ast

package
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 Go to latest Published: Aug 29, 2017 License: Apache-2.0 Imports: 5 Imported by: 0

Documentation

Overview

Package ast defines the abstract syntax tree of OpenGL ES Shading Language programs.

It contains classes for individual types of expressions, statements and declarations. The code manipulating (parsing, serializing, evaluating, ...) the AST are located in other packages.

The type Ast represents the entire parsed program tree. It consists of a sequence of declarations (types ***Decl), which can be variable, function, interface declarations, etc.

Function bodies consist of a list of statements (types ***Stmt), for if, while, for statements, etc. There are two special kinds of statements: DeclarationStmt is a statement holding a declaration (described above) and ExpressionStmt is a statement holding an expression.

The expressions of the program are represented by types ***Expr. Typical examples are binary expressions, function call expressions, variable reference expressions, etc.

The AST contains enough information to enable serialization to text while preserving all whitespace and comments. The ***Cst members in all AST nodes are used for storing this whitespace information. This way, whitespace gets automatically preserved during AST modification. It is not necessary (but is possible) to populate the ***Cst members when creating new nodes, as the serialization is expected to succeed even without them.

The package also defines the type system of the GLES Shading Language programs (***Type), their values (***Value) and several helper functions for manipulating them.

Index

Constants

This section is empty.

Variables

View Source 
var (
	BoAdd    = appendBinaryOperator("+")
	BoBand   = appendBinaryOperator("&")
	BoBor    = appendBinaryOperator("|")
	BoBxor   = appendBinaryOperator("^")
	BoComma  = appendBinaryOperator(",")
	BoDiv    = appendBinaryOperator("/")
	BoEq     = appendBinaryOperator("==")
	BoLand   = appendBinaryOperator("&&")
	BoLess   = appendBinaryOperator("<")
	BoLessEq = appendBinaryOperator("<=")
	BoLor    = appendBinaryOperator("||")
	BoLxor   = appendBinaryOperator("^^")
	BoMod    = appendBinaryOperator("%")
	BoMore   = appendBinaryOperator(">")
	BoMoreEq = appendBinaryOperator(">=")
	BoMul    = appendBinaryOperator("*")
	BoNotEq  = appendBinaryOperator("!=")
	BoShl    = appendBinaryOperator("<<")
	BoShr    = appendBinaryOperator(">>")
	BoSub    = appendBinaryOperator("-")

	BoAssign    = appendAssignOp("=")
	BoAddAssign = appendAssignOp("+=")
	BoAndAssign = appendAssignOp("&=")
	BoDivAssign = appendAssignOp("/=")
	BoModAssign = appendAssignOp("%=")
	BoMulAssign = appendAssignOp("*=")
	BoOrAssign  = appendAssignOp("|=")
	BoShlAssign = appendAssignOp("<<=")
	BoShrAssign = appendAssignOp(">>=")
	BoSubAssign = appendAssignOp("-=")
	BoXorAssign = appendAssignOp("^=")

	UoBnot    = appendPrefixOp("~")
	UoLnot    = appendPrefixOp("!")
	UoMinus   = appendPrefixOp("-")
	UoPlus    = appendPrefixOp("+")
	UoPredec  = appendPrefixOp("--")
	UoPreinc  = appendPrefixOp("++")
	UoPostdec = appendUnaryOperator("--")
	UoPostinc = appendUnaryOperator("++")
)

All the operators of the language, one variable per operator.

View Source 
var (
	TVoid                 = appendType("void")
	TFloat                = appendType("float")
	TInt                  = appendType("int")
	TUint                 = appendType("uint")
	TBool                 = appendType("bool")
	TMat2                 = appendType("mat2")
	TMat3                 = appendType("mat3")
	TMat4                 = appendType("mat4")
	TMat2x2               = appendType("mat2x2")
	TMat2x3               = appendType("mat2x3")
	TMat2x4               = appendType("mat2x4")
	TMat3x2               = appendType("mat3x2")
	TMat3x3               = appendType("mat3x3")
	TMat3x4               = appendType("mat3x4")
	TMat4x2               = appendType("mat4x2")
	TMat4x3               = appendType("mat4x3")
	TMat4x4               = appendType("mat4x4")
	TVec2                 = appendType("vec2")
	TVec3                 = appendType("vec3")
	TVec4                 = appendType("vec4")
	TIvec2                = appendType("ivec2")
	TIvec3                = appendType("ivec3")
	TIvec4                = appendType("ivec4")
	TBvec2                = appendType("bvec2")
	TBvec3                = appendType("bvec3")
	TBvec4                = appendType("bvec4")
	TUvec2                = appendType("uvec2")
	TUvec3                = appendType("uvec3")
	TUvec4                = appendType("uvec4")
	TSampler2D            = appendType("sampler2D")
	TSampler3D            = appendType("sampler3D")
	TSamplerCube          = appendType("samplerCube")
	TSampler2DShadow      = appendType("sampler2DShadow")
	TSamplerCubeShadow    = appendType("samplerCubeShadow")
	TSampler2DArray       = appendType("sampler2DArray")
	TSampler2DArrayShadow = appendType("sampler2DArrayShadow")
	TSamplerExternalOES   = appendType("samplerExternalOES")
	TIsampler2D           = appendType("isampler2D")
	TIsampler3D           = appendType("isampler3D")
	TIsamplerCube         = appendType("isamplerCube")
	TIsampler2DArray      = appendType("isampler2DArray")
	TUsampler2D           = appendType("usampler2D")
	TUsampler3D           = appendType("usampler3D")
	TUsamplerCube         = appendType("usamplerCube")
	TUsampler2DArray      = appendType("usampler2DArray")

	// ARB_texture_multisample
	TSampler2DMS        = appendType("sampler2DMS")
	TIsampler2DMS       = appendType("isampler2DMS")
	TUssampler2DMS      = appendType("ussampler2DMS")
	TSampler2DMSArray   = appendType("sampler2DMSArray")
	TIsampler2DMSArray  = appendType("isampler2DMSArray")
	TUssampler2DMSArray = appendType("ussampler2DMSArray")
)

All types of the language.

View Source 
var BareTypes []BareType

All bare types of the language, in an array. Do not modify.

View Source 
var Operators []fmt.Stringer

All operators of the language, in an array, sorted according to string length (longest first). Do not modify.

Functions

func ConcatErrors 

func ConcatErrors(e1, e2 []error) []error

Concat concatenates two lists of errors.

func HasVectorExpansions 

func HasVectorExpansions(t BareType) bool

HasVectorExpansions returns true if the type t has corresponding vector counterparts. This is currently true only for TBool, TFloat, TInt and TUint.

func IsAssignmentOp 

func IsAssignmentOp(op BinaryOp) bool

Is op an assignment operator?

func IsMatrixType 

func IsMatrixType(t BareType) bool

IsMatrixType returns true if t is a matrix type.

func IsVectorType 

func IsVectorType(t BareType) bool

IsVectorType returns true if the given type is a vector type.

func TransformChildren 

func TransformChildren(n interface{}, v ChildTransformer)

TransformChildren is a helper function which calls the provided callback for each child node of the argument, replacing their values with the values returned from v.

func TypeDimensions 

func TypeDimensions(t BareType) (col uint8, row uint8)

TypeDimensions returns the number of columns and rows a given type contains. Vectors are treated as column vectors (cols == 1). Scalars have 1 column and 1 row.

func ValueEquals 

func ValueEquals(left, right Value) bool

ValueEquals compares two values for equality. The syntax of the GLES Shading Language does not permit comparing function values and this function will always return false for them.

func VisitChildren 

func VisitChildren(n interface{}, v ChildVisitor)

VisitChildren is a helper function which calls the provided callback for each child node of the argument.

Types

type ArrayType 

type ArrayType struct {
	Base Type
	Size Expression

	LBracketCst *parse.Leaf
	RBracketCst *parse.Leaf

	ComputedSize UintValue // The size determined by semantic analysis.
}

ArrayType represents array types. Size is represented as an expression. Unspecified size is represented by a nil expression. After semantic analysis, the ComputedSize field will store the size of the array as an integer. This size will be determined by evaluating the size expression, or from context. Precision getters and setters use the precision of the Base type.

func (*ArrayType) Copy 

func (at *ArrayType) Copy() *ArrayType

Copy returns a (shallow) copy of the underlying object.

func (*ArrayType) Equal 

func (at *ArrayType) Equal(other Type) bool

Equal determines whether two objects represent the same type. Note that a semantic analysis pass over the AST (to populate ComputedSize) is needed to produce meaningful results.

type ArrayValue 

type ArrayValue []Value

ArrayValue represents values of array type. Arrays of size zero are illegal.

func (ArrayValue) Type 

func (v ArrayValue) Type() Type

Type returns the type of the value. The returned type will always be an *ArrayType and it will have correctly populated Base, Size and ComputedSize fields.

type Ast 

type Ast struct {
	Decls []interface{}
}

Ast represents an abstract syntax tree of a parsed program. It is just a holder for a list of declarations.

type BareType 

type BareType struct {
	// contains filtered or unexported fields
}

func GetFundamentalType 

func GetFundamentalType(t BareType) BareType

GetFundamentalType returns the fundamental type of a given builtin type. E.g., the fundamental type of TVec2 is TFloat, since vec2 is a vector of two flots. For types which cannot be used in vectors or matrices (such as sampler types or void), the function returns TVoid as their fundamental type.

func GetMatrixType 

func GetMatrixType(col, row uint8) BareType

Returns a matrix type with the given number of columns and rows. In case the number of rows or columns is 1, returns a vector type. In case both are 1, returns TFloat.

func GetPrecisionType 

func GetPrecisionType(t BareType) (prect BareType, hasPrecision bool)

GetPrecisionType returns the type from which the provided type inherits is precision. E.g., vec2 inherits its type from float as they have the same basic type. If the type cannot be qualified with a precision the second result is false.

func GetVectorType 

func GetVectorType(fund BareType, size uint8) BareType

GetVectorType returns the builtin vector type with the given fundamental type (TFloat, TInt, TUint and TBool) and the given size. E.g., GetVectorType(TBool, 4) == TBvec4. In case size is 1 it returns the corresponding scalar type. It is illegal to call this function with any other type except the four types mentioned.

func (BareType) Canonicalize 

func (t BareType) Canonicalize() BareType

Canonicalize returns a canonical representation of the type. Specifically, it returns TMat2x2 instead of TMat2, etc.

func (BareType) String 

func (t BareType) String() string

type BinaryExpr 

type BinaryExpr struct {
	Left  Expression
	Op    BinaryOp
	Right Expression

	OpCst *parse.Leaf

	ExprType Type // Found by semantic analysis.
}

E_Left op E_Right

func (*BinaryExpr) Constant 

func (e *BinaryExpr) Constant() bool

func (*BinaryExpr) LValue 

func (e *BinaryExpr) LValue() bool

func (*BinaryExpr) Type 

func (e *BinaryExpr) Type() Type

type BinaryOp 

type BinaryOp struct {
	// contains filtered or unexported fields
}

A type for binary operators of the language.

func (BinaryOp) String 

func (op BinaryOp) String() string

type BoolValue 

type BoolValue bool

BoolValue represents a boolean value.

func (BoolValue) Type 

func (v BoolValue) Type() Type

type BreakStmt 

type BreakStmt struct {
	BreakCst     *parse.Leaf
	SemicolonCst *parse.Leaf
}

break;

type BuiltinFunction 

type BuiltinFunction struct {
	RetType Type
	SymName string
	Params  []*FuncParameterSym
	Impl    func(v []Value) Value
}

BuiltinFunction is the definition of a GLSL builtin function. It implements the Function interface. The definition of the function is provided as an opaque go function.

func (*BuiltinFunction) Constant 

func (f *BuiltinFunction) Constant() bool

func (*BuiltinFunction) LValue 

func (f *BuiltinFunction) LValue() bool

func (*BuiltinFunction) Name 

func (f *BuiltinFunction) Name() string

func (*BuiltinFunction) Parameters 

func (f *BuiltinFunction) Parameters() []*FuncParameterSym

func (*BuiltinFunction) ReturnType 

func (f *BuiltinFunction) ReturnType() Type

func (*BuiltinFunction) Type 

func (f *BuiltinFunction) Type() Type

type BuiltinType 

type BuiltinType struct {
	Precision Precision
	Type      BareType

	PrecisionCst *parse.Leaf
	TypeCst      *parse.Leaf
}

BuiltinType represents a builtin type of the language: int, float, vec2, etc. It also stores the precision of the type.

func (*BuiltinType) Equal 

func (bt *BuiltinType) Equal(other Type) bool

Two builtin types are equal if their Type members are equal. Precision is ignored.

type CallExpr 

type CallExpr struct {
	Callee Expression
	Args   []Expression

	LParenCst   *parse.Leaf
	CommaCst    []*parse.Leaf
	RParenCst   *parse.Leaf
	VoidPresent bool
	VoidCst     *parse.Leaf

	// Found by semantic analysis.
	ExprType     Type
	ExprConstant bool
}

Callee(Arg_1, ... Arg_n).

If the function is called with no arguments the VoidPresent field is set to indicate the usage of the f(void) call syntax.

func (*CallExpr) Constant 

func (e *CallExpr) Constant() bool

func (*CallExpr) LValue 

func (e *CallExpr) LValue() bool

func (*CallExpr) Type 

func (e *CallExpr) Type() Type

type CaseStmt 

type CaseStmt struct {
	Expr Expression

	CaseCst  *parse.Leaf
	ColonCst *parse.Leaf
}

case expr:

type ChildTransformer 

type ChildTransformer func(child, parent interface{}) interface{}

ChildTransformer is a callback function used by TransformChildren to visit nodes.

type ChildVisitor 

type ChildVisitor func(interface{})

ChildVisitor is a callback function used by VisitChildren to visit nodes.

type CompoundStmt 

type CompoundStmt struct {
	Stmts []interface{}

	LBraceCst *parse.Leaf
	RBraceCst *parse.Leaf
}

{ stmts... }

type ConditionalExpr 

type ConditionalExpr struct {
	Cond      Expression
	TrueExpr  Expression
	FalseExpr Expression

	QuestionCst *parse.Leaf
	ColonCst    *parse.Leaf
}

E_c ? E_t : E_f

func (*ConditionalExpr) Constant 

func (e *ConditionalExpr) Constant() bool

func (*ConditionalExpr) LValue 

func (e *ConditionalExpr) LValue() bool

func (*ConditionalExpr) Type 

func (e *ConditionalExpr) Type() Type

type ConstantExpr 

type ConstantExpr struct {
	Value Value

	ValCst *parse.Leaf
}

ConstantExpr holds integer, floating point and boolean constants.

func (*ConstantExpr) Constant 

func (e *ConstantExpr) Constant() bool

func (*ConstantExpr) LValue 

func (e *ConstantExpr) LValue() bool

func (*ConstantExpr) Type 

func (e *ConstantExpr) Type() Type

type ContinueStmt 

type ContinueStmt struct {
	ContinueCst  *parse.Leaf
	SemicolonCst *parse.Leaf
}

continue;

type DeclarationStmt 

type DeclarationStmt struct {
	Decl interface{}
}

DeclarationStmt is a statement holding a declaration.

type DefaultStmt 

type DefaultStmt struct {
	DefaultCst *parse.Leaf
	ColonCst   *parse.Leaf
}

default:

type DiscardStmt 

type DiscardStmt struct {
	DiscardCst   *parse.Leaf
	SemicolonCst *parse.Leaf
}

discard;

type DoStmt 

type DoStmt struct {
	Stmt interface{}
	Expr Expression

	DoCst        *parse.Leaf
	LParenCst    *parse.Leaf
	RParenCst    *parse.Leaf
	WhileCst     *parse.Leaf
	SemicolonCst *parse.Leaf
}

do stmt while(expr);

type DotExpr 

type DotExpr struct {
	Expr  Expression
	Field string

	DotCst   *parse.Leaf
	FieldCst *parse.Leaf

	// Found by semantic analysis.
	ExprType     Type
	ExprConstant bool
	ExprLValue   bool
}

E . field

This expression represents struct member selection (struct.member), vector swizzle (vec4.xyz) and array length (array.length) expressions.

func (*DotExpr) Constant 

func (e *DotExpr) Constant() bool

func (*DotExpr) LValue 

func (e *DotExpr) LValue() bool

func (*DotExpr) Type 

func (e *DotExpr) Type() Type

type EmptyStmt 

type EmptyStmt struct {
	SemicolonCst *parse.Leaf
}

;

type ErrorCollector 

type ErrorCollector []error

ErrorCollector is an object which collects parsing errors.

func (*ErrorCollector) Error 

func (e *ErrorCollector) Error(err ...error)

Error adds the arguments to the collection of errors.

func (*ErrorCollector) Errorf 

func (e *ErrorCollector) Errorf(message string, args ...interface{})

Errorf adds an error defined by a format string to the collector.

func (*ErrorCollector) GetErrors 

func (e *ErrorCollector) GetErrors() []error

GetErrors returns the collected errors.

type Expression 

type Expression interface {
	LValue() bool
	Type() Type
	Constant() bool
}

The interface for all expressions in the program. It defines methods retrieving the expression type, its const-ness, and lvalued-ness. These are to be called only after a semantic analysis pass over the program.

type ExpressionCond 

type ExpressionCond struct {
	Expr Expression
}

ExpressionCond is a condition holding an expression. Conditions are used in ForStmt and WhileStmt.

type ExpressionStmt 

type ExpressionStmt struct {
	Expr Expression

	SemicolonCst *parse.Leaf
}

ExpressionStmt is a statement holding an expression.

type FloatValue 

type FloatValue float64

FloatValue represents a floating point value, as a float64.

func (FloatValue) String 

func (v FloatValue) String() string

func (FloatValue) Type 

func (v FloatValue) Type() Type

type ForStmt 

type ForStmt struct {
	Init interface{} // statement
	Cond interface{} // condition
	Loop Expression
	Body interface{} // statement

	ForCst        *parse.Leaf
	LParenCst     *parse.Leaf
	Semicolon2Cst *parse.Leaf // semicolon1 is a part of Init
	RParenCst     *parse.Leaf
}

for(init; cond; loop) body

The second member Cond is expected to hold an expression (ExpressionCond) or a declaration of a single variable (VarDeclCond).

type FuncParameterSym 

type FuncParameterSym struct {
	Const     bool
	Direction ParamDirection
	SymType   Type
	SymName   string

	ConstCst      *parse.Leaf
	DirectionCst  *parse.Leaf
	NameCst       *parse.Leaf
	ArrayAfterVar bool // Whether the variable was declared as int foo[].
}

FuncParameter is a formal function parameter in a function declaration.

func (*FuncParameterSym) Constant 

func (v *FuncParameterSym) Constant() bool

func (*FuncParameterSym) LValue 

func (v *FuncParameterSym) LValue() bool

func (*FuncParameterSym) Name 

func (v *FuncParameterSym) Name() string

func (*FuncParameterSym) Type 

func (v *FuncParameterSym) Type() Type

type Function 

type Function interface {
	ValueSymbol
	ReturnType() Type
	Parameters() []*FuncParameterSym
}

Function is an interface for function declarations. In addition to ValueSymbol methods, it provides methods to retrieve function return type and function parameters.

type FunctionDecl 

type FunctionDecl struct {
	RetType Type
	SymName string
	Params  []*FuncParameterSym
	Stmts   *CompoundStmt

	NameCst      *parse.Leaf
	LParenCst    *parse.Leaf
	CommaCst     []*parse.Leaf
	RParenCst    *parse.Leaf
	SemicolonCst *parse.Leaf
	VoidPresent  bool
	VoidCst      *parse.Leaf
}

FunctionDecl is a function declaration in a GLSL program. If field Stsms is not nil, then it represents a function definition. FunctionDecl implements ValueSymbol and Function.

If the function is declared with no arguments the VoidPresent field is set to indicate the usage of the f(void) call syntax.

func (*FunctionDecl) Constant 

func (f *FunctionDecl) Constant() bool

func (*FunctionDecl) LValue 

func (f *FunctionDecl) LValue() bool

func (*FunctionDecl) Name 

func (f *FunctionDecl) Name() string

func (*FunctionDecl) Parameters 

func (f *FunctionDecl) Parameters() []*FuncParameterSym

func (*FunctionDecl) ReturnType 

func (f *FunctionDecl) ReturnType() Type

func (*FunctionDecl) Type 

func (f *FunctionDecl) Type() Type

type FunctionType 

type FunctionType struct {
	ArgTypes []Type
	RetType  Type
}

FunctionType represents function types. The GLES Shading Language does not specify the presence of function types, but we add it to be able to handle expressions uniformly. A function type can appear in the AST in the following manner:

- VarRefExpr to a function declaration,

- "array.length" expression,

- the "type" part of the "type(expression)" type constructor syntax.

In all valid programs a expression of a function type can be present only as a child of a call expression.

func (*FunctionType) Equal 

func (t *FunctionType) Equal(other Type) bool

Two function types are equal if they have the same return and argument types.

type FunctionValue 

type FunctionValue struct {
	Func    func(v []Value) Value
	ValType *FunctionType
}

func (FunctionValue) Type 

func (v FunctionValue) Type() Type

type IfStmt 

type IfStmt struct {
	IfExpr   Expression
	ThenStmt interface{}
	ElseStmt interface{}

	IfCst     *parse.Leaf
	LParenCst *parse.Leaf
	RParenCst *parse.Leaf
	ElseCst   *parse.Leaf
}

if(ifExpr) thenStmt else elseStmt

if ElseStms is nil, the statement has no else clause.

type IndexExpr 

type IndexExpr struct {
	Base  Expression
	Index Expression

	LBracketCst *parse.Leaf
	RBracketCst *parse.Leaf

	ExprType Type // Found by semantic analysis.
}

Base[Index]

func (*IndexExpr) Constant 

func (e *IndexExpr) Constant() bool

func (*IndexExpr) LValue 

func (e *IndexExpr) LValue() bool

func (*IndexExpr) Type 

func (e *IndexExpr) Type() Type

type IntValue 

type IntValue int32

IntValue represents an integer value, as a int32.

func (IntValue) String 

func (v IntValue) String() string

func (IntValue) Type 

func (v IntValue) Type() Type

type InterpolationQualifier 

type InterpolationQualifier uint8
const (
	IntNone InterpolationQualifier = iota
	IntSmooth
	IntFlat
)

func (InterpolationQualifier) String 

func (i InterpolationQualifier) String() string

type InvariantDecl 

type InvariantDecl struct {
	Vars []*VarRefExpr

	InvariantCst *parse.Leaf
	CommaCst     []*parse.Leaf
	SemicolonCst *parse.Leaf
}

invariant foo, bar, baz;

type Language 

type Language uint8
const (
	LangVertexShader   Language = iota // Vertex Shader language
	LangFragmentShader                 // Fragment Shader language
	LangPreprocessor                   // Language of the #if preprocessor expressions
)

Constants identifying various sub-languages.

type LayoutDecl 

type LayoutDecl struct {
	Layout *LayoutQualifier

	UniformCst   *parse.Leaf
	SemicolonCst *parse.Leaf
}

layout(...) uniform;

type LayoutQualifier 

type LayoutQualifier struct {
	Ids []LayoutQualifierID

	LayoutCst *parse.Leaf
	LParenCst *parse.Leaf
	CommaCst  []*parse.Leaf
	RParenCst *parse.Leaf
}

layout(...)

type LayoutQualifierID 

type LayoutQualifierID struct {
	Name  string
	Value Value

	NameCst  *parse.Leaf
	EqualCst *parse.Leaf
	ValueCst *parse.Leaf
}

A single name = value pair in the layout qualifier. If the qualifier is present just as a bare name (without the value) then Value is nil.

type MatrixValue 

type MatrixValue struct {
	Members [][]Value
	ValType BuiltinType
}

MatrixValue represents matrix. Its elements are stored column-major.

func NewMatrixValue 

func NewMatrixValue(t BareType, member func(col, row uint8) Value) MatrixValue

NewMatrixValue constructs a new matrix value. The number of colums and rows is determined using the type argument. The member callback function should return a value for each matrix member, given its column and row. The function is called in column-major order. The type of the created value will always be in a canonical (TMat2x2 instead of TMat2) form.

func NewMatrixValueCR 

func NewMatrixValueCR(col, row uint8, member func(col, row uint8) Value) MatrixValue

NewMatrixValueCR constructs a new matrix value, given the number of its columns and rows. It is possible (and occasionally useful) to create matrix values with invalid sizes (number of columns of rows equal to 1 or greater than 4), but then the ValType field will not be populated correctly. The function is called in column-major order. The type of the created value will always be in a canonical (TMat2x2 instead of TMat2) form.

func (MatrixValue) Type 

func (v MatrixValue) Type() Type

type MultiVarDecl 

type MultiVarDecl struct {
	Vars  []*VariableSym
	Quals *TypeQualifiers
	Type  Type

	FunnyComma    bool // for declarations like: `int ,a;`
	FunnyCommaCst *parse.Leaf
	CommaCst      []*parse.Leaf
	SemicolonCst  *parse.Leaf
}

MultiVarDecl is a declaration of a (possibly more than one) variable. If no qualifiers are present, the Quals field can be null.

type ParamDirection 

type ParamDirection uint8

The direction of a parameter in a function declaration. 

const (
	DirNone ParamDirection = iota
	DirIn
	DirOut
	DirInout
)

func (ParamDirection) String 

func (d ParamDirection) String() string

type ParenExpr 

type ParenExpr struct {
	Expr Expression

	LParenCst *parse.Leaf
	RParenCst *parse.Leaf
}

( E )

func (*ParenExpr) Constant 

func (e *ParenExpr) Constant() bool

func (*ParenExpr) LValue 

func (e *ParenExpr) LValue() bool

func (*ParenExpr) Type 

func (e *ParenExpr) Type() Type

type Precision 

type Precision uint8

Precision of a type 

const (
	NoneP Precision = iota
	LowP
	MediumP
	HighP
)

func (Precision) String 

func (p Precision) String() string

type PrecisionDecl 

type PrecisionDecl struct {
	Type *BuiltinType

	PrecisionCst *parse.Leaf
	SemicolonCst *parse.Leaf
}

precision lowp int;

type ReturnStmt 

type ReturnStmt struct {
	Expr Expression

	ReturnCst    *parse.Leaf
	SemicolonCst *parse.Leaf
}

return expr;

type StorageQualifier 

type StorageQualifier uint8
const (
	StorNone StorageQualifier = iota
	StorConst
	StorUniform
	StorIn
	StorOut
	StorCentroidIn
	StorCentroidOut
	StorAttribute
	StorVarying
)

func (StorageQualifier) String 

func (s StorageQualifier) String() string

type StructSym 

type StructSym struct {
	SymName string
	Vars    []*MultiVarDecl

	StructCst *parse.Leaf
	NameCst   *parse.Leaf
	LBraceCst *parse.Leaf
	RBraceCst *parse.Leaf
}

StructSym is the struct declaration. It has a name and a list of variable declarations.

func (*StructSym) Name 

func (s *StructSym) Name() string

type StructType 

type StructType struct {
	Sym       *StructSym
	StructDef bool // if true, the structure was defined at this point in the AST.

	NameCst *parse.Leaf // Only used if StructDef is false
}

StructType represents structure types as a pointer to the corresponding structure symbol.

func (*StructType) Equal 

func (s *StructType) Equal(other Type) bool

type StructValue 

type StructValue struct {
	Members map[string]Value
	ValType *StructType
}

StructValue represents values of structure types.

func NewStructValue 

func NewStructValue(t *StructType, member func(name string) Value) StructValue

NewStructValue construct a new struct value, given its type and a callback function. The function should return the value for a member, given its name.

func (StructValue) Type 

func (v StructValue) Type() Type

type SwitchStmt 

type SwitchStmt struct {
	Expr  Expression
	Stmts *CompoundStmt

	SwitchCst *parse.Leaf
	LParenCst *parse.Leaf
	RParenCst *parse.Leaf
}

switch(expr) stmts

type Symbol 

type Symbol interface {
	Name() string
}

Symbol is an interface for all declared symbols (anything that has a name and is scoped) in the language. It does not always coincide with the "declaration" concept. E.g.: 'int a,b;' is a single declaration, but declares two symbols; the declaration 'struct A { ... } a;' declares one symbol for the struct and another for the variable, etc.

type Type 

type Type interface {
	// Whether two objects represent the same type, according to the language semantics.
	Equal(other Type) bool
}

Type represents a language type along with its precision.

type TypeConversionExpr 

type TypeConversionExpr struct {
	RetType Type

	ArgTypes []Type // Found by semantic analysis.
}

TypeConversionExpr represents a type conversion expression. It is only used as the "callee" child of CallExpr. The RetType member is the type specified in the program (the type we are converting to). The ArgTypes member is computed by semantic analysis from the arguments. The full type of the expression (what Type() returns) is then a FunctionType{RetType, ArgTypes}.

func (*TypeConversionExpr) Constant 

func (e *TypeConversionExpr) Constant() bool

func (*TypeConversionExpr) LValue 

func (e *TypeConversionExpr) LValue() bool

func (*TypeConversionExpr) Type 

func (e *TypeConversionExpr) Type() Type

type TypeQualifiers 

type TypeQualifiers struct {
	Invariant     bool
	Interpolation InterpolationQualifier
	Layout        *LayoutQualifier
	Storage       StorageQualifier

	InvariantCst       *parse.Leaf
	InterpolationCst   *parse.Leaf
	CentroidStorageCst *parse.Leaf
	StorageCst         *parse.Leaf
}

Invariant, interpolation, layout and storage qualifiers of declared variables.

type UintValue 

type UintValue uint32

UintValue represents an unsigned integer value, as a uint32.

func (UintValue) String 

func (v UintValue) String() string

func (UintValue) Type 

func (v UintValue) Type() Type

type UnaryExpr 

type UnaryExpr struct {
	Op   UnaryOp
	Expr Expression

	OpCst *parse.Leaf
}

UnaryExpr represents both prefix and postfix unary operators.

func (*UnaryExpr) Constant 

func (e *UnaryExpr) Constant() bool

func (*UnaryExpr) LValue 

func (e *UnaryExpr) LValue() bool

func (*UnaryExpr) Type 

func (e *UnaryExpr) Type() Type

type UnaryOp 

type UnaryOp BinaryOp

A type for unary operators of the language.

func GetPrefixOp 

func GetPrefixOp(opname string) (op UnaryOp, present bool)

GetPrefixOp returns the prefix unary operator associated with the given string. For "++" it returns UoPreinc instead of UoPostinc. If an operator is not found, the second result is false.

func (UnaryOp) String 

func (o UnaryOp) String() string

type UniformBlock 

type UniformBlock struct {
	Layout  *LayoutQualifier
	SymName string
	Vars    []*MultiVarDecl

	UniformCst *parse.Leaf
	NameCst    *parse.Leaf
	LBraceCst  *parse.Leaf
	RBraceCst  *parse.Leaf
}

UniformBlock represents the "block" part of the uniform interface declarations. 

layout(...) uniform BlockName { int Var; ... } InstanceName;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
               UniformBlock
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                       UniformDecl

Implements Symbol with Name = BlockName.

func (*UniformBlock) Name 

func (u *UniformBlock) Name() string

type UniformDecl 

type UniformDecl struct {
	Block   *UniformBlock
	SymName string
	Size    Expression

	NameCst      *parse.Leaf
	LBracketCst  *parse.Leaf
	RBracketCst  *parse.Leaf
	SemicolonCst *parse.Leaf
}

UniformDecl represents a whole uniform interface declaration. 

layout(...) uniform BlockName { int Var; ... } InstanceName;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
               UniformBlock
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                       UniformDecl

Implements Symbol with Name = InstanceName.

func (*UniformDecl) Name 

func (u *UniformDecl) Name() string

type Value 

type Value interface {
	Type() Type
}

A langauge value. Each value has a type.

type ValueSymbol 

type ValueSymbol interface {
	Symbol
	Type() Type
	LValue() bool
	Constant() bool
}

ValueSymbol represents a Symbol (a named object in the language), which can be used in a value context in the language (basically, referenced in an expression through VarRefExpr). After a semantic analysis pass the three functions provide information about the nature of the symbol.

type VarDeclCond 

type VarDeclCond struct {
	Sym *VariableSym
}

VarDeclCond is a condition holding a declaration of a single variable. Conditions are used in ForStmt and WhileStmt.

type VarRefExpr 

type VarRefExpr struct {
	Sym ValueSymbol

	SymCst *parse.Leaf
}

VarRefExpr represents a reference to a declared symbol used in an expression.

func (*VarRefExpr) Constant 

func (e *VarRefExpr) Constant() bool

func (*VarRefExpr) LValue 

func (e *VarRefExpr) LValue() bool

func (*VarRefExpr) Type 

func (e *VarRefExpr) Type() Type

type VariableSym 

type VariableSym struct {
	SymType Type
	SymName string
	Init    Expression

	Quals *TypeQualifiers

	NameCst  *parse.Leaf
	EqualCst *parse.Leaf

	SymLValue bool // Found by semantic analysis.
}

VariableSym is a declaration of a single variable, possibly with an initialization expression. It is normally a part of a MultiVarDecl (for normal declaration) or a VarDeclCond (for declarations which are a part of while and for statements).

func (*VariableSym) Constant 

func (v *VariableSym) Constant() bool

func (*VariableSym) LValue 

func (v *VariableSym) LValue() bool

func (*VariableSym) Name 

func (v *VariableSym) Name() string

func (*VariableSym) Type 

func (v *VariableSym) Type() Type

type VectorComponentKind 

type VectorComponentKind uint8

VectorComponentKind is a type representing various ways of addressing vector components. 

const (
	ComponentKindNone VectorComponentKind = iota
	ComponentKindXYZW
	ComponentKindRGBA
	ComponentKindSTPQ
)

Constants representing ways of adressing vector components.

func GetVectorComponentInfo 

func GetVectorComponentInfo(r rune) (position uint8, kind VectorComponentKind)

GetVectorComponentInfo returns information about a rune, when used as a vector swizzle character. It returns the VectorComponentKind this rune belongs to (or ComponentKindNone if it is an invalid rune) and the vector position this rune refers to. The position indexes are 0-based.

type VectorValue 

type VectorValue struct {
	Members []Value
	ValType BuiltinType
}

VectorValue represents vector values.

func NewVectorValue 

func NewVectorValue(t BareType, member func(i uint8) Value) VectorValue

NewVectorValue constructs a new vector value, given its type and a member callback function. The number of elements is determined from the type. The member function should return the member value, given its id. It is called in the natural order.

func (VectorValue) Type 

func (v VectorValue) Type() Type

type WhileStmt 

type WhileStmt struct {
	Cond interface{}
	Stmt interface{}

	WhileCst  *parse.Leaf
	LParenCst *parse.Leaf
	RParenCst *parse.Leaf
}

while(cond) stmt

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