glsl-es-3-grammar.txt

/*
   The grammar is fed from the output of lexical analysis. The tokens returned from lexical analysis are
   CONST BOOL FLOAT INT UINT
   BREAK CONTINUE DO ELSE FOR IF DISCARD RETURN SWITCH CASE DEFAULT
   BVEC2 BVEC3 BVEC4 IVEC2 IVEC3 IVEC4 UVEC2 UVEC3 UVEC4 VEC2 VEC3 VEC4
   MAT2 MAT3 MAT4 CENTROID IN OUT INOUT UNIFORM

   FLAT SMOOTH LAYOUT
   MAT2X2 MAT2X3 MAT2X4
   MAT3X2 MAT3X3 MAT3X4
   MAT4X2 MAT4X3 MAT4X4
   SAMPLER2D SAMPLER3D SAMPLERCUBE SAMPLER2DSHADOW
   SAMPLERCUBESHADOW SAMPLER2DARRAY
   SAMPLER2DARRAYSHADOW ISAMPLER2D ISAMPLER3D ISAMPLERCUBE
   ISAMPLER2DARRAY USAMPLER2D USAMPLER3D
   USAMPLERCUBE USAMPLER2DARRAY

   STRUCT VOID WHILE

   IDENTIFIER TYPE_NAME FLOATCONSTANT INTCONSTANT UINTCONSTANT BOOLCONSTANT
   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
   HIGH_PRECISION MEDIUM_PRECISION LOW_PRECISION PRECISION
*/

variable_identifier:
  IDENTIFIER

primary_expression:
  variable_identifier
  INTCONSTANT
  UINTCONSTANT
  FLOATCONSTANT
  BOOLCONSTANT
  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

integer_expression:
  expression

function_call:
  function_call_or_method

function_call_or_method:
  function_call_generic
  postfix_expression DOT 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) and identifiers are recognized through postfix_expression.

function_identifier:
  type_specifier
  IDENTIFIER
  FIELD_SELECTION

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_no_prec 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 LEFT_BRACKET constant_expression RIGHT_BRACKET SEMICOLON
    type_qualifier SEMICOLON

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 LEFT_BRACKET constant_expression RIGHT_BRACKET

parameter_declaration:
  parameter_type_qualifier parameter_qualifier parameter_declarator
  parameter_qualifier parameter_declarator
  parameter_type_qualifier parameter_qualifier parameter_type_specifier
  parameter_qualifier parameter_type_specifier

parameter_qualifier:
  /* empty */
  IN
  OUT
  INOUT

parameter_type_specifier:
  type_specifier

init_declarator_list:
  single_declaration
  init_declarator_list COMMA IDENTIFIER

  init_declarator_list COMMA IDENTIFIER LEFT_BRACKET constant_expression RIGHT_BRACKET
  init_declarator_list COMMA IDENTIFIER LEFT_BRACKET RIGHT_BRACKET EQUAL initializer
  init_declarator_list COMMA IDENTIFIER LEFT_BRACKET constant_expression RIGHT_BRACKET EQUAL initializer
  init_declarator_list COMMA IDENTIFIER EQUAL initializer

single_declaration:
  fully_specified_type
  fully_specified_type IDENTIFIER

  fully_specified_type IDENTIFIER LEFT_BRACKET constant_expression RIGHT_BRACKET
  fully_specified_type IDENTIFIER LEFT_BRACKET RIGHT_BRACKET EQUAL initializer
  fully_specified_type IDENTIFIER LEFT_BRACKET constant_expression RIGHT_BRACKET EQUAL initializer
  fully_specified_type IDENTIFIER EQUAL initializer
  INVARIANT IDENTIFIER

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

fully_specified_type:
  type_specifier
  type_qualifier type_specifier

invariant_qualifier:
  INVARIANT

interpolation_qualifier:
  SMOOTH
  FLAT

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 INTCONSTANT
  IDENTIFIER EQUAL UINTCONSTANT

parameter_type_qualifier:
  CONST

type_qualifier:
  storage_qualifier
  layout_qualifier
  layout_qualifier storage_qualifier
  interpolation_qualifier storage_qualifier
  interpolation_qualifier
  invariant_qualifier storage_qualifier
  invariant_qualifier interpolation_qualifier storage_qualifier

storage_qualifier:
  CONST
  IN
  OUT
  CENTROID IN
  CENTROID OUT
  UNIFORM

type_specifier:
  type_specifier_no_prec
  precision_qualifier type_specifier_no_prec

type_specifier_no_prec:
  type_specifier_nonarray
  type_specifier_nonarray LEFT_BRACKET RIGHT_BRACKET
  type_specifier_nonarray LEFT_BRACKET constant_expression RIGHT_BRACKET

type_specifier_nonarray:
  VOID
  FLOAT
  INT
  UINT
  BOOL
  VEC2
  VEC3
  VEC4
  BVEC2
  BVEC3
  BVEC4
  IVEC2
  IVEC3
  IVEC4
  UVEC2
  UVEC3
  UVEC4
  MAT2
  MAT3
  MAT4
  MAT2X2
  MAT2X3
  MAT2X4
  MAT3X2
  MAT3X3
  MAT3X4
  MAT4X2
  MAT4X3
  MAT4X4
  SAMPLER2D
  SAMPLER3D
  SAMPLERCUBE
  SAMPLER2DSHADOW
  SAMPLERCUBESHADOW
  SAMPLER2DARRAY
  SAMPLER2DARRAYSHADOW
  ISAMPLER2D
  ISAMPLER3D
  ISAMPLERCUBE
  ISAMPLER2DARRAY
  USAMPLER2D
  USAMPLER3D
  USAMPLERCUBE
  USAMPLER2DARRAY
  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 LEFT_BRACKET RIGHT_BRACKET
  IDENTIFIER LEFT_BRACKET constant_expression RIGHT_BRACKET

initializer:
  assignment_expression

declaration_statement:
  declaration

statement:
  compound_statement_with_scope
  simple_statement

statement_no_new_scope:
  compound_statement_no_new_scope
  simple_statement

statement_with_scope:
  compound_statement_no_new_scope
  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_with_scope:
  LEFT_BRACE RIGHT_BRACE
  LEFT_BRACE statement_list RIGHT_BRACE

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_with_scope ELSE statement_with_scope
  statement_with_scope

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:
  /* nothing */
  statement_list

case_label:
  CASE expression COLON
  DEFAULT COLON

iteration_statement:
  WHILE LEFT_PAREN condition RIGHT_PAREN statement_no_new_scope
  DO statement_with_scope 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:
  condition
  /* empty */

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

function_definition:
  function_prototype compound_statement_no_new_scope