David Wheeler [mailto:david@;wheeler.net] wrote:
> The problem with this is that you have explicitly introduced true and
> false into the language, and have therefore destroyed the utility of
> context:
>
> my boolean $bool = 0; # False.
> my $foo = ''; # False context.
> if ($foo eq $bool) {
> # Oops!
> }
If I am not mistaken, we already have explicitly introduced
true and false into the language:
my $bar = 0 but true;
my $bas = 0 but false;
A boolean type is therefore not quite as big a stretch as
you imply.
But we still have to deal with the expression issue:
if ($bar eq $bas) {} # true
if (?$bar eq ?$bas) {} # false
my $bool = true;
if ($bool eq $bar) {} # ???
Presumably, there exist rules for implicit casting when
comparing objects of different types. If we have a rule
that says that "if either operand is a boolean, then both
are compared as booleans", then things would work just
fine (except the the things I haven't considered ;-)).
The question of "what is C<true>" is really an implementation
issue. It could be a superposition of all true values; or it
could just be a predefined value, that has some special magic
associated with it. Perhaps its just a keyword, whose context
determines whether it is a value, or a property.
Dave.
