Struct ProductType

pub struct ProductType {
    pub elements: Box<[ProductTypeElement]>,
}

A structural product type of the factors given by elements.

This is also known as struct and tuple in many languages, but note that unlike most languages, products in SATs are structural and not nominal. When checking whether two nominal types are the same, their names and/or declaration sites (e.g., module / namespace) are considered. Meanwhile, a structural type system would only check the structure of the type itself, e.g., the names of its fields and their types in the case of a record. The name “product” comes from category theory.

See also:

• https://en.wikipedia.org/wiki/Record_(computer_science)
• https://ncatlab.org/nlab/show/product+type

These structures are known as product types because the number of possible values in product

{ N_0: T_0, N_1: T_1, ..., N_n: T_n }

is:

Π (i ∈ 0..n). values(T_i)

so for example, values({ A: U64, B: Bool }) = values(U64) * values(Bool).

Fields

elements: Box<[ProductTypeElement]>

The factors of the product type.

These factors can either be named or unnamed. When all the factors are unnamed, we can regard this as a plain tuple type.

Implementations

impl ProductType

pub fn decode<'a>( bytes: &mut impl BufReader<'a>, ) -> Result<ProductType, DecodeError>

pub fn encode(&self, bytes: &mut impl BufWriter)

impl ProductType

pub const fn new(elements: Box<[ProductTypeElement]>) -> ProductType

Returns a product type with the given elements as its factors.

pub fn unit() -> ProductType

Returns the unit product type.

pub fn is_identity(&self) -> bool

Returns whether this is the special case of spacetimedb_lib::Identity. Does not follow Refs.

pub fn is_connection_id(&self) -> bool

Returns whether this is the special case of spacetimedb_lib::ConnectionId. Does not follow Refs.

pub fn is_timestamp(&self) -> bool

Returns whether this is the special case of spacetimedb_lib::Timestamp. Does not follow Refs.

pub fn is_time_duration(&self) -> bool

Returns whether this is the special case of spacetimedb_lib::TimeDuration. Does not follow Refs.

pub fn is_identity_tag(tag_name: &str) -> bool

Returns whether this is the special tag of Identity.

pub fn is_connection_id_tag(tag_name: &str) -> bool

Returns whether this is the special tag of ConnectionId.

pub fn is_timestamp_tag(tag_name: &str) -> bool

Returns whether this is the special tag of crate::timestamp::Timestamp.

pub fn is_time_duration_tag(tag_name: &str) -> bool

Returns whether this is the special tag of crate::time_duration::TimeDuration.

pub fn is_special_tag(tag_name: &str) -> bool

Returns whether this is a special known tag, currently Address, Identity, Timestamp or TimeDuration.

pub fn is_special(&self) -> bool

Returns whether this is a special known type, currently ConnectionId or Identity. Does not follow Refs.

pub fn is_unit(&self) -> bool

Returns whether this is a unit type, that is, has no elements.

pub fn index_of_field_name(&self, name: &str) -> Option<usize>

Returns index of the field with the given name.

pub fn project( &self, cols: &ColList, ) -> Result<AlgebraicType, InvalidFieldError>

This utility function is designed to project fields based on the supplied indexes.

Important:

The resulting AlgebraicType will wrap into a ProductType when projecting multiple (including zero) fields, otherwise it will consist of a single AlgebraicType.

Parameters:

• cols: A ColList containing the indexes of fields to be projected.

impl ProductType

pub fn as_value(&self) -> AlgebraicValue

pub fn from_value( value: &AlgebraicValue, ) -> Result<ProductType, ValueDeserializeError>

Trait Implementations

impl Clone for ProductType

fn clone(&self) -> ProductType

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ProductType

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ProductType

fn deserialize<D>( deserializer: D, ) -> Result<ProductType, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given deserializer.

impl<'de> Deserialize<'de> for ProductType

fn deserialize<D>( deserializer: D, ) -> Result<ProductType, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<const N: usize> From<[(&str, AlgebraicType); N]> for ProductType

fn from(fields: [(&str, AlgebraicType); N]) -> ProductType

Converts to this type from the input type.

impl<const N: usize> From<[(Option<&str>, AlgebraicType); N]> for ProductType

fn from(fields: [(Option<&str>, AlgebraicType); N]) -> ProductType

Converts to this type from the input type.

impl<const N: usize> From<[AlgebraicType; N]> for ProductType

fn from(fields: [AlgebraicType; N]) -> ProductType

Converts to this type from the input type.

impl<const N: usize> From<[ProductTypeElement; N]> for ProductType

fn from(fields: [ProductTypeElement; N]) -> ProductType

Converts to this type from the input type.

impl From<AlgebraicType> for ProductType

fn from(x: AlgebraicType) -> ProductType

Converts to this type from the input type.

impl From<Box<[ProductTypeElement]>> for ProductType

fn from(fields: Box<[ProductTypeElement]>) -> ProductType

Converts to this type from the input type.

impl From<ProductType> for AlgebraicType

fn from(original: ProductType) -> AlgebraicType

Converts to this type from the input type.

impl<'a, I> FromIterator<(&'a str, I)> for ProductType

where I: Into<AlgebraicType>,

fn from_iter<T>(iter: T) -> ProductType

where T: IntoIterator<Item = (&'a str, I)>,

Creates a value from an iterator.

impl<'a, I> FromIterator<(Option<&'a str>, I)> for ProductType

where I: Into<AlgebraicType>,

fn from_iter<T>(iter: T) -> ProductType

where T: IntoIterator<Item = (Option<&'a str>, I)>,

Creates a value from an iterator.

impl<I> FromIterator<I> for ProductType

where I: Into<ProductTypeElement>,

fn from_iter<T>(iter: T) -> ProductType

where T: IntoIterator<Item = I>,

Creates a value from an iterator.

impl Hash for ProductType

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 MetaType for ProductType

fn meta_type() -> AlgebraicType

Returns the type structure of this type as an AlgebraicType.

impl Ord for ProductType

fn cmp(&self, other: &ProductType) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for ProductType

fn eq(&self, other: &ProductType) -> 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 ProductType

fn partial_cmp(&self, other: &ProductType) -> 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 Serialize for ProductType

fn serialize<S>( &self, __serializer: S, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize self in the data format of S using the provided serializer.

impl Serialize for ProductType

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

where S: Serializer,

Serialize this value into the given Serde serializer.

impl SpacetimeType for ProductType

fn make_type<S>(__typespace: &mut S) -> AlgebraicType

where S: TypespaceBuilder,

Returns an AlgebraicType representing the type for Self in SATS and in the typing context in typespace. This is used by the automatic type registration system in Rust modules.

impl Eq for ProductType

impl StructuralPartialEq for ProductType