Hashable's StaticString

static.swift

import Foundation

extension StaticString: Equatable {

    public static func == (lhs: StaticString, rhs: StaticString) -> Bool {
        let lp = UnsafeRawPointer(lhs.utf8Start).assumingMemoryBound(to: Int8.self)
        let rp = UnsafeRawPointer(rhs.utf8Start).assumingMemoryBound(to: Int8.self)
        return strcmp(lp, rp) == 0
    }

}

extension StaticString: Hashable {

    public func hash(into hasher: inout Hasher) {
        hasher.combine(bytes: UnsafeRawBufferPointer(start: utf8Start, count: utf8CodeUnitCount))
    }

}

var dictionary: [StaticString: Int] = [:]

dictionary["Swift"] = 42

Just noting the above StaticString comparison will blow up if the StaticString is a unicode scalar. A safer method that also works with scalars is ...

    public static func == (lhs: Self, rhs: Self) -> Bool {
        if lhs.hasPointerRepresentation && rhs.hasPointerRepresentation {
            if lhs.utf8Start == rhs.utf8Start {
                return true
            }            
            return strcmp(lhs.utf8Start, rhs.utf8Start) == 0
        } else if lhs.asPointerRepresentation == false && rhs.hasPointerRepresentation == false {
            return lhs.unicodeScalar.value == rhs.unicodeScalar.value
        }
        // in this context if one's a scalar and one's a pointer unequal
        return false
    }