> >> $_ # current topic
> >> $__ # outer topic
> >> $___ # outer outer topic
>
> [not sufficiently visibly distinct]
> [too much anyway]
Agreed.
Returning to the topic of binding/copying
from a caller to a callee, what about using
square brackets to mark implicit args thus:
sub bar ($a, $b)
[$_, $foo]
{ ... }
In the above, implicit args go inside the
square brackets and the topic and $foo of
the sub being def'd are the same as (aliased
to) the topic and $foo of the calling sub.
As I said before, if you call a sub you
really ought to know that sub's signature,
and the above would make it clear that $_
and $foo are shared between caller and callee.
Of course, you might then come back and
change your calling code, accidentally
clobbering a shared lexical. So, back at
the caller end of things, I suggest the
following (simplified from an earlier post):
o There's a property that controls whether
called subs can share a given lexical of
a callee. I'll call this property Yours.
o By default, topics are set to Yours(rw);
other lexicals are set to not Yours.
--
ralph
