Trait BaseValue 

pub trait BaseValue:
    Clone
    + Hash
    + Eq
    + Any
    + Debug
    + Send
    + Sync {
    const MAY_UNBOX: bool = false;

    // Provided methods
    fn intern(&self, table: &InternTable<Self, Value>) -> Value { ... }
    fn as_any(&self) -> &dyn Any { ... }
    fn try_box(&self) -> Option<Value> { ... }
    fn try_unbox(_val: Value) -> Option<Self> { ... }
}

A simple data type that can be interned in a database.

Most callers can simply implement this trait on their desired type, with no overrides needed. For types that are particularly small, users can override BaseValue::try_box and BaseValue::try_unbox methods and set BaseValue::MAY_UNBOX to true to allow the Rust value to be stored in-place in a Value.

Regardless, all base value types should be registered in a BaseValues instance using the BaseValues::register_type method before they can be used in the database.

Provided Associated Constants

const MAY_UNBOX: bool = false

Provided Methods

fn intern(&self, table: &InternTable<Self, Value>) -> Value

fn as_any(&self) -> &dyn Any

fn try_box(&self) -> Option<Value>

fn try_unbox(_val: Value) -> Option<Self>

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl BaseValue for &'static str

impl BaseValue for ()

fn try_unbox(_val: Value) -> Option<Self>

To optimize storage, we map Value 0 to unit type.

use egglog_core_relations::BaseValue;
let unit_value = ().try_box().unwrap();
assert_eq!(<()>::try_unbox(unit_value).unwrap(), ());

const MAY_UNBOX: bool = true

fn try_box(&self) -> Option<Value>

impl BaseValue for Rational64

impl BaseValue for String

impl BaseValue for bool

fn try_unbox(val: Value) -> Option<Self>

see bool::try_box

fn try_box(&self) -> Option<Value>

To optimize storage, we map Value 1 to true and 0 to false in the implementation. As an example, the subsumed column of a table has type bool.

use egglog_core_relations::BaseValue;
let true_value = true.try_box().unwrap();
let false_value = false.try_box().unwrap();
assert_eq!(bool::try_unbox(true_value).unwrap(), true);
assert_eq!(bool::try_unbox(false_value).unwrap(), false);

const MAY_UNBOX: bool = true

impl BaseValue for i8

const MAY_UNBOX: bool = true

fn try_unbox(val: Value) -> Option<Self>

fn try_box(&self) -> Option<Value>

impl BaseValue for i16

const MAY_UNBOX: bool = true

fn try_unbox(val: Value) -> Option<Self>

fn try_box(&self) -> Option<Value>

impl BaseValue for i32

const MAY_UNBOX: bool = true

fn try_unbox(val: Value) -> Option<Self>

fn try_box(&self) -> Option<Value>

impl BaseValue for i64

const MAY_UNBOX: bool = true

fn try_box(&self) -> Option<Value>

fn try_unbox(val: Value) -> Option<Self>

impl BaseValue for isize

const MAY_UNBOX: bool = true

fn try_box(&self) -> Option<Value>

fn try_unbox(val: Value) -> Option<Self>

impl BaseValue for u8

const MAY_UNBOX: bool = true

fn try_unbox(val: Value) -> Option<Self>

fn try_box(&self) -> Option<Value>

impl BaseValue for u16

const MAY_UNBOX: bool = true

fn try_unbox(val: Value) -> Option<Self>

fn try_box(&self) -> Option<Value>

impl BaseValue for u32

const MAY_UNBOX: bool = true

fn try_unbox(val: Value) -> Option<Self>

fn try_box(&self) -> Option<Value>

impl BaseValue for u64

const MAY_UNBOX: bool = true

fn try_box(&self) -> Option<Value>

fn try_unbox(val: Value) -> Option<Self>

impl BaseValue for usize

const MAY_UNBOX: bool = true

fn try_box(&self) -> Option<Value>

fn try_unbox(val: Value) -> Option<Self>

Implementors

impl<T: Hash + Eq + Debug + Clone + Send + Sync + 'static> BaseValue for Boxed<T>