Front page | perl.perl6.language |
Postings from April 2006
TSA wrote:
> I *still* don't understand the problem this long dot is trying
> to solve.
It's trying to solve the fundamental ambiguity of:
foo .bar
Which might be:
foo().bar
or might be:
foo(.bar)
The way we solved it is by saying that, anywhere a term is expected, a
sequence matching:
/\s+ \. [<ident>|<brackets>]/
is always a unary dot method call.
The reason we chose that is because we think that things like this:
method describe {
say .name;
say .rank;
say .serial_num;
}
and this:
given %data {
.<name> = join .<sep>, ucfirst .<first>, uc .<family>
}
will be common. And that it's much easier to understand such constructs if a
"gappy dot" *always* means unary dot, regardless of what preceded it.
That leaves a problem for people who want to line up method calls, or cascade
them over multiple lines. So we need a way to indicate that a "gap-dot"
doesn't mean unary method call. Which means we need a way to prevent perl6
from expecting a term, where a term is normally expected. Which we chose to do
by providing a postfix that indicates "more expression to come yet" or "don't
switch back to expecting a term here".
And the postfix Larry decided upon (rightly, I believe) was dot.
Damian
Thread Previous