I have always felt that the compiler/interpreter should give as much information as possible when it finds a syntax error. Nothing is more irritating than just getting a "Syntax error somewhere in your script". Therefore I think 4a and 4e are bad, because they are equvialent to a rude RTFM. A PerlMonk might, and in some cases should, say RTFM when a too simple question is asked, because answering the same thing over and over again is tiring. A compiler/interpreter/syntax checker never get's tired. In my opinion, 4c and 4b are excellent.