VTable

vortex_array::expr::functions

Trait VTable 

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pub trait VTable:
    'static
    + Send
    + Sync
    + Sized {
    type Options: 'static + Send + Sync + Clone + PartialEq + Eq + Hash + Debug + Display;

    // Required methods
    fn id(&self) -> FunctionId;
    fn arity(&self, options: &Self::Options) -> Arity;
    fn arg_name(&self, options: &Self::Options, arg_idx: usize) -> ArgName;
    fn return_dtype(
        &self,
        options: &Self::Options,
        arg_types: &[DType],
    ) -> VortexResult<DType>;
    fn execute(
        &self,
        _options: &Self::Options,
        _args: &ExecutionArgs,
    ) -> VortexResult<Datum>;

    // Provided methods
    fn serialize(
        &self,
        _options: &Self::Options,
    ) -> VortexResult<Option<Vec<u8>>> { ... }
    fn deserialize(&self, _bytes: &[u8]) -> VortexResult<Self::Options> { ... }
    fn null_handling(&self, options: &Self::Options) -> NullHandling { ... }
    fn stat_falsification(
        &self,
        options: &Self::Options,
        expr: &Expression,
        catalog: &dyn StatsCatalog,
    ) -> Option<Expression> { ... }
    fn stat_expression(
        &self,
        options: &Self::Options,
        expr: &Expression,
        stat: Stat,
        catalog: &dyn StatsCatalog,
    ) -> Option<Expression> { ... }
}
Expand description

A non-object-safe vtable trait for scalar function types.

This trait should be implemented in order to define new scalar functions within Vortex.

Required Associated Types§

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type Options: 'static + Send + Sync + Clone + PartialEq + Eq + Hash + Debug + Display

Any options for configuring the function’s behaviour.

Required Methods§

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fn id(&self) -> FunctionId

The globally unique identifier for this function.

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fn arity(&self, options: &Self::Options) -> Arity

Returns the arity (number of arguments) for this function.

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fn arg_name(&self, options: &Self::Options, arg_idx: usize) -> ArgName

Returns the display name of the nth argument for this function.

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fn return_dtype( &self, options: &Self::Options, arg_types: &[DType], ) -> VortexResult<DType>

Computes the return DType given the argument types and function options.

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fn execute( &self, _options: &Self::Options, _args: &ExecutionArgs, ) -> VortexResult<Datum>

Binds the function for execution over a specific set of inputs.

Provided Methods§

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fn serialize(&self, _options: &Self::Options) -> VortexResult<Option<Vec<u8>>>

Serializes the options for a function instance.

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fn deserialize(&self, _bytes: &[u8]) -> VortexResult<Self::Options>

Deserializes the options for this function from a byte slice.

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fn null_handling(&self, options: &Self::Options) -> NullHandling

How the function behaves when one or more arguments are NULL.

Most functions propagate NULL (any NULL argument produces NULL output). Some functions have special NULL handling that can short-circuit evaluation or treat NULL as a meaningful value.

Required for correct NULL semantics; may also enable optimizations when argument nullability is known from schema or statistics.

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fn stat_falsification( &self, options: &Self::Options, expr: &Expression, catalog: &dyn StatsCatalog, ) -> Option<Expression>

See Expression::stat_falsification

Note that the falsification API will change in the future to instead use a falsify expression along with push-down rules.

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fn stat_expression( &self, options: &Self::Options, expr: &Expression, stat: Stat, catalog: &dyn StatsCatalog, ) -> Option<Expression>

See Expression::stat_expression

Note that the stat_expression API will change in the future such that layouts with pruning capabilities perform their own mapping over statistics.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§