RE: join() and split() to respect string overload operations

On Tue, 08 Jun 2010, Paul LeoNerd Evans wrote:
> On Mon, Jun 07, 2010 at 09:03:18AM -0700, Jan Dubois wrote:
> > I don't quite get how this would not work as long as you also have a
> > well-behaved overload for 'eq' and '""'.

[...]
 
> > Or would these identities also be
> > broken:
> >
> >    substr( $str . "x", 0, len $str ) eq "$str"
> >    substr( "x" . $str, 0, 1 ) eq "$str"
> >
> >    substr( $str, 0, 1 ) . substr( $str, 1 ) eq "$str"
> >
> > If these work, but yours don't, then I wouldn't consider the complete
> > set of overloads to be self-consistent.  If the these later identities
> > are broken as well, could you give an example of how to do it?
> 
> But, these identities -are- broken, because of the "squashing to plain
> string" that happens on the right-hand side.

Ok, in that case I don't consider your "eq" overload to be well-behaved:

Any implementation that doesn't return a true value for

    $str eq "$str"

is broken and a misuse of the overload mechanism IMO because it no
longer preserves string semantics and should be implemented as a plain
method instead.

You are of course free to abuse the mechanism any way you want, but you
cannot really claim that join/split/substr don't respect string overloading
if you aren't doing it yourself properly either.

Cheers,
-Jan