Trait budvm::DynamicValue

pub trait DynamicValue: Send + Sync + Debug + 'static {
    // Required methods
    fn is_truthy(&self) -> bool;
    fn kind(&self) -> Symbol;

    // Provided methods
    fn as_i64(&self) -> Option<i64> { ... }
    fn convert(&self, kind: &Symbol) -> Option<Value> { ... }
    fn partial_eq(&self, other: &Value) -> Option<bool> { ... }
    fn partial_cmp(&self, other: &Value) -> Option<Ordering> { ... }
    fn checked_add(
        &self,
        other: &Value,
        is_reverse: bool
    ) -> Result<Option<Value>, FaultKind> { ... }
    fn checked_sub(
        &self,
        other: &Value,
        is_reverse: bool
    ) -> Result<Option<Value>, FaultKind> { ... }
    fn checked_mul(
        &self,
        other: &Value,
        is_reverse: bool
    ) -> Result<Option<Value>, FaultKind> { ... }
    fn checked_div(
        &self,
        other: &Value,
        is_reverse: bool
    ) -> Result<Option<Value>, FaultKind> { ... }
    fn call(
        &self,
        name: &Symbol,
        args: &mut PoppedValues<'_>
    ) -> Result<Value, FaultKind> { ... }
    fn to_source(&self) -> Option<String> { ... }
    fn hash<H>(&self, state: &mut H) -> bool
       where H: Hasher { ... }
}

A type that can be used in the virtual machine using Value::dynamic.

Required Methods

fn is_truthy(&self) -> bool

Returns true if the value contained is truthy. See Value::is_truthy() for examples of what this means for primitive types.

fn kind(&self) -> Symbol

Returns a unique string identifying this type. This returned string will be wrapped in ValueKind::Dynamic when Value::kind() is invoked on a dynamic value.

This value does not influence the virtual machine’s behavior. The virtual machine uses this string only when creating error messages.

Provided Methods

fn as_i64(&self) -> Option<i64>

Returns this value as an i64, if possible.

Implementhing this function enables this type to be used in integer operations such as bitwise operations.

fn convert(&self, kind: &Symbol) -> Option<Value>

Converts this value to the given kind, if possible.

If this function returns None, the virtual machine will return a fault from the conversion operation.

fn partial_eq(&self, other: &Value) -> Option<bool>

Returns true if self and other are considered equal. Returns false if self and other are able to be compared but are not equal. Returns None if the values are unable to be compared.

When evaluating left = right with dynamic values, if left.partial_eq(right) returns None, right.partial_eq(left) will be attempted before returning false.

fn partial_cmp(&self, other: &Value) -> Option<Ordering>

Returns the relative ordering of self and other, if a comparison is able to be made. If the types cannot be compared, this function should return None.

When evaluating a comparison such as left < right with dynamic values, if left.partial_cmp(right) returns None, right.partial_cmp(left).map(Ordering::reverse) will be attempted before returning false.

fn checked_add( &self, other: &Value, is_reverse: bool ) -> Result<Option<Value>, FaultKind>

Attempts to compute the result adding self and other.

While addition is normally an associative operation, is_reverse allows determining if self is the left operand or the right operand to the operation.

If is_reverse is false, the operation being requested is self + other. If is_reverse is true, the operation being requested is other + self.

fn checked_sub( &self, other: &Value, is_reverse: bool ) -> Result<Option<Value>, FaultKind>

Attempts to compute the result subtracting self and other.

If is_reverse is false, the operation being requested is self - other. If is_reverse is true, the operation being requested is other - self.

fn checked_mul( &self, other: &Value, is_reverse: bool ) -> Result<Option<Value>, FaultKind>

Attempts to compute the result multiplying self and other.

While multiplication is normally an associative operation, is_reverse allows determining if self is the left operand or the right operand to the operation.

If is_reverse is false, the operation being requested is self * other. If is_reverse is true, the operation being requested is other * self.

fn checked_div( &self, other: &Value, is_reverse: bool ) -> Result<Option<Value>, FaultKind>

Attempts to compute the result dividing self and other.

If is_reverse is false, the operation being requested is self / other. If is_reverse is true, the operation being requested is other / self.

fn call( &self, name: &Symbol, args: &mut PoppedValues<'_> ) -> Result<Value, FaultKind>

Calls a function by name with args.

fn to_source(&self) -> Option<String>

Returns this value as represented in source, if possible.

fn hash<H>(&self, state: &mut H) -> boolwhere H: Hasher,

Hashes the contents of this value. Returns true if this operation is supported.

To allow the Value type to implement Hash but contain values that don’t implement Hash, this is not a trait that is required to implement.

This allows safe collection types to be written, which check before key insertion that the value can be hashed and returns an error rather than panicking in the call to hash.

Implementations on Foreign Types

impl DynamicValue for String

fn is_truthy(&self) -> bool

fn kind(&self) -> Symbol

fn partial_eq(&self, other: &Value) -> Option<bool>

fn partial_cmp(&self, other: &Value) -> Option<Ordering>

fn call( &self, name: &Symbol, args: &mut PoppedValues<'_> ) -> Result<Value, FaultKind>

fn to_source(&self) -> Option<String>

fn checked_add( &self, other: &Value, _is_reverse: bool ) -> Result<Option<Value>, FaultKind>

fn checked_mul( &self, other: &Value, _is_reverse: bool ) -> Result<Option<Value>, FaultKind>

fn hash<H>(&self, state: &mut H) -> boolwhere H: Hasher,

Implementors

impl DynamicValue for List

impl<State> DynamicValue for HashMap<State>where State: BuildHasher + Debug + Clone + Send + Sync + 'static,