Example code for emoji-fueled logs with type safety

log_with_emojis_and_types.swift

// A logging function that uses emojis to make the output prettier
// - one clear way to specify the type of display we want
// - provide type safety for the printed parameter
// - no weird operator syntax ;-)

// Inspired by "Swift: Pretty in print()" by Andyy Hope
// part 1: https://medium.com/p/64832bb7fafa/
// part 2: https://medium.com/p/640cea920653/

// Note: Ideally you would give the object to print first, so the completion
// can give the valid display modes available for that type. But I don't think
// there is any simple way to do that.

// This one is private, so the name is of no importance
// Don't forget to set a DEBUG CFlag, so it's all optimized away in production
private func __log<T>(type:String,_ input:T) {
	//#if DEBUG
	print(type,input)
	//#endif
}

// Use the parameter's tag to indicate the type of log
// Use the type to guarantee type safety as appropriate

// Everything about a type of logging is on a single line, making it easy to add one
// - write the type name only once
// - write the emoji on the same line
// - possibility to use the same type name with multiple types

// By the way, we don't want to clash with the math "log" function in auto complete
// so, let's add some letter that makes it easy for XCode

func llog(ln input: String) { __log("✏",input) }
func llog(url input: String) { __log("🌏",input) }
func llog(error input: NSError) { __log("❗",input) }
func llog(any input: Any) { __log("⚪",input) }
func llog(obj input: AnyObject) { __log("◽",input) }
func llog(date input: NSDate) { __log("🕒",input) }

// here we even specify how to print a url:
func llog(url input: NSURL) { __log("🌏",input.absoluteString) }

// Now here are some examples

import Foundation

let aString = "This is a string"
let url = "http://www.somewhere.com"
let nsurl = NSURL(string: url)!
let date = NSDate()
let error = NSError(domain: "A bad thing happened", code: 101, userInfo: nil)

llog(ln   : aString)
llog(url  : url)
llog(url  : nsurl)
llog(date : date)
llog(any  : ["Key":1337])
llog(error: error)