Mark J. Reed wrote:
[I] wrote:
So I'd vote for going with simple semantics that are easy to explain --
that is, don't attempt implicit junctional collapse. Provide operators to
collapse when needed, but don't attempt to be too clever.
While it's easier to find clever programmers than to write clever software,
the gains from the latter are significant, as Larry's work pre- and
post-Perl has repeatedly demonstrated. When a language implementation
provides a feature like junctions that is arguably too clever by half to
start with, I'd rather there be a commensurate amount of cleverness in the
support of that feature.
Basically, I want the specified behavior to make sense as much as possible,
and for it to be easy to explain the places where it doesn't seem to make
sense. Even if it means we don't get that behavior in 6.0.0.
I'm thinking that the solution to this issue may be a little more
radical than to-date: don't permit junctions to be stored in $
variables! Instead, require junctions to use a twiggle, to alert the
reader that the surprises may be lurking.
my $x = 1|2; #error
my $|x = 1|2; # ok
Then you just need to invent some syntax to say that collapse is (or
perhaps isn't) desired:
if [[ $|x > 1 ]] { say "$|x collapsed" }
The most important thing that this does is that it leaves open the
option to allow "$" variables to hold junctions in some future version
of Perl, without that future version being constrained by legacy semantics.
