface	let
package	private	protected	public
static	yield	null	true
false

Sources:

https://www.ecma-international.org/wp-content/uploads/ECMA-262_5th_edition_december_2009.pdf

JavaScript (6th edition) (46 keywords)

break	case	catch	class
const	continue	debugger	default
delete	do	else	export
extends	finally	for	function
if	import	in	instanceof
new	return	super	switch
this	throw	try	typeof
var	void	while	with
yield	let	static	enum
await	implements	interface	package
private	protected	public	null
true	false

Sources:

https://www.ecma-international.org/wp-content/uploads/ECMA-262_5th_edition_december_2009.pdf

Kotlin (1.4) (79 keywords)

as	as?	break	class
continue	do	else	false
for	fun	if	in
!in	interface	is	!is
null	object	package	return
super	this	throw	true
try	typealias	typeof	val
var	when	while	by
catch	constructor	delegate	dynamic
field	file	finally	get
import	init	param	property
receiver	set	setparam	where
actual	abstract	annotation	companion
const	crossinline	data	enum
expect	external	final	infix
inline	inner	internal	lateinit
noinline	open	operator	out
override	private	protected	public
reified	sealed	suspend	tailrec
vararg	field	it

Sources:

https://kotlinlang.org/docs/reference/keyword-reference.html

Lua (5.3) (22 keywords)

and	break	do	else
elseif	end	false	for
function	goto	if	in
local	nil	not	or
repeat	return	then	true
until	while

Sources:

https://www.lua.org/manual/5.3/manual.html#3.1

MATLAB (R2020a) (20 keywords)

break	case	catch	classdef
continue	else	elseif	end
for	function	global	if
otherwise	parfor	persistent	return
spmd	switch	try	while

Sources:

https://www.mathworks.com/help/matlab/ref/iskeyword.html

Objective-C (2.0) (85 keywords)

asm	auto	break	case
char	const	continue	default
do	double	else	enum
extern	float	for	goto
if	inline	int	long
register	restrict	return	short
signed	sizeof	static	struct
switch	typedef	union	unsigned
void	volatile	while	_Bool
_Complex	__block	Imaginary	id
Class	SEL	IMP	BOOL
nil	Nil	YES	NO
self	super	_cmd	__strong
__weak	__autoreleasing	__unsafe_unretained	oneway
In	out	inout	bycopy
byref	@autoreleasepool	@interface	@implementation
@protocol	@end	@private	@protected
@public	@package	@try	@throw
@catch()	@finally	@property	@synthesize
@dynamic	@class	@selector()	@protocol()
@required	@optional	@encode	@"string"
@synchronized()

Sources:

https://learning.oreilly.com/library/view/learning-objective-c-20/9780321712110/

PHP (7.4) (69 keywords)

__halt_compiler()	abstract	and	array()
as	break	callable	case
catch	class	clone	const
continue	declare	default	die()
do	echo	else	elseif
empty()	enddeclare	endfor	endforeach
endif	endswitch	endwhile	eval()
exit()	extends	final	finally
fn	for	foreach	function
global	goto	if	implements
include	include_once	instanceof	insteadof
interface	isset()	list()	namespace
new	or	print	private
protected	public	require	require_once
return	static	switch	throw
trait	try	unset()	use
var	while	xor	yield
yield from

Sources:

http://php.net/manual/en/reserved.keywords.php

Python 2 (2.7) (31 keywords)

and	as	assert	break
class	continue	def	del
elif	else	except	exec
finally	for	from	global
if	import	in	is
lambda	not	or	pass
print	raise	return	try
while	with	yield

Sources:

https://docs.python.org/2.7/reference/lexical_analysis.html#keywords

Python 3 (3.10) (38 keywords)

False	None	True	and
as	assert	async	await
break	class	continue	def
del	elif	else	except
finally	for	from	global
if	import	in	is
lambda	nonlocal	not	or
pass	raise	return	try
while	with	yield	match
case	_

Sources:

https://docs.python.org/3.10/reference/lexical_analysis.html#keywords https://docs.python.org/3.10/reference/lexical_analysis.html#keywords

R (4.0) (21 keywords)

...	..1	FALSE	Inf
NA	NA_character_	NA_complex_	NA_integer_
NA_real_	NaN	NULL	TRUE
break	else	for	function
if	in	next	repeat
while

Sources:

https://cran.r-project.org/doc/manuals/r-release/R-lang.html#Reserved-words

Ruby (2.7) (41 keywords)

ENCODING	LINE	FILE	BEGIN
END	alias	and	begin
break	case	class	def
defined?	do	else	elsif
end	ensure	false	for
if	in	module	next
nil	not	or	redo
rescue	retry	return	self
super	then	true	undef
unless	until	when	while
yield

Sources:

https://docs.ruby-lang.org/en/2.7.0/keywords_rdoc.html

Rust (1.46) (53 keywords)

as	break	const	continue
crate	else	enum	extern
false	fn	for	if
impl	in	let	loop
match	mod	move	mut
pub	ref	return	self
Self	static	struct	super
trait	true	type	unsafe
use	where	while	async
await	dyn	abstract	become
box	do	final	macro
override	priv	typeof	unsized
virtual	yield	try	union
'static

Sources:

https://doc.rust-lang.org/grammar.html#keywords

Scala (2.13) (40 keywords)

abstract	case	catch	class
def	do	else	extends
false	final	finally	for
forSome	if	implicit	import
lazy	macro	match	new
null	object	override	package
private	protected	return	sealed
super	this	throw	trait
try	true	type	val
var	while	with	yield

Sources:

https://scala-lang.org/files/archive/spec/2.13/01-lexical-syntax.html

Swift (5.3) (97 keywords)

associatedtype	class	deinit	enum
extension	fileprivate	func	import
init	inout	internal	let
open	operator	private	protocol
public	rethrows	static	struct
subscript	typealias	var	break
case	continue	default	defer
do	else	fallthrough	for
guard	if	in	repeat
return	switch	where	while
as	Any	catch	false
is	nil	super	self
Self	throw	throws	true
try	_	#available	#colorLiteral
#column	#else	#elseif	#endif
#error	#file	#filePath	#fileLiteral
#function	#if	#imageLiteral	#line
#selector	#sourceLocation	#warning	associativity
convenience	dynamic	didSet	final
get	infix	indirect	lazy
left	mutating	none	nonmutating
optional	override	postfix	precedence
prefix	Protocol	required	right
set	Type	unowned	weak
willSet

Sources:

https://docs.swift.org/swift-book/ReferenceManual/LexicalStructure.html

Visual Basic (2019) (217 keywords)

AddHandler	AddressOf	Alias	And
AndAlso	As	Boolean	ByRef
Byte	ByVal	Call	Case
Catch	CBool	CByte	CChar
CDate	CDbl	CDec	Char
CInt	Class	CLng	CObj
Const	Continue	CSByte	CShort
CSng	CStr	CType	CUInt
CULng	CUShort	Date	Decimal
Declare	Default	Delegate	Dim
DirectCast	Do	Double	Each
Else	ElseIf	End	EndIf
Enum	Erase	Error	Event
Exit	False	Finally	For
For Each	Friend	Function	Get
GetType	GetXMLNamespace	Global	GoSub
GoTo	Handles	If	If()
Implements	Imports	In	Inherits
Integer	Interface	Is	IsNot
Let	Lib	Like	Long
Loop	Me	Mod	Module
MustInherit	MustOverride	MyBase	MyClass
NameOf	Namespace	Narrowing	New
Next	Not	Nothnig	NotInheritable
NotOverridable	Object	Of	On
Operator	Option	Optional	Or
OrElse	Out	Overloads	Overridable
Overrides	ParamArray	Partial	Private
Property	Protected	Public	RaiseEvent
ReadOnly	ReDim	REM	RemoveHandler
Resume	Return	SByte	Select
Set	Shadows	Shared	Short
Single	Static	Step	Stop
String	Structure	Sub	SyncLock
Then	Throw	To	True
Try	TryCast	TypeOf	UInteger
ULong	UShort	Using	Variant
Wend	When	While	Widening
With	WithEvents	WriteOnly	Xor
#Const	#Else	#ElseIf	#End
#If	=	&	&=
*	*=	/	/=
\	=	^	^=
+	+=	-	-=
>>	>>=	<<	<<=
Aggregate	Ansi	Assembly	Async
Auto	Await	Binary	Compare
Custom	Distinct	Equals	Explicit
From	Group By	Group Join	Into
IsFalse	IsTrue	Iterator	Join
Key	Mid	Off	Order By
Preserve	Skip	Skip While	Strict
Take	Take While	Text	Unicode
Until	Where	Yield	#ExternalSource
#Region

Sources:

https://docs.microsoft.com/en-us/dotnet/visual-basic/language-reference/keywords/