General purpose to make a concrete Error instance in Swift

Error.swift

//
//	ZError.swift
//	ZKit
//
//	Created by Kaz Yoshikawa on 7/18/22.
//
//	Usage:
//	General usage for throwing Error in Swift language.
//
//	Example:
//	guard let number = number else { throw ZError("number should not be nil.") }

import Foundation

struct ZError: Error, CustomStringConvertible {
	let message: String
	let fileID: String
	let function: String
	let line: Int
	init(_ message: String, fileID: String = #fileID, function: String = #function, line: Int = #line) {
		self.message = message
		self.fileID = fileID
		self.function = function
		self.line = line
	}
	var description: String {
		return "\(message): \(fileID), \(function)(\(line)"
	}
}