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Postings from August 2000
Damian Conway:
> My forthcoming proposal will be that invocants still be passed as $_[0]
> by default, but that there be a pragma allowing $_[0] to be automagically
> shifted somewhere else during dispatch. For example:
>
>
> sub method { print "I was called through: $_[0]";
> print "My args were: @_[1..$#_]"; } #default
> use invocant '$ME';
> sub method { print "I was called through: $ME";
> print "My args were: @_"; }
Why couldn't(/shouldn't/wouldn't) this be more useful as a facility that
allows you to define a chunk of code that gets inserted in each sub routine?
I'm not sure what the general facility would look like, but it seems to me
like the "use invocant '<variable>'" pragma is just essentially sticking a:
my <variable> = shift ;
as the first line in each method... wouldn't it be more fun to let people do
something like:
use invocation 'my $ME = shift; print "I was called through : $ME" ;
print "My args were : @_" ;'
... which, of course, means that duplicating the method above is as simple
as:
sub method { # use invocation stuff gets shoved in here
}
(Or, was it already intended that the implementation of 'use invocant' might
be some sort of compile-time macro?)
Dirk