Often it is inconvenient and opaque entering string literals that are in tended as regex patterns into a swift source.
Taking the lead from python it perhaps a new syntax r"\w+\s+\w" could be added to the swift language. This would be equivalent to "\\w+\\s+
w". The specification required would be that if a string literal is preceded by r then unknown escapes are passed though to the literal as-is including the back-slash character rather than going an error. This would be a very minor change confined to Lexer.cpp that I'll work on tomorrow and present to swift-evolution.