Trait CustomValue

pub trait CustomValue:
    Debug
    + Send
    + Sync
    + Serialize
    + Deserialize {
    // Required methods
    fn clone_value(&self, span: Span) -> Value;
    fn type_name(&self) -> String;
    fn to_base_value(&self, span: Span) -> Result<Value, ShellError>;
    fn as_any(&self) -> &dyn Any;
    fn as_mut_any(&mut self) -> &mut dyn Any;

    // Provided methods
    fn follow_path_int(
        &self,
        self_span: Span,
        index: usize,
        path_span: Span,
    ) -> Result<Value, ShellError> { ... }
    fn follow_path_string(
        &self,
        self_span: Span,
        column_name: String,
        path_span: Span,
    ) -> Result<Value, ShellError> { ... }
    fn partial_cmp(&self, _other: &Value) -> Option<Ordering> { ... }
    fn operation(
        &self,
        lhs_span: Span,
        operator: Operator,
        op: Span,
        right: &Value,
    ) -> Result<Value, ShellError> { ... }
    fn notify_plugin_on_drop(&self) -> bool { ... }
}

Trait definition for a custom Value type

Required Methods

fn clone_value(&self, span: Span) -> Value

Custom Clone implementation

This can reemit a Value::CustomValue(Self, span) or materialize another representation if necessary.

fn type_name(&self) -> String

The friendly type name to show for the custom value, e.g. in describe and in error messages. This does not have to be the same as the name of the struct or enum, but conventionally often is.

fn to_base_value(&self, span: Span) -> Result<Value, ShellError>

Converts the custom value to a base nushell value.

This imposes the requirement that you can represent the custom value in some form using the Value representations that already exist in nushell

fn as_any(&self) -> &dyn Any

Any representation used to downcast object to its original type

fn as_mut_any(&mut self) -> &mut dyn Any

Any representation used to downcast object to its original type (mutable reference)

Provided Methods

fn follow_path_int( &self, self_span: Span, index: usize, path_span: Span, ) -> Result<Value, ShellError>

Follow cell path by numeric index (e.g. rows)

fn follow_path_string( &self, self_span: Span, column_name: String, path_span: Span, ) -> Result<Value, ShellError>

Follow cell path by string key (e.g. columns)

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

ordering with other value (see std::cmp::PartialOrd)

fn operation( &self, lhs_span: Span, operator: Operator, op: Span, right: &Value, ) -> Result<Value, ShellError>

Definition of an operation between the object that implements the trait and another Value.

The Operator enum is used to indicate the expected operation.

Default impl raises ShellError::UnsupportedOperator.

fn notify_plugin_on_drop(&self) -> bool

For custom values in plugins: return true here if you would like to be notified when all copies of this custom value are dropped in the engine.

The notification will take place via custom_value_dropped() on the plugin type.

The default is false.

Trait Implementations

impl<'typetag> Serialize for dyn CustomValue + 'typetag

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<'typetag> Serialize for dyn CustomValue + Send + 'typetag

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<'typetag> Serialize for dyn CustomValue + Send + Sync + 'typetag

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<'typetag> Serialize for dyn CustomValue + Sync + 'typetag

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

Implementors