Class Value¶

Defined in File slint-interpreter.h

Class Documentation¶

class Value¶

This is a dynamically typed value used in the Slint interpreter. It can hold a value of different types, and you should use the different overloaded constructors and the to_xxx() functions to access the value within.

It is also possible to query the type the value holds by calling the Value::type() function.

Note that models are only represented in one direction: You can create a slint::Model<Value> in C++, store it in a std::shared_ptr and construct Value from it. Then you can set it on a property in your .slint code that was declared to be either an array (property <[sometype]> foo;) or an object literal (property <{foo: string, bar: int}> my_prop;). Such properties are dynamic and accept models implemented in C++.

Value v(42.0); // Creates a value that holds a double with the value 42.

Value some_value = ...;
// Check if the value has a string
if (std::optional<slint::SharedString> string_value = some_value.to_string())
    do_something(*string_value);  // Extract the string by de-referencing

Public Types

using Type = ValueType ¶: A convenience alias for the value type enum.

Public Functions

inline Value()¶: Constructs a new value of type Value::Type::Void.

inline Value(const Value &other)¶: Constructs a new value by copying other.

inline Value(Value &&other)¶: Constructs a new value by moving other to this.

inline Value &operator=(const Value &other)¶: Assigns the value other to this.

inline Value &operator=(Value &&other)¶: Moves the value other to this.

inline ~Value()¶: Destroys the value.

inline std::optional<double> to_number() const¶: Returns a std::optional that contains a double if the type of this Value is Type::Double, otherwise an empty optional is returned.

inline std::optional<slint::SharedString> to_string() const¶: Returns a std::optional that contains a string if the type of this Value is Type::String, otherwise an empty optional is returned.

inline std::optional<bool> to_bool() const¶: Returns a std::optional that contains a bool if the type of this Value is Type::Bool, otherwise an empty optional is returned.

inline std::optional<slint::SharedVector<Value>> to_array() const¶

Returns a std::optional that contains a vector of values if the type of this Value is Type::Model, otherwise an empty optional is returned.

The vector will be constructed by serializing all the elements of the model.

inline std::optional<slint::Brush> to_brush() const¶: Returns a std::optional that contains a brush if the type of this Value is Type::Brush, otherwise an empty optional is returned.

inline std::optional<Struct> to_struct() const¶: Returns a std::optional that contains a Struct if the type of this Value is Type::Struct, otherwise an empty optional is returned.

inline std::optional<Image> to_image() const¶: Returns a std::optional that contains an Image if the type of this Value is Type::Image, otherwise an empty optional is returned.

inline Value(double value)¶: Constructs a new Value that holds the double value.

inline Value(int value)¶: Constructs a new Value that holds the int value. Internally this is stored as a double and Value::type() will return Value::Type::Number.

inline Value(const SharedString &str)¶: Constructs a new Value that holds the string str.

inline Value(bool b)¶: Constructs a new Value that holds the boolean b.

inline Value(const SharedVector<Value> &v)¶: Constructs a new Value that holds the value vector v as a model.

inline Value(const std::shared_ptr<slint::Model<Value>> &m)¶: Constructs a new Value that holds the value model m.

inline Value(const slint::Brush &brush)¶: Constructs a new Value that holds the brush b.

inline Value(const Struct &struc)¶: Constructs a new Value that holds the Struct struc.

inline Value(const Image &img)¶: Constructs a new Value that holds the Image img.

inline Type type() const¶: Returns the type the variant holds.

Friends

inline friend bool operator==(const Value &a, const Value &b)¶: Returns true if a and b hold values of the same type and the underlying vales are equal.