#Grammar
##General
The grammar notation is described in [Grammars section](09-lexical-structure.md#grammars).
##Lexical Grammar
###General
input-file::
input-element
input-file input-element
input-element::
comment
white-space
token
###Comments
comment::
single-line-comment
delimited-comment
single-line-comment::
// input-charactersopt
# input-charactersopt
input-characters::
input-character
input-characters input-character
input-character::
Any source character except new-line
new-line::
Carriage-return character (U+000D)
Line-feed character (U+000A)
Carriage-return character (U+000D) followed by line-feed character (U+000A)
delimited-comment::
/* No characters or any source character sequence except */ */
###White Space
white-space::
white-space-character
white-space white-space-character
white-space-character::
new-line
Space character (U+0020)
Horizontal-tab character (U+0009)
###Tokens
####General
token::
variable-name
name
keyword
literal
operator-or-punctuator
####Names
variable-name::
$ name
namespace-name::
name
namespace-name \ name
namespace-name-as-a-prefix::
\
\opt namespace-name \
namespace \
namespace \ namespace-name \
qualified-name::
namespace-name-as-a-prefixopt name
name::
name-nondigit
name name-nondigit
name digit
name-nondigit::
nondigit
one of the characters U+0080–U+00ff
nondigit:: one of
_
a b c d e f g h i j k l m
n o p q r s t u v w x y z
A B C D E F G H I J K L M
N O P Q R S T U V W X Y Z
###Keywords
keyword:: one of
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 yield from
###Literals
####Integer Literals
integer-literal::
decimal-literal
octal-literal
hexadecimal-literal
binary-literal
decimal-literal::
nonzero-digit
decimal-literal digit
octal-literal::
0
octal-literal octal-digit
hexadecimal-literal::
hexadecimal-prefix hexadecimal-digit
hexadecimal-literal hexadecimal-digit
hexadecimal-prefix:: one of
0x 0X
binary-literal::
binary-prefix binary-digit
binary-literal binary-digit
binary-prefix:: one of
0b 0B
digit:: one of
0 1 2 3 4 5 6 7 8 9
nonzero-digit:: one of
1 2 3 4 5 6 7 8 9
octal-digit:: one of
0 1 2 3 4 5 6 7
hexadecimal-digit:: one of
0 1 2 3 4 5 6 7 8 9
a b c d e f
A B C D E F
binary-digit:: one of
0 1
####Floating-Point Literals
floating-literal::
fractional-literal exponent-partopt
digit-sequence exponent-part
fractional-literal::
digit-sequenceopt . digit-sequence
digit-sequence .
exponent-part::
e signopt digit-sequence
E signopt digit-sequence
sign:: one of
+ -
digit-sequence::
digit
digit-sequence digit
####String Literals
string-literal::
single-quoted-string-literal
double-quoted-string-literal
heredoc-string-literal
nowdoc-string-literal
single-quoted-string-literal::
b-prefixopt ' sq-char-sequenceopt '
sq-char-sequence::
sq-char
sq-char-sequence sq-char
sq-char::
sq-escape-sequence
\opt any member of the source character set except single-quote (') or backslash (\)
sq-escape-sequence:: one of
\' \\
b-prefix:: one of
b B
double-quoted-string-literal::
b-prefixopt " dq-char-sequenceopt "
dq-char-sequence::
dq-char
dq-char-sequence dq-char
dq-char::
dq-escape-sequence
any member of the source character set except double-quote (") or backslash (\)
\ any member of the source character set except "\$efnrtvxX or octal-digit
dq-escape-sequence::
dq-simple-escape-sequence
dq-octal-escape-sequence
dq-hexadecimal-escape-sequence
dq-unicode-escape-sequence
dq-simple-escape-sequence:: one of
\" \\ \$ \e \f \n \r \t \v
dq-octal-escape-sequence::
\ octal-digit
\ octal-digit octal-digit
\ octal-digit octal-digit octal-digit
dq-hexadecimal-escape-sequence::
\x hexadecimal-digit hexadecimal-digitopt
\X hexadecimal-digit hexadecimal-digitopt
dq-unicode-escape-sequence::
\u{ codepoint-digits }
codepoint-digits::
hexadecimal-digit
hexadecimal-digit codepoint-digits
string-variable::
variable-name offset-or-propertyopt
${ expression }
offset-or-property::
offset-in-string
property-in-string
offset-in-string::
[ name ]
[ variable-name ]
[ integer-literal ]
property-in-string::
-> name
heredoc-string-literal::
b-prefixopt <<< hd-start-identifier new-line hd-bodyopt hd-end-identifier ;opt new-line
hd-start-identifier::
name
" name "
hd-end-identifier::
name
hd-body::
hd-char-sequenceopt new-line
hd-char-sequence::
hd-char
hd-char-sequence hd-char
hd-char::
hd-escape-sequence
any member of the source character set except backslash (\)
\ any member of the source character set except \$efnrtvxX or octal-digit
hd-escape-sequence::
hd-simple-escape-sequence
dq-octal-escape-sequence
dq-hexadecimal-escape-sequence
dq-unicode-escape-sequence
hd-simple-escape-sequence:: one of
\\ \$ \e \f \n \r \t \v
nowdoc-string-literal::
b-prefixopt <<< ' name ' new-line hd-bodyopt name ;opt new-line
###Operators and Punctuators
operator-or-punctuator:: one of
[ ] ( ) { } . -> ++ -- ** * + - ~ !
$ / % << >> < > <= >= == === != !== ^ |
& && || ? : ; = **= *= /= %= += -= .= <<=
>>= &= ^= |= , ?? <=> ... \
##Syntactic Grammar
###Program Structure
script:
script-section
script script-section
script-section:
textopt start-tag statement-listopt end-tagopt textopt
start-tag:
<?php
<?=
end-tag:
?>
text:
arbitrary text not containing any of start-tag sequences
###Variables
function-static-declaration:
static static-variable-name-list ;
static-variable-name-list:
static-variable-declaration
static-variable-name-list , static-variable-declaration
static-variable-declaration:
variable-name function-static-initializeropt
function-static-initializer:
= constant-expression
global-declaration:
global variable-name-list ;
variable-name-list:
expression
variable-name-list , expression
###Expressions
####Primary Expressions
primary-expression:
variable-name
qualified-name
literal
constant-expression
intrinsic
anonymous-function-creation-expression
( expression )
$this
literal:
integer-literal
floating-literal
string-literal
intrinsic:
intrisic-construct
intrisic-operator
intrisic-construct:
echo-intrinsic
list-intrinsic
unset-intrinsic
intrinsic-operator:
array-intrinsic
empty-intrinsic
eval-intrinsic
exit-intrinsic
isset-intrinsic
print-intrinsic
array-intrinsic:
array ( array-initializeropt )
echo-intrinsic:
echo expression
echo expression-list-two-or-more
expression-list-two-or-more:
expression , expression
expression-list-two-or-more , expression
empty-intrinsic:
empty ( expression )
eval-intrinsic:
eval ( expression )
exit-intrinsic:
exit expressionopt
exit ( expressionopt )
die expressionopt
die ( expressionopt )
isset-intrinsic:
isset ( expression-list-one-or-more )
expression-list-one-or-more:
expression
expression-list-one-or-more , expression
list-intrinsic:
list ( list-expression-listopt )
list-expression-list:
unkeyed-list-expression-list
keyed-list-expression-list ,opt
unkeyed-list-expression-list:
list-or-variable
,
unkeyed-list-expression-list , list-or-variableopt
keyed-list-expression-list:
expression => list-or-variable
keyed-list-expression-list , expression => list-or-variable
list-or-variable:
list-intrinsic
expression
print-intrinsic:
print expression
print ( expression )
unset-intrinsic:
unset ( expression-list-one-or-more )
anonymous-function-creation-expression:
staticopt function &opt ( parameter-declaration-listopt ) return-typeopt anonymous-function-use-clauseopt
compound-statement
anonymous-function-use-clause:
use ( use-variable-name-list )
use-variable-name-list:
&opt variable-name
use-variable-name-list , &opt variable-name
####Postfix Operators
postfix-expression:
primary-expression
clone-expression
object-creation-expression
array-creation-expression
subscript-expression
function-call-expression
member-selection-expression
postfix-increment-expression
postfix-decrement-expression
scope-resolution-expression
exponentiation-expression
clone-expression:
clone expression
object-creation-expression:
new class-type-designator ( argument-expression-listopt )
new class-type-designator
new class ( argument-expression-listopt )
class-base-clauseopt class-interface-clauseopt
{ opt }
new class class-base-clauseopt class-interface-clauseopt
{ class-member-declarationsopt }
class-type-designator:
qualified-name
expression
array-creation-expression:
array ( array-initializeropt )
[ array-initializeropt ]
array-initializer:
array-initializer-list ,opt
array-initializer-list:
array-element-initializer
array-element-initializer , array-initializer-list
array-element-initializer:
&opt element-value
element-key => &opt element-value
element-key:
expression
element-value
expression
subscript-expression:
postfix-expression [ expressionopt ]
postfix-expression { expression } [Deprecated form]
function-call-expression:
qualified-name ( argument-expression-listopt )
postfix-expression ( argument-expression-listopt )
argument-expression-list:
argument-expression
argument-expression-list , argument-expression
argument-expression:
variadic-unpacking
assignment-expression
variadic-unpacking:
... assignment-expression
member-selection-expression:
postfix-expression -> member-selection-designator
member-selection-designator:
name
expression
postfix-increment-expression:
unary-expression ++
postfix-decrement-expression:
unary-expression --
scope-resolution-expression:
scope-resolution-qualifier :: member-selection-designator
scope-resolution-qualifier :: class
scope-resolution-qualifier:
relative-scope
qualified-name
expression
relative-scope:
self
parent
static
exponentiation-expression:
expression ** expression
####Unary Operators
unary-expression:
postfix-expression
prefix-increment-expression
prefix-decrement-expression
unary-op-expression
error-control-expression
shell-command-expression
cast-expression
variable-name-creation-expression
prefix-increment-expression:
++ unary-expression
prefix-decrement-expression:
-- unary-expression
unary-op-expression:
unary-operator cast-expression
unary-operator: one of
+ - ! ~
error-control-expression:
@ expression
shell-command-expression:
` dq-char-sequenceopt `
cast-expression:
unary-expression
( cast-type ) expression
cast-type: one of
array binary bool boolean double int integer float object
real string unset
variable-name-creation-expression:
$ expression
$ { expression }
####instanceof Operator
instanceof-expression:
unary-expression
instanceof-subject instanceof instanceof-type-designator
instanceof-subject:
expression
instanceof-type-designator:
qualified-name
expression
####Multiplicative Operators
multiplicative-expression:
instanceof-expression
multiplicative-expression * instanceof-expression
multiplicative-expression / instanceof-expression
multiplicative-expression % instanceof-expression
####Additive Operators
additive-expression:
multiplicative-expression
additive-expression + multiplicative-expression
additive-expression - multiplicative-expression
additive-expression . multiplicative-expression
####Bitwise Shift Operators
shift-expression:
additive-expression
shift-expression << additive-expression
shift-expression >> additive-expression
####Relational Operators
relational-expression:
shift-expression
relational-expression < shift-expression
relational-expression > shift-expression
relational-expression <= shift-expression
relational-expression >= shift-expression
relational-expression <=> shift-expression
####Equality Operators
equality-expression:
relational-expression
equality-expression == relational-expression
equality-expression != relational-expression
equality-expression <> relational-expression
equality-expression === relational-expression
equality-expression !== relational-expression
####Bitwise Logical Operators
bitwise-AND-expression:
equality-expression
bit-wise-AND-expression & equality-expression
bitwise-exc-OR-expression:
bitwise-AND-expression
bitwise-exc-OR-expression ^ bitwise-AND-expression
bitwise-inc-OR-expression:
bitwise-exc-OR-expression
bitwise-inc-OR-expression | bitwise-exc-OR-expression
####Logical Operators (form 1)
logical-AND-expression-1:
bitwise-incl-OR-expression
logical-AND-expression-1 && bitwise-inc-OR-expression
logical-inc-OR-expression-1:
logical-AND-expression-1
logical-inc-OR-expression-1 || logical-AND-expression-1
####Conditional Operator
conditional-expression:
logical-inc-OR-expression-1
logical-inc-OR-expression-1 ? expressionopt : conditional-expression
####Coalesce Operator
coalesce-expression:
logical-inc-OR-expression ?? expression
####Assignment Operators
assignment-expression:
conditional-expression
coalesce-expression
simple-assignment-expression
byref-assignment-expression
compound-assignment-expression
simple-assignment-expression:
unary-expression = assignment-expression
byref-assignment-expression:
unary-expression = & assignment-expression
compound-assignment-expression:
unary-expression compound-assignment-operator assignment-expression
compound-assignment-operator: one of
**= *= /= %= += -= .= <<= >>= &= ^= |=
####Logical Operators (form 2)
logical-AND-expression-2:
assignment-expression
logical-AND-expression-2 and assignment-expression
logical-exc-OR-expression:
logical-AND-expression-2
logical-exc-OR-expression xor logical-AND-expression-2
logical-inc-OR-expression-2:
logical-exc-OR-expression
logical-inc-OR-expression-2 or logical-exc-OR-expression
####yield Operator
yield-expression:
logical-inc-OR-expression-2
yield array-element-initializer
####Script Inclusion Operators
expression:
yield-expression
include-expression
include-once-expression
require-expression
require-once-expression
include-expression:
include ( expression )
include expression
include-once-expression:
include_once ( expression )
include_once expression
require-expression:
require ( expression )
require expression
require-once-expression:
require_once ( expression )
require_once expression
####Constant Expressions
constant-expression:
array-creation-expression
expression
###Statements
####General
statement:
compound-statement
labeled-statement
expression-statement
selection-statement
iteration-statement
jump-statement
declare-statement
const-declaration
function-definition
class-declaration
interface-declaration
trait-declaration
namespace-definition
namespace-use-declaration
global-declaration
function-static-declaration
####Compound Statements
compound-statement:
{ statement-listopt }
statement-list:
statement
statement-list statement
####Labeled Statements
labeled-statement:
named-label-statement
case-statement
default-statement
named-label-statement:
name : statement
case-statement:
case expression case-default-label-terminator statement
default-statement:
default case-default-label-terminator statement
case-default-label-terminator:
:
;
####Expression Statements
expression-statement:
expressionopt ;
selection-statement:
if-statement
switch-statement
if-statement:
if ( expression ) statement elseif-clauses-1opt else-clause-1opt
if ( expression ) : statement-list elseif-clauses-2opt else-clause-2opt endif ;
elseif-clauses-1:
elseif-clause-1
elseif-clauses-1 elseif-clause-1
elseif-clause-1:
elseif ( expression ) statement
else-clause-1:
else statement
elseif-clauses-2:
elseif-clause-2
elseif-clauses-2 elseif-clause-2
elseif-clause-2:
elseif ( expression ) : statement-list
else-clause-2:
else : statement-list
switch-statement:
switch ( expression ) { case-statementsopt }
switch ( expression ) : case-statementsopt endswitch;
case-statements:
case-statement statement-listopt case-statementsopt
default-statement statement-listopt case-statementsopt
####Iteration Statements
iteration-statement:
while-statement
do-statement
for-statement
foreach-statement
while-statement:
while ( expression ) statement
while ( expression ) : statement-list endwhile ;
do-statement:
do statement while ( expression ) ;
for-statement:
for ( for-initializeropt ; for-controlopt ; for-end-of-loopopt ) statement
for ( for-initializeropt ; for-controlopt ; for-end-of-loopopt ) : statement-list endfor ;
for-initializer:
for-expression-group
for-control:
for-expression-group
for-end-of-loop:
for-expression-group
for-expression-group:
expression
for-expression-group , expression
foreach-statement:
foreach ( foreach-collection-name as foreach-keyopt foreach-value ) statement
foreach ( foreach-collection-name as foreach-keyopt foreach-value ) : statement-list endforeach ;
foreach-collection-name:
expression
foreach-key:
expression =>
foreach-value:
&opt expression
list-intrinsic
####Jump Statements
jump-statement:
goto-statement
continue-statement
break-statement
return-statement
throw-statement
goto-statement:
goto name ;
continue-statement:
continue breakout-levelopt ;
breakout-level:
integer-literal
break-statement:
break breakout-levelopt ;
return-statement:
return expressionopt ;
throw-statement:
throw expression ;
####The try Statement
try-statement:
try compound-statement catch-clauses
try compound-statement finally-clause
try compound-statement catch-clauses finally-clause
catch-clauses:
catch-clause
catch-clauses catch-clause
catch-clause:
catch ( qualified-name variable-name ) compound-statement
finally-clause:
finally compound-statement
####The declare Statement
declare-statement:
declare ( declare-directive ) statement
declare ( declare-directive ) : statement-list enddeclare ;
declare ( declare-directive ) ;
declare-directive:
ticks = literal
encoding = literal
strict_types = literal
###Functions
function-definition:
function-definition-header compound-statement
function-definition-header:
function &opt name ( parameter-declaration-listopt ) return-typeopt
parameter-declaration-list:
simple-parameter-declaration-list
variadic-declaration-list
simple-parameter-declaration-list:
parameter-declaration
parameter-declaration-list , parameter-declaration
variadic-declaration-list:
simple-parameter-declaration-list , variadic-parameter
variadic-parameter
parameter-declaration:
type-declarationopt &opt variable-name default-argument-specifieropt
variadic-parameter:
type-declarationopt &opt ... variable-name
return-type:
: type-declaration
: void
type-declaration:
array
callable
scalar-type
qualified-name
scalar-type:
bool
float
int
string
default-argument-specifier:
= constant-expression
###Classes
class-declaration:
class-modifieropt class name class-base-clauseopt class-interface-clauseopt { class-member-declarationsopt }
class-modifier:
abstract
final
class-base-clause:
extends qualified-name
class-interface-clause:
implements qualified-name
class-interface-clause , qualified-name
class-member-declarations:
class-member-declaration
class-member-declarations class-member-declaration
class-member-declaration:
class-const-declaration
property-declaration
method-declaration
constructor-declaration
destructor-declaration
trait-use-clause
const-declaration:
const const-elements ;
class-const-declaration:
visibility-modifieropt const const-elements ;
const-elements:
const-element
const-elements const-element
const-element:
name = constant-expression
property-declaration:
property-modifier property-elements ;
property-modifier:
var
visibility-modifier static-modifieropt
static-modifier visibility-modifieropt
visibility-modifier:
public
protected
private
static-modifier:
static
property-elements:
property-element
property-elements property-element
property-element:
variable-name property-initializeropt ;
property-initializer:
= constant-expression
method-declaration:
method-modifiersopt function-definition
method-modifiers function-definition-header ;
method-modifiers:
method-modifier
method-modifiers method-modifier
method-modifier:
visibility-modifier
static-modifier
class-modifier
constructor-declaration:
method-modifiers function &opt __construct ( parameter-declaration-listopt ) compound-statement
method-modifiers function &opt name ( parameter-declaration-listopt ) compound-statement [Deprecated form]
destructor-declaration:
method-modifiers function &opt __destruct ( ) compound-statement
###Interfaces
interface-declaration:
interface name interface-base-clauseopt { interface-member-declarationsopt }
interface-base-clause:
extends qualified-name
interface-base-clause , qualified-name
interface-member-declarations:
interface-member-declaration
interface-member-declarations interface-member-declaration
interface-member-declaration:
class-const-declaration
method-declaration
###Traits
trait-declaration:
trait name { trait-member-declarationsopt }
trait-member-declarations:
trait-member-declaration
trait-member-declarations trait-member-declaration
trait-member-declaration:
property-declaration
method-declaration
constructor-declaration
destructor-declaration
trait-use-clauses
trait-use-clauses:
trait-use-clause
trait-use-clauses trait-use-clause
trait-use-clause:
use trait-name-list trait-use-specification
trait-name-list:
qualified-name
trait-name-list , qualified-name
trait-use-specification:
;
{ trait-select-and-alias-clausesopt }
trait-select-and-alias-clauses:
trait-select-and-alias-clause
trait-select-and-alias-clauses trait-select-and-alias-clause
trait-select-and-alias-clause:
trait-select-insteadof-clause ;
trait-alias-as-clause ;
trait-select-insteadof-clause:
name insteadof name
trait-alias-as-clause:
name as visibility-modifieropt name
name as visibility-modifier nameopt
###Namespaces
namespace-definition:
namespace name ;
namespace nameopt compound-statement
namespace-use-declaration:
use namespace-function-or-constopt namespace-use-clauses ;
use namespace-function-or-const \opt namespace-name \
{ namespace-use-group-clauses-1 } ;
use \opt namespace-name \ { namespace-use-group-clauses-2 } ;
namespace-use-clauses:
namespace-use-clause
namespace-use-clauses , namespace-use-clause
namespace-use-clause:
qualified-name namespace-aliasing-clauseopt
namespace-aliasing-clause:
as name
namespace-function-or-const:
function
const
namespace-use-group-clauses-1:
namespace-use-group-clause-1
namespace-use-group-clauses-1 , namespace-use-group-clause-1
namespace-use-group-clause-1:
namespace-name namespace-aliasing-clauseopt
namespace-use-group-clauses-2:
namespace-use-group-clause-2
namespace-use-group-clauses-2 , namespace-use-group-clause-2
namespace-use-group-clause-2:
namespace-function-or-constopt namespace-name namespace-aliasing-clauseopt