This and other RFCs are available on the web at http://tmtowtdi.perl.org/rfc/ =head1 TITLE Request For New Pragma: Implicit =head1 VERSION Maintainer: Bryan C. Warnock <[EMAIL PROTECTED]> Date: 5 Aug 2000 Version: 2 Mailing List: [EMAIL PROTECTED] Number: 41 =head1 ABSTRACT Perl 6 should add a new pragma called C<implicit>. =head1 DESCRIPTION I am lazy. I am spoiled by the implicit $_. I like the implicit $_. Implicit $_ good. Ugh. (Conversely, some people abhor the implicit $_ while in a strict programming environment, as it tends to add confusion.) I came to the sysadm / programming world in a long, circuitous route. I never programmed with toggle switches. I've never seen a punch card. My first programming was in Commodore 64 Basic. C64 Basic. No safe-signals there, either. ;) It did have one good thing, though. One very useful thing, for lazy people like me. C<print> could be written like C<?>. It just rolled off the fingers. C<10 ?"Port Perl for the 64!">. Of course, those days have gone. I've seen the light. I'm a *nix head and JAPH. But how I still hate typing out print. Particularly because I do it so much. Oh, sure, I could play games with HERE docs and the ilk, but I'm too lazy. (Like I posted in a response, I wrangled an input filter to allow me to write C<? "Print me.!". But I digress. There should be an C<implicit> pragma that gives new life and meaning to void context constructs. In my case, I want it to print to the default filehandle, (which is also implicit, I might add.) Scoping needs to be tightly controlled, of course. Don't want someone else's void context to show up on your display, now do you? And, of course, it would be defaulted to off. It could continue to ignore constant 0s and 1s. (But those pre-pod embedded comment strings just B<have> to go.) Ideally, I'd like to use it for printing, but I suppose some other lazy person may want to use it for something else. Like, from reading the traffic, to prevent laziness. One of the suggestions was to disallow implicit $_ for functions. That could fit right in with this pragma. It would be on be default, but you could turn it off. =head1 MOTIVATORS Laziness, pure and simple. =head1 IMPLEMENTATION The front-end would have to detect void usage and either arrange to have the results passed to a callback, (in which case, would you know what wantarray() wants to know?) or inject the appropriate term in the optree. In the case of C<no implicit arg>, the front-end would have to not assume the implicit $_ as an argument. =head2 SUMMARY OF IMPLEMENTATION I've no real concrete ideas on this, sorry. =head2 IMPACT =over 4 =item * Impact on Perl 5. Mutual compatibility between Perl 5 and Perl 6, with the exception of C<use implicit> and the sematics it would add. (Obviously, other changes to the language notwithstanding.) =back =head2 UNKNOWNS =over 4 =item * What about subs? Backticks? Things that return meaningless printable information, like system()? C<no implicit> would put it on the user. After all, he doesn't have to use it. =item * Would C<;> print the contents of $_ to the default filehandle? ;-) =back =head1 REFERENCES Upcoming RFC on module scoping.
