Shading Language Grammar

The grammar is fed from the output of lexical analysis. The tokens returned from lexical analysis are

Token Name GLSL

Token Name	GLSL
CONST	`const`
BOOL	`bool`
FLOAT	`float`
INT	`int`
UINT	`uint`
DOUBLE	`double`

BVEC2	`bvec2`
BVEC3	`bvec3`
BVEC4	`bvec4`
IVEC2	`ivec2`
IVEC3	`ivec3`
IVEC4	`ivec4`
UVEC2	`uvec2`
UVEC3	`uvec3`
UVEC4	`uvec4`
VEC2	`vec2`
VEC3	`vec3`
VEC4	`vec4`

MAT2	`mat2`
MAT3	`mat3`
MAT4	`mat4`
MAT2X2	`mat2x2`
MAT2X3	`mat2x3`
MAT2X4	`mat2x4`
MAT3X2	`mat3x2`
MAT3X3	`mat3x3`
MAT3X4	`mat3x4`
MAT4X2	`mat4x2`
MAT4X3	`mat4x3`
MAT4X4	`mat4x4`

DVEC2	`dvec2`
DVEC3	`dvec3`
DVEC4	`dvec4`
DMAT2	`dmat2`
DMAT3	`dmat3`
DMAT4	`dmat4`
DMAT2X2	`dmat2x2`
DMAT2X3	`dmat2x3`
DMAT2X4	`dmat2x4`
DMAT3X2	`dmat3x2`
DMAT3X3	`dmat3x3`
DMAT3X4	`dmat3x4`
DMAT4X2	`dmat4x2`
DMAT4X3	`dmat4x3`
DMAT4X4	`dmat4x4`

CENTROID	`centroid`
IN	`in`
OUT	`out`
INOUT	`inout`
UNIFORM	`uniform`
PATCH	`patch`
SAMPLE	`sample`
BUFFER	`buffer`
SHARED	`shared`
COHERENT	`coherent`
VOLATILE	`volatile`
RESTRICT	`restrict`
READONLY	`readonly`
WRITEONLY	`writeonly`
NOPERSPECTIVE	`noperspective`
FLAT	`flat`
SMOOTH	`smooth`
LAYOUT	`layout`

ATOMIC_UINT	`atomic_uint`

SAMPLER2D	`sampler2D`
SAMPLER3D	`sampler3D`
SAMPLERCUBE	`samplerCube`
SAMPLER2DSHADOW	`sampler2DShadow`
SAMPLERCUBESHADOW	`samplerCubeShadow`
SAMPLER2DARRAY	`sampler2DArray`
SAMPLER2DARRAYSHADOW	`sampler2DArrayShadow`
ISAMPLER2D	`isampler2D`
ISAMPLER3D	`isampler3D`
ISAMPLERCUBE	`isamplerCube`
ISAMPLER2DARRAY	`isampler2DArray`
USAMPLER2D	`usampler2D`
USAMPLER3D	`usampler3D`
USAMPLERCUBE	`usamplerCube`
USAMPLER2DARRAY	`usampler2DArray`

SAMPLER1D	`sampler1D`
SAMPLER1DSHADOW	`sampler1DShadow`
SAMPLER1DARRAY	`sampler1DArray`
SAMPLER1DARRAYSHADOW	`sampler1DArrayShadow`
ISAMPLER1D	`isampler1D`
ISAMPLER1DARRAY	`isampler1DArray`
USAMPLER1D	`usampler1D`
USAMPLER1DARRAY	`usampler1DArray`
SAMPLER2DRECT	`sampler2DRect`
SAMPLER2DRECTSHADOW	`sampler2DRectShadow`
ISAMPLER2DRECT	`isampler2DRect`
USAMPLER2DRECT	`usampler2DRect`

SAMPLERBUFFER	`samplerBuffer`
ISAMPLERBUFFER	`isamplerBuffer`
USAMPLERBUFFER	`usamplerBuffer`
SAMPLERCUBEARRAY	`samplerCubeArray`
SAMPLERCUBEARRAYSHADOW	`samplerCubeArrayShadow`
ISAMPLERCUBEARRAY	`isamplerCubeArray`
USAMPLERCUBEARRAY	`usamplerCubeArray`
SAMPLER2DMS	`sampler2DMS`
ISAMPLER2DMS	`isampler2DMS`
USAMPLER2DMS	`usampler2DMS`
SAMPLER2DMSARRAY	`sampler2DMSArray`
ISAMPLER2DMSARRAY	`isampler2DMSArray`
USAMPLER2DMSARRAY	`usampler2DMSArray`
IMAGE2D	`image2D`
IIMAGE2D	`iimage2D`
UIMAGE2D	`uimage2D`
IMAGE3D	`image3D`
IIMAGE3D	`iimage3D`
UIMAGE3D	`uimage3D`
IMAGECUBE	`imageCube`
IIMAGECUBE	`iimageCube`
UIMAGECUBE	`uimageCube`
IMAGEBUFFER	`imageBuffer`
IIMAGEBUFFER	`iimageBuffer`
UIMAGEBUFFER	`uimageBuffer`
IMAGE2DARRAY	`image2DArray`
IIMAGE2DARRAY	`iimage2DArray`
UIMAGE2DARRAY	`uimage2DArray`
IMAGECUBEARRAY	`imageCubeArray`
IIMAGECUBEARRAY	`iimageCubeArray`
UIMAGECUBEARRAY	`uimageCubeArray`

IMAGE1D	`image1D`
IIMAGE1D	`iimage1D`
UIMAGE1D	`uimage1D`
IMAGE1DARRAY	`image1DArray`
IIMAGE1DARRAY	`iimage1DArray`
UIMAGE1DARRAY	`uimage1DArray`
IMAGE2DRECT	`image2DRect`
IIMAGE2DRECT	`iimage2DRect`
UIMAGE2DRECT	`uimage2DRect`
IMAGE2DMS	`image2DMS`
IIMAGE2DMS	`iimage2DMS`
UIMAGE2DMS	`uimage2DMS`
IMAGE2DMSARRAY	`image2DMSArray`
IIMAGE2DMSARRAY	`iimage2DMSArray`
UIMAGE2DMSARRAY	`uimage2DMSArray`

STRUCT	`struct`
VOID	`void`

WHILE	`while`
BREAK	`break`
CONTINUE	`continue`
DO	`do`
ELSE	`else`
FOR	`for`
IF	`if`
DISCARD	`discard`
RETURN	`return`
SWITCH	`switch`
CASE	`case`
DEFAULT	`default`
SUBROUTINE	`subroutine`

IDENTIFIER	Identifiers
TYPE_NAME	Identifiers
FLOATCONSTANT	Floats
INTCONSTANT	Integers
UINTCONSTANT	Integers
BOOLCONSTANT	Booleans
DOUBLECONSTANT	Floats
FIELD_SELECTION	Identifiers

LEFT_OP	`<<`
RIGHT_OP	`>>`
INC_OP	`++`
DEC_OP	`--`
LE_OP	`<=`
GE_OP	`>=`
EQ_OP	`==`
NE_OP	`!=`
AND_OP	`&&`
OR_OP	`\|\|`
XOR_OP	`^^`
MUL_ASSIGN	`*=`
DIV_ASSIGN	`/=`
ADD_ASSIGN	`+=`
MOD_ASSIGN	`%=`
LEFT_ASSIGN	`<<=`
RIGHT_ASSIGN	`>>=`
AND_ASSIGN	`&=`
XOR_ASSIGN	`^=`
OR_ASSIGN	`\|=`
SUB_ASSIGN	`-=`
LEFT_PAREN	`(`
RIGHT_PAREN	`)`
LEFT_BRACKET	`[`
RIGHT_BRACKET	`]`
LEFT_BRACE	`{`
RIGHT_BRACE	`}`
DOT	`.`
COMMA	`,`
COLON	`:`
EQUAL	`=`
SEMICOLON	`;`
BANG	`!`
DASH	`-`
TILDE	`~`
PLUS	`+`
STAR	`*`
SLASH	`/`
PERCENT	`%`
LEFT_ANGLE	`<`
RIGHT_ANGLE	`>`
VERTICAL_BAR	`\|`
CARET	`^`
AMPERSAND	`&`
QUESTION	`?`

INVARIANT	`invariant`
PRECISE	`precise`
HIGH_PRECISION	`highp`
MEDIUM_PRECISION	`mediump`
LOW_PRECISION	`lowp`
PRECISION	`precision`

CONST

const

BOOL

bool

FLOAT

float

INT

int

UINT

uint

DOUBLE

double

BVEC2

bvec2

BVEC3

bvec3

BVEC4

bvec4

IVEC2

ivec2

IVEC3

ivec3

IVEC4

ivec4

UVEC2

uvec2

UVEC3

uvec3

UVEC4

uvec4

VEC2

vec2

VEC3

vec3

VEC4

vec4

MAT2

mat2

MAT3

mat3

MAT4

mat4

MAT2X2

mat2x2

MAT2X3

mat2x3

MAT2X4

mat2x4

MAT3X2

mat3x2

MAT3X3

mat3x3

MAT3X4

mat3x4

MAT4X2

mat4x2

MAT4X3

mat4x3

MAT4X4

mat4x4

DVEC2

dvec2

DVEC3

dvec3

DVEC4

dvec4

DMAT2

dmat2

DMAT3

dmat3

DMAT4

dmat4

DMAT2X2

dmat2x2

DMAT2X3

dmat2x3

DMAT2X4

dmat2x4

DMAT3X2

dmat3x2

DMAT3X3

dmat3x3

DMAT3X4

dmat3x4

DMAT4X2

dmat4x2

DMAT4X3

dmat4x3

DMAT4X4

dmat4x4

CENTROID

centroid

in

OUT

out

INOUT

inout

UNIFORM

uniform

PATCH

patch

SAMPLE

sample

BUFFER

buffer

SHARED

shared

COHERENT

coherent

VOLATILE

volatile

RESTRICT

restrict

READONLY

readonly

WRITEONLY

writeonly

NOPERSPECTIVE

noperspective

FLAT

flat

SMOOTH

smooth

LAYOUT

layout

ATOMIC_UINT

atomic_uint

SAMPLER2D

sampler2D

SAMPLER3D

sampler3D

SAMPLERCUBE

samplerCube

SAMPLER2DSHADOW

sampler2DShadow

SAMPLERCUBESHADOW

samplerCubeShadow

SAMPLER2DARRAY

sampler2DArray

SAMPLER2DARRAYSHADOW

sampler2DArrayShadow

ISAMPLER2D

isampler2D

ISAMPLER3D

isampler3D

ISAMPLERCUBE

isamplerCube

ISAMPLER2DARRAY

isampler2DArray

USAMPLER2D

usampler2D

USAMPLER3D

usampler3D

USAMPLERCUBE

usamplerCube

USAMPLER2DARRAY

usampler2DArray

SAMPLER1D

sampler1D

SAMPLER1DSHADOW

sampler1DShadow

SAMPLER1DARRAY

sampler1DArray

SAMPLER1DARRAYSHADOW

sampler1DArrayShadow

ISAMPLER1D

isampler1D

ISAMPLER1DARRAY

isampler1DArray

USAMPLER1D

usampler1D

USAMPLER1DARRAY

usampler1DArray

SAMPLER2DRECT

sampler2DRect

SAMPLER2DRECTSHADOW

sampler2DRectShadow

ISAMPLER2DRECT

isampler2DRect

USAMPLER2DRECT

usampler2DRect

SAMPLERBUFFER

samplerBuffer

ISAMPLERBUFFER

isamplerBuffer

USAMPLERBUFFER

usamplerBuffer

SAMPLERCUBEARRAY

samplerCubeArray

SAMPLERCUBEARRAYSHADOW

samplerCubeArrayShadow

ISAMPLERCUBEARRAY

isamplerCubeArray

USAMPLERCUBEARRAY

usamplerCubeArray

SAMPLER2DMS

sampler2DMS

ISAMPLER2DMS

isampler2DMS

USAMPLER2DMS

usampler2DMS

SAMPLER2DMSARRAY

sampler2DMSArray

ISAMPLER2DMSARRAY

isampler2DMSArray

USAMPLER2DMSARRAY

usampler2DMSArray

IMAGE2D

image2D

IIMAGE2D

iimage2D

UIMAGE2D

uimage2D

IMAGE3D

image3D

IIMAGE3D

iimage3D

UIMAGE3D

uimage3D

IMAGECUBE

imageCube

IIMAGECUBE

iimageCube

UIMAGECUBE

uimageCube

IMAGEBUFFER

imageBuffer

IIMAGEBUFFER

iimageBuffer

UIMAGEBUFFER

uimageBuffer

IMAGE2DARRAY

image2DArray

IIMAGE2DARRAY

iimage2DArray

UIMAGE2DARRAY

uimage2DArray

IMAGECUBEARRAY

imageCubeArray

IIMAGECUBEARRAY

iimageCubeArray

UIMAGECUBEARRAY

uimageCubeArray

IMAGE1D

image1D

IIMAGE1D

iimage1D

UIMAGE1D

uimage1D

IMAGE1DARRAY

image1DArray

IIMAGE1DARRAY

iimage1DArray

UIMAGE1DARRAY

uimage1DArray

IMAGE2DRECT

image2DRect

IIMAGE2DRECT

iimage2DRect

UIMAGE2DRECT

uimage2DRect

IMAGE2DMS

image2DMS

IIMAGE2DMS

iimage2DMS

UIMAGE2DMS

uimage2DMS

IMAGE2DMSARRAY

image2DMSArray

IIMAGE2DMSARRAY

iimage2DMSArray

UIMAGE2DMSARRAY

uimage2DMSArray

STRUCT

struct

VOID

void

WHILE

while

BREAK

break

CONTINUE

continue

do

ELSE

else

FOR

for

if

DISCARD

discard

RETURN

return

SWITCH

switch

CASE

case

DEFAULT

default

SUBROUTINE

subroutine

IDENTIFIER

TYPE_NAME

FLOATCONSTANT

INTCONSTANT

UINTCONSTANT

BOOLCONSTANT

DOUBLECONSTANT

FIELD_SELECTION

LEFT_OP

<<

RIGHT_OP

>>

INC_OP

++

DEC_OP

--

LE_OP

<=

GE_OP

>=

EQ_OP

==

NE_OP

!=

AND_OP

&&

OR_OP

||

XOR_OP

^^

MUL_ASSIGN

*=

DIV_ASSIGN

/=

ADD_ASSIGN

+=

MOD_ASSIGN

%=

LEFT_ASSIGN

<<=

RIGHT_ASSIGN

>>=

AND_ASSIGN

&=

XOR_ASSIGN

^=

OR_ASSIGN

|=

SUB_ASSIGN

-=

LEFT_PAREN

(

RIGHT_PAREN

)

LEFT_BRACKET

[

RIGHT_BRACKET

]

LEFT_BRACE

{

RIGHT_BRACE

}

DOT

.

COMMA

,

COLON

:

EQUAL

=

SEMICOLON

;

BANG

!

DASH

-

TILDE

~

PLUS

+

STAR

*

SLASH

/

PERCENT

%

LEFT_ANGLE

<

RIGHT_ANGLE

>

VERTICAL_BAR

|

CARET

^

AMPERSAND

&

QUESTION

?

INVARIANT

invariant

PRECISE

precise

HIGH_PRECISION

highp

MEDIUM_PRECISION

mediump

LOW_PRECISION

lowp

PRECISION

precision

The following describes the grammar for the OpenGL Shading Language in terms of the above tokens. The starting rule is translation_unit. An empty shader (one having no tokens to parse, after pre-processing) is valid, resulting in no compile-time errors, even though the grammar below does not have a rule to accept an empty token stream.

variable_identifier :: IDENTIFIER
primary_expression :: variable_identifier
INTCONSTANT
UINTCONSTANT
FLOATCONSTANT
BOOLCONSTANT
DOUBLECONSTANT
LEFT_PAREN expression RIGHT_PAREN
postfix_expression :: primary_expression
postfix_expression LEFT_BRACKET integer_expression RIGHT_BRACKET
function_call
postfix_expression DOT FIELD_SELECTION
postfix_expression INC_OP
postfix_expression DEC_OP

FIELD_SELECTION includes members in structures, component selection for vectors and the 'length' identifier for the length() method

integer_expression :: expression
function_call :: function_call_or_method
function_call_or_method :: function_call_generic
function_call_generic :: function_call_header_with_parameters RIGHT_PAREN
function_call_header_no_parameters RIGHT_PAREN
function_call_header_no_parameters :: function_call_header VOID
function_call_header
function_call_header_with_parameters :: function_call_header assignment_expression
function_call_header_with_parameters COMMA assignment_expression
function_call_header :: function_identifier LEFT_PAREN

Grammar Note: Constructors look like functions, but lexical analysis recognized most of them as keywords. They are now recognized through type_specifier.

Methods (.length), subroutine array calls, and identifiers are recognized through postfix_expression.

function_identifier :: type_specifier
postfix_expression
unary_expression :: postfix_expression
INC_OP unary_expression
DEC_OP unary_expression
unary_operator unary_expression

Grammar Note: No traditional style type casts.

unary_operator :: PLUS
DASH
BANG
TILDE

Grammar Note: No '*' or '&' unary ops. Pointers are not supported.

multiplicative_expression :: unary_expression
multiplicative_expression STAR unary_expression
multiplicative_expression SLASH unary_expression
multiplicative_expression PERCENT unary_expression
additive_expression :: multiplicative_expression
additive_expression PLUS multiplicative_expression
additive_expression DASH multiplicative_expression
shift_expression :: additive_expression
shift_expression LEFT_OP additive_expression
shift_expression RIGHT_OP additive_expression
relational_expression :: shift_expression
relational_expression LEFT_ANGLE shift_expression
relational_expression RIGHT_ANGLE shift_expression
relational_expression LE_OP shift_expression
relational_expression GE_OP shift_expression
equality_expression :: relational_expression
equality_expression EQ_OP relational_expression
equality_expression NE_OP relational_expression
and_expression :: equality_expression
and_expression AMPERSAND equality_expression
exclusive_or_expression :: and_expression
exclusive_or_expression CARET and_expression
inclusive_or_expression :: exclusive_or_expression
inclusive_or_expression VERTICAL_BAR exclusive_or_expression
logical_and_expression :: inclusive_or_expression
logical_and_expression AND_OP inclusive_or_expression
logical_xor_expression :: logical_and_expression
logical_xor_expression XOR_OP logical_and_expression
logical_or_expression :: logical_xor_expression
logical_or_expression OR_OP logical_xor_expression
conditional_expression :: logical_or_expression
logical_or_expression QUESTION expression COLON assignment_expression
assignment_expression :: conditional_expression
unary_expression assignment_operator assignment_expression
assignment_operator :: EQUAL
MUL_ASSIGN
DIV_ASSIGN
MOD_ASSIGN
ADD_ASSIGN
SUB_ASSIGN
LEFT_ASSIGN
RIGHT_ASSIGN
AND_ASSIGN
XOR_ASSIGN
OR_ASSIGN
expression :: assignment_expression
expression COMMA assignment_expression
constant_expression :: conditional_expression
declaration :: function_prototype SEMICOLON
init_declarator_list SEMICOLON
PRECISION precision_qualifier type_specifier SEMICOLON
type_qualifier IDENTIFIER LEFT_BRACE struct_declaration_list RIGHT_BRACE SEMICOLON
type_qualifier IDENTIFIER LEFT_BRACE struct_declaration_list RIGHT_BRACE IDENTIFIER SEMICOLON
type_qualifier IDENTIFIER LEFT_BRACE struct_declaration_list RIGHT_BRACE IDENTIFIER array_specifier SEMICOLON
type_qualifier SEMICOLON
type_qualifier identifier_list SEMICOLON
identifier_list :: IDENTIFIER
identifier_list COMMA IDENTIFIER
function_prototype :: function_declarator RIGHT_PAREN
function_declarator :: function_header
function_header_with_parameters
function_header_with_parameters :: function_header parameter_declaration
function_header_with_parameters COMMA parameter_declaration
function_header :: fully_specified_type IDENTIFIER LEFT_PAREN
parameter_declarator :: type_specifier IDENTIFIER
type_specifier IDENTIFIER array_specifier
parameter_declaration :: type_qualifier parameter_declarator
parameter_declarator
type_qualifier parameter_type_specifier
parameter_type_specifier
parameter_type_specifier :: type_specifier
init_declarator_list :: single_declaration
init_declarator_list COMMA IDENTIFIER
init_declarator_list COMMA IDENTIFIER array_specifier
init_declarator_list COMMA IDENTIFIER array_specifier EQUAL initializer
init_declarator_list COMMA IDENTIFIER EQUAL initializer
single_declaration :: fully_specified_type
fully_specified_type IDENTIFIER
fully_specified_type IDENTIFIER array_specifier
fully_specified_type IDENTIFIER array_specifier EQUAL initializer
fully_specified_type IDENTIFIER EQUAL initializer

Grammar Note: No 'enum', or 'typedef'.

fully_specified_type :: type_specifier
type_qualifier type_specifier
invariant_qualifier :: INVARIANT
interpolation_qualifier :: SMOOTH
FLAT
NOPERSPECTIVE
layout_qualifier :: LAYOUT LEFT_PAREN layout_qualifier_id_list RIGHT_PAREN
layout_qualifier_id_list :: layout_qualifier_id
layout_qualifier_id_list COMMA layout_qualifier_id
layout_qualifier_id :: IDENTIFIER
IDENTIFIER EQUAL constant_expression
SHARED
precise_qualifier :: PRECISE
type_qualifier :: single_type_qualifier
type_qualifier single_type_qualifier
single_type_qualifier :: storage_qualifier
layout_qualifier
precision_qualifier
interpolation_qualifier
invariant_qualifier
precise_qualifier
storage_qualifier :: CONST
IN
OUT
INOUT
CENTROID
PATCH
SAMPLE
UNIFORM
BUFFER
SHARED
COHERENT
VOLATILE
RESTRICT
READONLY
WRITEONLY
SUBROUTINE
SUBROUTINE LEFT_PAREN type_name_list RIGHT_PAREN
type_name_list :: TYPE_NAME
type_name_list COMMA TYPE_NAME
type_specifier :: type_specifier_nonarray
type_specifier_nonarray array_specifier

array_specifier :: LEFT_BRACKET RIGHT_BRACKET
LEFT_BRACKET conditional_expression RIGHT_BRACKET
array_specifier LEFT_BRACKET RIGHT_BRACKET
array_specifier LEFT_BRACKET conditional_expression RIGHT_BRACKET

type_specifier_nonarray :: VOID
FLOAT
DOUBLE
INT
UINT
BOOL
VEC2
VEC3
VEC4
DVEC2
DVEC3
DVEC4
BVEC2
BVEC3
BVEC4
IVEC2
IVEC3
IVEC4
UVEC2
UVEC3
UVEC4
MAT2
MAT3
MAT4
MAT2X2
MAT2X3
MAT2X4
MAT3X2
MAT3X3
MAT3X4
MAT4X2
MAT4X3
MAT4X4
DMAT2
DMAT3
DMAT4
DMAT2X2
DMAT2X3
DMAT2X4
DMAT3X2
DMAT3X3
DMAT3X4
DMAT4X2
DMAT4X3
DMAT4X4
ATOMIC_UINT
SAMPLER2D
SAMPLER3D
SAMPLERCUBE
SAMPLER2DSHADOW
SAMPLERCUBESHADOW
SAMPLER2DARRAY
SAMPLER2DARRAYSHADOW
SAMPLERCUBEARRAY
SAMPLERCUBEARRAYSHADOW
ISAMPLER2D
ISAMPLER3D
ISAMPLERCUBE
ISAMPLER2DARRAY
ISAMPLERCUBEARRAY
USAMPLER2D
USAMPLER3D
USAMPLERCUBE
USAMPLER2DARRAY
USAMPLERCUBEARRAY
SAMPLER1D
SAMPLER1DSHADOW
SAMPLER1DARRAY
SAMPLER1DARRAYSHADOW
ISAMPLER1D
ISAMPLER1DARRAY
USAMPLER1D
USAMPLER1DARRAY
SAMPLER2DRECT
SAMPLER2DRECTSHADOW
ISAMPLER2DRECT
USAMPLER2DRECT
SAMPLERBUFFER
ISAMPLERBUFFER
USAMPLERBUFFER
SAMPLER2DMS
ISAMPLER2DMS
USAMPLER2DMS
SAMPLER2DMSARRAY
ISAMPLER2DMSARRAY
USAMPLER2DMSARRAY
IMAGE2D
IIMAGE2D
UIMAGE2D
IMAGE3D
IIMAGE3D
UIMAGE3D
IMAGECUBE
IIMAGECUBE
UIMAGECUBE
IMAGEBUFFER
IIMAGEBUFFER
UIMAGEBUFFER
IMAGE1D
IIMAGE1D
UIMAGE1D
IMAGE1DARRAY
IIMAGE1DARRAY
UIMAGE1DARRAY
IMAGE2DRECT
IIMAGE2DRECT
UIMAGE2DRECT
IMAGE2DARRAY
IIMAGE2DARRAY
UIMAGE2DARRAY
IMAGECUBEARRAY
IIMAGECUBEARRAY
UIMAGECUBEARRAY
IMAGE2DMS
IIMAGE2DMS
UIMAGE2DMS
IMAGE2DMSARRAY
IIMAGE2DMSARRAY
UIMAGE2DMSARRAY
struct_specifier
TYPE_NAME
precision_qualifier :: HIGH_PRECISION
MEDIUM_PRECISION
LOW_PRECISION
struct_specifier :: STRUCT IDENTIFIER LEFT_BRACE struct_declaration_list RIGHT_BRACE
STRUCT LEFT_BRACE struct_declaration_list RIGHT_BRACE
struct_declaration_list :: struct_declaration
struct_declaration_list struct_declaration
struct_declaration :: type_specifier struct_declarator_list SEMICOLON
type_qualifier type_specifier struct_declarator_list SEMICOLON
struct_declarator_list :: struct_declarator
struct_declarator_list COMMA struct_declarator
struct_declarator :: IDENTIFIER
IDENTIFIER array_specifier
initializer :: assignment_expression
LEFT_BRACE initializer_list RIGHT_BRACE
LEFT_BRACE initializer_list COMMA RIGHT_BRACE
initializer_list :: initializer
initializer_list COMMA initializer
declaration_statement :: declaration
statement :: compound_statement
simple_statement

Grammar Note: labeled statements for SWITCH only; 'goto' is not supported.

simple_statement :: declaration_statement
expression_statement
selection_statement
switch_statement
case_label
iteration_statement
jump_statement
compound_statement :: LEFT_BRACE RIGHT_BRACE
LEFT_BRACE statement_list RIGHT_BRACE
statement_no_new_scope :: compound_statement_no_new_scope
simple_statement
compound_statement_no_new_scope :: LEFT_BRACE RIGHT_BRACE
LEFT_BRACE statement_list RIGHT_BRACE
statement_list :: statement
statement_list statement
expression_statement :: SEMICOLON
expression SEMICOLON
selection_statement :: IF LEFT_PAREN expression RIGHT_PAREN selection_rest_statement
selection_rest_statement :: statement ELSE statement
statement
condition :: expression
fully_specified_type IDENTIFIER EQUAL initializer
switch_statement :: SWITCH LEFT_PAREN expression RIGHT_PAREN LEFT_BRACE switch_statement_list
RIGHT_BRACE
switch_statement_list :: /* empty */
statement_list
case_label :: CASE expression COLON
DEFAULT COLON
iteration_statement :: WHILE LEFT_PAREN condition RIGHT_PAREN statement_no_new_scope
DO statement WHILE LEFT_PAREN expression RIGHT_PAREN SEMICOLON
FOR LEFT_PAREN for_init_statement for_rest_statement RIGHT_PAREN statement_no_new_scope
for_init_statement :: expression_statement
declaration_statement
conditionopt :: /* empty */
condition
for_rest_statement :: conditionopt SEMICOLON
conditionopt SEMICOLON expression
jump_statement :: CONTINUE SEMICOLON
BREAK SEMICOLON
RETURN SEMICOLON
RETURN expression SEMICOLON
DISCARD SEMICOLON // Fragment shader only.

Grammar Note: No 'goto'. Gotos are not supported.

translation_unit :: external_declaration
translation_unit external_declaration
external_declaration :: function_definition
declaration
SEMICOLON
function_definition :: function_prototype compound_statement_no_new_scope

In general the above grammar describes a super set of the OpenGL Shading Language. Certain constructs that are valid purely in terms of the grammar are disallowed by statements elsewhere in this specification.