Keywords

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

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.

Contribute

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

Keyword List

• C (ANSI) (32 keywords)
• C (C18) (44 keywords)
• C# (5.0) (77 keywords)
• C++ (C++17) (73 keywords)
• Dart (1) (33 keywords)
• Elixir (1.7) (15 keywords)
• Erlang (21.2) (27 keywords)
• Go (1.11) (25 keywords)
• JS (ES2018) (34 keywords)
• Java (SE 11) (51 keywords)
• Kotlin (1.3) (30 keywords)
• PHP (7.0) (67 keywords)
• Python (2.7) (31 keywords)
• Python (3.7) (35 keywords)
• R (3.5) (20 keywords)
• Ruby (2.5) (41 keywords)
• Rust (1.31) (53 keywords)
• Scala (2.12) (40 keywords)
• Swift (4.2) (70 keywords)

C (ANSI) (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 (C18) (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:

http://www.open-std.org/jtc1/sc22/wg14/www/abq/c17_updated_proposed_fdis.pdf

C# (5.0) (77 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

Sources:

https://download.microsoft.com/download/0/B/D/0BDA894F-2CCD-4C2C-B5A7-4EB1171962E5/CSharp%20Language%20Specification.docx

C++ (C++17) (73 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

Sources:

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

Dart (1) (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:

http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-408.pdf

Elixir (1.7) (15 keywords)

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

Sources:

https://github.com/elixir-lang/elixir/blob/master/lib/elixir/pages/Syntax%20Reference.md

Erlang (21.2) (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

Go (1.11) (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

JS (ES2018) (34 keywords)

await	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

Sources:

https://www.ecma-international.org/ecma-262/9.0/index.html#sec-keywords

Java (SE 11) (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

Kotlin (1.3) (30 keywords)

as	as?	break	class
continue	do	else	false
for	fun	if	in
	interface	is
null	object	package	return
super	this	throw	true
try	typealias	val	var
when	while

Sources:

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

PHP (7.0) (67 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
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

Sources:

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

Python (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/reference/lexical_analysis.html#keywords

Python (3.7) (35 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

Sources:

https://docs.python.org/3.7/reference/lexical_analysis.html#keywords

R (3.5) (20 keywords)

...	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 (2.5) (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/2.5.0/keywords_rdoc.html

Rust (1.31) (53 keywords)

_	abstract	alignof	as
become	box	break	const
continue	crate	do	else
enum	extern	false	final
fn	for	if	impl
in	let	loop	macro
match	mod	move	mut
offsetof	override	priv	proc
pub	pure	ref	return
Self	self	sizeof	static
struct	super	trait	true
type	typeof	unsafe	unsized
use	virtual	where	while
yield

Sources:

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

Scala (2.12) (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/2.12/01-lexical-syntax.html

Swift (4.2) (70 keywords)

associatedtype	class	deinit	enum
extension	fileprivate	func	import
init	inout	internal	let
open	operator	private	protocol
public	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	rethrows	super	self
Self	throw	throws	true
try	_	#available	#colorLiteral
#column	#else	#elseif	#endif
#error	#file	#fileLiteral	#function
#if	#imageLiteral	#line	#selector
#sourceLocation	#warning

Sources:

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