Swift – func deepDescription(any: Any) -> String (pretty print any object, recursively)

Swift – func deepDescription

func deepDescription(_ any: Any) -> String {
    guard let any = deepUnwrap(any) else {
        return "nil"
    }
    
    if any is Void {
        return "Void"
    }
    
    if let int = any as? Int {
        return String(int)
    } else if let double = any as? Double {
        return String(double)
    } else if let float = any as? Float {
        return String(float)
    } else if let bool = any as? Bool {
        return String(bool)
    } else if let string = any as? String {
        return "\"\(string)\""
    }
    
    let indentedString: (String) -> String = {
        $0.components(separatedBy: .newlines).map {
            $0.isEmpty ? "" : "\r    \($0)" }.joined(separator: "")
    }
    
    let mirror = Mirror(reflecting: any)
    
    let properties = Array(mirror.children)
    
    guard let displayStyle = mirror.displayStyle else {
        return String(describing: any)
    }
    
    switch displayStyle {
    case .tuple:
        if properties.count == 0 { return "()" }
        
        var string = "("
        
        for (index, property) in properties.enumerated() {
            if property.label!.first! == "." {
                string += deepDescription(property.value)
            } else {
                string += "\(property.label!): \(deepDescription(property.value))"
            }
            
            string += (index < properties.count - 1 ? ", " : "")
        }
        
        return string + ")"
    case .collection, .set:
        if properties.count == 0 { return "[]" }
        
        var string = "["
        
        for (index, property) in properties.enumerated() {
            string += indentedString(deepDescription(property.value) + (index < properties.count - 1 ? ",\r" : ""))
        }
        
        return string + "\r]"
    case .dictionary:
        if properties.count == 0 { return "[:]" }
        
        var string = "["
        
        for (index, property) in properties.enumerated() {
            let pair = Array(Mirror(reflecting: property.value).children)
            
            string += indentedString("\(deepDescription(pair[0].value)): \(deepDescription(pair[1].value))" + (index < properties.count - 1 ? ",\r" : ""))
        }
        
        return string + "\r]"
    case .enum:
        if let any = any as? CustomDebugStringConvertible {
            return any.debugDescription
        }
        
        if properties.count == 0 { return "\(mirror.subjectType)." + String(describing: any) }
        
        var string = "\(mirror.subjectType).\(properties.first!.label!)"
        
        let associatedValueString = deepDescription(properties.first!.value)
        
        if associatedValueString.first! == "(" {
            string += associatedValueString
        } else {
            string += "(\(associatedValueString))"
        }
        
        return string
    case .struct, .class:
        if let any = any as? CustomDebugStringConvertible {
            return any.debugDescription
        }
        
        if properties.count == 0 { return String(describing: any) }
        
        var string = "<\(mirror.subjectType)"
        
        if displayStyle == .class {
            string += ": \(Unmanaged<AnyObject>.passUnretained(any as AnyObject).toOpaque())"
        }
        
        string += "> {"
        
        for (index, property) in properties.enumerated() {
            string += indentedString("\(property.label!): \(deepDescription(property.value))" + (index < properties.count - 1 ? ",\r" : ""))
        }
        
        return string + "\r}"
    case .optional: fatalError("deepUnwrap must have failed...")
    }
}

func deepUnwrap(_ any: Any) -> Any? {
    let mirror = Mirror(reflecting: any)
    
    if mirror.displayStyle != .optional {
        return any
    }
    
    if let child = mirror.children.first, child.label == "Some" {
        return deepUnwrap(child.value)
    }
    
    return nil
}