GenericRequirement

GenericRequirement

A generic requirement.

public struct GenericRequirement:​ Hashable, Codable

A generic type or function declaration may specifying one or more requirements in a generic where clause before the opening curly brace ({) its body. Each generic requirement establishes a relation between two type identifiers.

For example, the following declaration specifies two generic requirements:​

func difference<C1:​ Collection, C2:​ Collection>(between lhs:​ C1, and rhs:​ C2) -> [C1.Element]
   where C1.Element:​ Equatable, C1.Element == C2.Element

• The first generic requirement establishes a conformance relation between the generic types identified by "C1.Element" and "Equatable"

• The second generic requirement establsihes a sameType relation between the generic types identified by "C1.Element" and "C2.Element"

Inheritance

Codable, CustomStringConvertible, Hashable

Properties

relation

The relation between the two identified types.

let relation:​ Relation

leftTypeIdentifier

The identifier for the left-hand side type.

let leftTypeIdentifier:​ String

rightTypeIdentifier

The identifier for the right-hand side type.

let rightTypeIdentifier:​ String

description

var description:​ String

Methods

genericRequirements(from:​)

Creates and returns generic requirements initialized from a generic requirement list syntax node.

public static func genericRequirements(from node:​ GenericRequirementListSyntax?) -> [GenericRequirement]

Parameters

• from:​ - from:​ The generic requirement list syntax node, or nil.

Returns

An array of generic requirements, or nil if the node is nil.