class QJSPrimitiveValue

The QJSPrimitiveValue class operates on primitive types in JavaScript semantics. More

Synopsis

Methods

Note

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Detailed Description

QJSPrimitiveValue supports most of the primitive types defined in the ECMA-262 standard, in particular Undefined, Boolean, Number, and String. Additionally, you can store a JavaScript null in a QJSPrimitiveValue and as a special case of Number, you can store an integer value.

All those values are stored immediately, without interacting with the JavaScript heap. Therefore, you can pass QJSPrimitiveValues between different JavaScript engines. In contrast to QJSManagedValue , there is also no danger in destroying a QJSPrimitiveValue from a different thread than it was created in. On the flip side, QJSPrimitiveValue does not hold a reference to any JavaScript engine.

QJSPrimitiveValue implements the JavaScript arithmetic and comparison operators on the supported types in JavaScript semantics. Types are coerced like the JavaScript engine would coerce them if the operators were written in a JavaScript expression.

The JavaScript Symbol type is not supported as it is of very limited utility regarding arithmetic and comparison operators, the main purpose of QJSPrimitiveValue . In particular, it causes an exception whenever you try to coerce it to a number or a string, and we cannot throw exceptions without a JavaScript Engine.

class Type

This enum speicifies the types a QJSPrimitiveValue might contain.

Constant

Description

QJSPrimitiveValue.Undefined

The JavaScript Undefined value.

QJSPrimitiveValue.Null

The JavaScript null value. This is in fact not a separate JavaScript type but a special value of the Object type. As it is very common and storable without JavaScript engine, it is still supported.

QJSPrimitiveValue.Boolean

A JavaScript Boolean value.

QJSPrimitiveValue.Integer

An integer. This is a special case of the JavaScript Number type. JavaScript does not have an actual integer type, but the ECMA-262 standard contains rules on how to transform a Number in order to prepare it for certain operators that only make sense on integers, in particular the bit shift operators. QJSPrimitiveValue ‘s Integer type represents the result of such a transformation.

QJSPrimitiveValue.Double

A JavaScript Number value.

QJSPrimitiveValue.String

A JavaScript String value.

__init__()

Creates a QJSPrimitiveValue of type Undefined.

__init__(type)
Parameters:

typeQMetaType

__init__(string)
Parameters:

string – str

Creates a QJSPrimitiveValue of value value and type String.

__init__(value)
Parameters:

value – bool

Creates a QJSPrimitiveValue of value value and type Boolean.

__init__(variant)
Parameters:

variant – object

Creates a QJSPrimitiveValue from the contents of value if those contents can be stored in QJSPrimtiveValue. Otherwise this results in a QJSPrimitiveValue of type Undefined.

__init__(value)
Parameters:

value – float

Creates a QJSPrimitiveValue of value value and type Double.

__init__(value)
Parameters:

value – int

Creates a QJSPrimitiveValue of value value and type Integer.

__init__(type, value)
Parameters:

Creates a QJSPrimitiveValue of type type, and initializes with value if type can be stored in QJSPrimtiveValue. value must not be nullptr in that case. If type cannot be stored this results in a QJSPrimitiveValue of type Undefined.

Note that you have to pass the address of the variable you want stored.

Usually, you never have to use this constructor, use the one taking QVariant instead.

constData()
Return type:

void

data()
Return type:

void

equals(other)
Parameters:

otherQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘==’ operation on this QJSPrimitiveValue and other, and returns the result.

metaType()
Return type:

QMetaType

Returns the QMetaType of the value stored in the QJSPrimitiveValue .

__ne__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘!==’ operation on lhs and rhs, and returns the result.

__mod__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

QJSPrimitiveValue

__mul__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

QJSPrimitiveValue

Performs the JavaScript ‘*’ operation on lhs and rhs, and returns the result.

__add__()
Return type:

QJSPrimitiveValue

__add__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

QJSPrimitiveValue

Perfoms the JavaScript ‘+’ operation on lhs and rhs, and returns the result.

__iadd__()
Return type:

QJSPrimitiveValue

__iadd__(arg__1)
Parameters:

arg__1 – int

Return type:

QJSPrimitiveValue

__sub__()
Return type:

QJSPrimitiveValue

__sub__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

QJSPrimitiveValue

Performs the JavaScript ‘-’ operation on lhs and rhs, and returns the result.

__isub__()
Return type:

QJSPrimitiveValue

__isub__(arg__1)
Parameters:

arg__1 – int

Return type:

QJSPrimitiveValue

__div__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

QJSPrimitiveValue

Performs the JavaScript ‘/’ operation between lhs and rhs, and returns the result.

__lt__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘<’ operation on lhs and rhs, and returns the result.

__le__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘<=’ operation on lhs and rhs, and returns the result.

__eq__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘===’ operation on lhs and rhs, and returns the result.

__gt__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘>’ operation on lhs and rhs, and returns the result.

__ge__(rhs)
Parameters:

rhsQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘>=’ operation on lhs and rhs, and returns the result.

strictlyEquals(other)
Parameters:

otherQJSPrimitiveValue

Return type:

bool

Performs the JavaScript ‘===’ operation on this QJSPrimitiveValue and other, and returns the result.

toBoolean()
Return type:

bool

Returns the value coerced a boolean by JavaScript rules.

toDouble()
Return type:

float

Returns the value coerced to a JavaScript Number by JavaScript rules.

toInteger()
Return type:

int

Returns the value coerced to an integral 32bit number by the rules JavaScript would apply when preparing it for a bit shift operation.

toString()
Return type:

str

Returns the value coerced to a JavaScript String by JavaScript rules.

toVariant()
Return type:

object

type()
Return type:

Type

Returns the type of the QJSPrimitiveValue .