In objective -c you can use [self class] to get the Class of an object. From there you can get the NSBundle. A smart man can use a macro when locating strings and make one such that [self class] is used to get the correct bundle. However, swift does not have macros. Below is a work around that does something similar.

implicitBundle.swift

import Foundation
/**
original macro

#define DHLocalizedString(KEY, TABLE, COMMENT) NSLocalizedStringWithDefaultValue(KEY, TABLE, [NSBundle mainBundle], NSLocalizedStringWithDefaultValue(KEY, TABLE, [NSBundle bundleForClass:[self class]]), COMMENT)
*/


func getNameByRemovingPrefixPathAndExtension(name: String) -> String {
	let url = NSURL(string: name)!
	let className = url.URLByDeletingPathExtension!.lastPathComponent!
	return className
}
func objectifySwiftSelector(sel: String) -> Selector {
	return NSSelectorFromString(sel.componentsSeparatedByCharactersInSet(NSCharacterSet(charactersInString: "()_")).reduce("", combine: +))
}
func objectifySwiftSelector(sel: Selector) -> Selector {
	return objectifySwiftSelector(NSStringFromSelector(sel))
}
public func DHLocalizedStringFromTable(key: String, table: String, comment: String?, file: String = #file, funcName: String = #function) -> String {
	let className = getNameByRemovingPrefixPathAndExtension(file)
	for fw in NSBundle.allFrameworks() {
		let frameworkName = getNameByRemovingPrefixPathAndExtension(fw.bundlePath)
		print("\(frameworkName).\(className)")
		guard let cls = NSClassFromString("\(frameworkName).\(className)") else {
			continue
		}
		print(cls)
		let cls2 = (cls as! NSObject.Type).init()
		guard cls2.respondsToSelector(objectifySwiftSelector(funcName)) else {
			continue
		}
		// class found and function that called it is a part of that class
		let bundleOfClass = NSBundle(forClass: cls)
		let frameworkLocalizedString = NSLocalizedString(key, tableName: table, bundle: bundleOfClass, value: key, comment: comment ?? "")
		return NSLocalizedString(key, tableName: table, bundle: NSBundle.mainBundle(), value: frameworkLocalizedString, comment: comment ?? "")
	}
	return key
}