perl.org wrote:
> On Wed, 14 Jul 2004 15:45:52 -0400, Bob Showalter wrote
> > perl.org wrote:
> > >
> > > I still don't understand the reasoning for this - how could adding
> > > more to the sub signature be worse than not having any?
> >
> > This is explained in perldoc perlsub.
>
> What section are you referring to?
This section:
It's probably best to prototype new functions, not retrofit
prototyping
into older ones. That's because you must be especially careful about
silent impositions of differing list versus scalar contexts. For
exam-
ple, if you decide that a function should take just one parameter,
like
this:
sub func ($) {
my $n = shift;
print "you gave me $n\n";
}
and someone has been calling it with an array or expression returning
a
list:
func(@foo);
func( split /:/ );
Then you've just supplied an automatic "scalar" in front of their
argu-
ment, which can be more than a bit surprising. The old "@foo" which
used to hold one thing doesn't get passed in. Instead, "func()" now
gets passed in a "1"; that is, the number of elements in "@foo". And
the "split" gets called in scalar context so it starts scribbling on
your "@_" parameter list. Ouch!
Follow Randal's advice if you don't like mine :~)
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