[% setvar title Request For New Pragma: Implicit %]
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Request For New Pragma: Implicit
Maintainer: Bryan C. Warnock <email@example.com> Date: 5 Aug 2000 Last Modified: 28 Aug 2000 Mailing List: firstname.lastname@example.org Number: 2 Version: 3 Status: Frozen
Perl 6 should add a new pragma called
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.
?. It just
rolled off the fingers.
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
? "Print me.!".
But I digress.
There should be an
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 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.
Or, 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.
Laziness, pure and simple.
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
no implicit arg, the front-end would have to not assume
the implicit $_ as an argument.
I've no real concrete ideas on this, sorry.
use implicitand the sematics it would add. (Obviously, other changes to the language notwithstanding.)
no implicit would put it on the user. After all, he doesn't have to
;print the contents of $_ to the default filehandle? ;-)
RFC 40: Module Scope Control.
Frozen as is. Most people don't like it. I don't like it. Not really. I hate to think that Perl will have more pragmas than functions at the current pace.
But I like the idea behind it. I think a smarter solution would be found in something akin to "RFC 40". In which case, I would gladly withdraw it.