Struct Signature

pub struct Signature {
    pub type_signature: TypeSignature,
    pub volatility: Volatility,
}

Defines the supported argument types (TypeSignature) and Volatility for a function.

DataFusion will automatically coerce (cast) argument types to one of the supported function signatures, if possible.

Fields

type_signature: TypeSignature

The data types that the function accepts. See TypeSignature for more information.

volatility: Volatility

The volatility of the function. See Volatility for more information.

Implementations

impl Signature

pub fn new(type_signature: TypeSignature, volatility: Volatility) -> Signature

Creates a new Signature from a given type signature and volatility.

pub fn variadic( common_types: Vec<DataType>, volatility: Volatility, ) -> Signature

An arbitrary number of arguments with the same type, from those listed in common_types.

pub fn user_defined(volatility: Volatility) -> Signature

User-defined coercion rules for the function.

pub fn numeric(arg_count: usize, volatility: Volatility) -> Signature

A specified number of numeric arguments

pub fn string(arg_count: usize, volatility: Volatility) -> Signature

A specified number of numeric arguments

pub fn variadic_any(volatility: Volatility) -> Signature

An arbitrary number of arguments of any type.

pub fn uniform( arg_count: usize, valid_types: Vec<DataType>, volatility: Volatility, ) -> Signature

A fixed number of arguments of the same type, from those listed in valid_types.

pub fn exact(exact_types: Vec<DataType>, volatility: Volatility) -> Signature

Exactly matches the types in exact_types, in order.

pub fn coercible( target_types: Vec<Coercion>, volatility: Volatility, ) -> Signature

Target coerce types in order

pub fn comparable(arg_count: usize, volatility: Volatility) -> Signature

Used for function that expects comparable data types, it will try to coerced all the types into single final one.

pub fn nullary(volatility: Volatility) -> Signature

pub fn any(arg_count: usize, volatility: Volatility) -> Signature

A specified number of arguments of any type

pub fn one_of( type_signatures: Vec<TypeSignature>, volatility: Volatility, ) -> Signature

Any one of a list of TypeSignatures.

pub fn array_and_element(volatility: Volatility) -> Signature

Specialized Signature for ArrayAppend and similar functions

pub fn array_and_element_and_optional_index(volatility: Volatility) -> Signature

Specialized Signature for Array functions with an optional index

pub fn array_and_index(volatility: Volatility) -> Signature

Specialized Signature for ArrayElement and similar functions

pub fn array(volatility: Volatility) -> Signature

Specialized Signature for ArrayEmpty and similar functions

Trait Implementations

impl Clone for Signature

fn clone(&self) -> Signature

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Signature

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Hash for Signature

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Signature

fn eq(&self, other: &Signature) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Signature

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

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for Signature

impl StructuralPartialEq for Signature