path: root/src/qml/jsapi/qjsprimitivevalue.cpp

// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qjsprimitivevalue.h"

#include <QtQml/private/qv4runtime_p.h>

QT_BEGIN_NAMESPACE

/*!
  \since 6.1
  \class QJSPrimitiveUndefined

  \inmodule QtQml

  \brief An empty marker type to signify the JavaScript Undefined type and its single value.
  \inmodule QtQml
 */

/*!
  \since 6.1
  \class QJSPrimitiveNull

  \inmodule QtQml

  \brief An empty marker type to signify the JavaScript null value.
  \inmodule QtQml
 */

/*!
  \since 6.1
  \class QJSPrimitiveValue

  \brief The QJSPrimitiveValue class operates on primitive types in JavaScript semantics.

  \ingroup qtjavascript
  \inmodule QtQml

  QJSPrimitiveValue supports most of the primitive types defined in the
  \l{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.
 */

/*!
  \enum QJSPrimitiveValue::Type

  This enum speicifies the types a QJSPrimitiveValue might contain.

  \value Undefined The JavaScript Undefined value.
  \value 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.
  \value Boolean A JavaScript Boolean value.
  \value Integer An integer. This is a special case of the JavaScript Number
                 type. JavaScript does not have an actual integer type, but
                 the \l{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.
  \value Double A JavaScript Number value.
  \value String A JavaScript String value.
 */

/*!
  \fn Type QJSPrimitiveValue::type() const

  Returns the type of the QJSPrimitiveValue.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue()

  Creates a QJSPrimitiveValue of type Undefined.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(QJSPrimitiveUndefined undefined)

  Creates a QJSPrimitiveValue of value \a undefined and type Undefined.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(QJSPrimitiveNull null)

  Creates a QJSPrimitiveValue of value \a null and type Null.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(bool value)

  Creates a QJSPrimitiveValue of value \a value and type Boolean.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(int value)

  Creates a QJSPrimitiveValue of value \a value and type Integer.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(double value)

  Creates a QJSPrimitiveValue of value \a value and type Double.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(QString value)

  Creates a QJSPrimitiveValue of value \a value and type String.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(QMetaType type, const void *value)
  \since 6.4

  Creates a QJSPrimitiveValue of type \a type, and initializes with
  \a value if \a type can be stored in QJSPrimtiveValue. \a value must not
  be nullptr in that case. If \a 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.
 */

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(QMetaType type)
  \since 6.6
  \internal

  Creates a QJSPrimitiveValue of type \a type, and initializes with a
  default-constructed value if \a type can be stored in QJSPrimtiveValue.
  If \a type cannot be stored this results in a QJSPrimitiveValue of type
  Undefined.
*/

/*!
  \fn QJSPrimitiveValue::QJSPrimitiveValue(const QVariant &value)

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

/*!
  \fn bool QJSPrimitiveValue::toBoolean() const

  Returns the value coerced a boolean by JavaScript rules.
 */

/*!
  \fn int QJSPrimitiveValue::toInteger() const

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

/*!
  \fn double QJSPrimitiveValue::toDouble() const

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

/*!
  \fn QString QJSPrimitiveValue::toString() const

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

/*!
  \fn QJSPrimitiveValue QJSPrimitiveValue::operator+(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)

  \since 6.1

  Perfoms the JavaScript '+' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn QJSPrimitiveValue QJSPrimitiveValue::operator-(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '-' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn QJSPrimitiveValue QJSPrimitiveValue::operator*(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '*' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn QJSPrimitiveValue QJSPrimitiveValue::operator/(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '/' operation between \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn bool QJSPrimitiveValue::strictlyEquals(const QJSPrimitiveValue &other) const

  Performs the JavaScript '===' operation on this QJSPrimitiveValue and
  \a other, and returns the result.
 */

/*!
  \fn bool QJSPrimitiveValue::equals(const QJSPrimitiveValue &other) const

  Performs the JavaScript '==' operation on this QJSPrimitiveValue and
  \a other, and returns the result.
 */

/*!
  \fn bool QJSPrimitiveValue::operator==(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '===' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn bool QJSPrimitiveValue::operator!=(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '!==' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn bool QJSPrimitiveValue::operator<(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '<' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn bool QJSPrimitiveValue::operator>(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '>' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn bool QJSPrimitiveValue::operator<=(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '<=' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn bool QJSPrimitiveValue::operator>=(const QJSPrimitiveValue &lhs, const QJSPrimitiveValue &rhs)
  \since 6.1

  Performs the JavaScript '>=' operation on \a lhs and \a rhs, and returns the
  result.
 */

/*!
  \fn QMetaType QJSPrimitiveValue::metaType() const
  \since 6.6

  Returns the QMetaType of the value stored in the QJSPrimitiveValue.
 */

/*!
  \fn const void *QJSPrimitiveValue::constData() const
  \fn const void *QJSPrimitiveValue::data() const
  \since 6.6

  Returns a pointer to the contained value as a generic void* that cannot be
  written to.
 */

/*!
  \fn const void *QJSPrimitiveValue::data()
  \since 6.6

  Returns a pointer to the contained data as a generic void* that can be
  written to.
*/

/*!
  \fn template<QJSPrimitiveValue::Type type> QJSPrimitiveValue QJSPrimitiveValue::to() const
  \since 6.6

  Coerces the value to the specified \e type and returns the result as a new
  QJSPrimitiveValue.

  \sa toBoolean(), toInteger(), toDouble(), toString()
*/

QString QJSPrimitiveValue::toString(double d)
{
    QString result;
    QV4::RuntimeHelpers::numberToString(&result, d);
    return result;
}

/*!
  \fn double QQmlPrivate::jsExponentiate(double base, double exponent)
  \internal
  \since 6.4

  Performs JavaScript's Number::exponentiate operation on \a base and
  \a exponent, and returns the result.

  See https://tc39.es/ecma262/multipage/ecmascript-data-types-and-values.html#sec-numeric-types-number-exponentiate
 */

QT_END_NAMESPACE