Trait ketos::value::ForeignValue [−] [src]

pub trait ForeignValue: AnyValue + Debug {
    fn is_equal_to(&self, rhs: &ForeignValue) -> Result<bool, ExecError>;
    fn type_name(&self) -> &'static str;

    fn compare_to(&self, _rhs: &ForeignValue) -> Result<Ordering, ExecError> { ... }
    fn compare_to_value(&self, rhs: &Value) -> Result<Ordering, ExecError> { ... }
    fn is_identical_to(&self, rhs: &ForeignValue) -> bool { ... }
    fn is_equal_to_value(&self, rhs: &Value) -> Result<bool, ExecError> { ... }
    fn fmt_debug(&self, _names: &NameStore, f: &mut Formatter) -> Result { ... }
    fn fmt_display(&self, names: &NameStore, f: &mut Formatter) -> Result { ... }
    fn is_type(&self, name: &str) -> bool { ... }
    fn call_value(&self, _scope: &Scope, _args: &mut [Value]) -> Result<Value, Error> { ... }
}

Represents a type of value defined outside the core interpreter.

Required Methods

fn is_equal_to(&self, rhs: &ForeignValue) -> Result<bool, ExecError>

Tests for equality between two values of a foreign type.

fn type_name(&self) -> &'static str

Return the value's type name.

Provided Methods

fn compare_to(&self, _rhs: &ForeignValue) -> Result<Ordering, ExecError>

Performs ordered comparison between two values of a foreign type.

If a true, Ord-like comparison cannot be made, ExecError::CannotCompare(..) should be returned.

The default implementation unconditionally returns an error.

fn compare_to_value(&self, rhs: &Value) -> Result<Ordering, ExecError>

Performs ordered comparison between two values.

This method need only be implemented if a value of the foreign type may be compared with core value types.

fn is_identical_to(&self, rhs: &ForeignValue) -> bool

Returns whether the two values are identical. This concept is the same as equality, except in the case of floating point values, where two NaN values are considered identical.

A type implementing ForeignValue need only implement is_identical if it contains a float-type value or emulates some equality relationship similar to NaN.

fn is_equal_to_value(&self, rhs: &Value) -> Result<bool, ExecError>

Tests for equality between two values.

This method need only be implemented if a value of the foreign type may be compared with core value types.

fn fmt_debug(&self, _names: &NameStore, f: &mut Formatter) -> Result

Format the value in debugging mode.

The default implementation uses the type's fmt::Debug representation.

fn fmt_display(&self, names: &NameStore, f: &mut Formatter) -> Result

Format the value in display mode.

The default implementation formats the value in debugging mode.

fn is_type(&self, name: &str) -> bool

Returns whether this value is of the named type.

The default implementation checks against the value of self.type_name().

fn call_value(&self, _scope: &Scope, _args: &mut [Value]) -> Result<Value, Error>

Calls the value as a function.

The default implementation unconditionally returns an error.

Methods

impl ForeignValue
[src]

fn is<T: Any>(&self) -> bool

Returns whether the contained value is of the given type.

fn downcast_ref<T: Any>(&self) -> Option<&T>

Returns a reference to the contained value, if it is of the given type.

fn downcast_mut<T: Any>(&mut self) -> Option<&mut T>

Returns a mutable reference to the contained value, if it is of the given type.

Implementors