Nathan Torkington wrote:
>
> David L. Nicol writes:
> > Any subroutine declaration, for instance
> >
> > sub Cmp:infix($$){
> > return uc($_[0]) cmp uc($_[1])
> > };
> >
> > implicitly sets up a "catch unknown-keyword:Cmp" routine; that is,
> > it installs the name of the function in a place the clarifier will know
> > to look for the definition.
> >
> > It doesn't convert it to opcodes, doesn't "parse" it yet, just stores
> > the token string.
> >
> > Later, while parsing some expression or other, Cmp is encountered.
> >
> > BAREWORD:Cmp is looked up in the whaddayaknow table, and there it is,
> > an infix subroutine taking two scalar arguments, so if that makes sense
> > with what is in front of and behind it, it gets evaluated as such.
>
> Ooookay. I think there's compile-time and run-time confusion here.
> Cmp will get *evaluated* at run-time. But the decision on what it is
> is made at compile-time.
>
> I'd just been picturing:
>
> sub Cmp :infix { ... }
>
> primes the parser to accept Cmp as an infix subroutine call.
> When the parser sees:
>
> SOMETHING Cmp SOMETHING
>
> it rewrite it as
>
> Cmp($foo, $bar)
>
> I don't see the need for exceptions to manage that.
>
> I also wonder how to specify the operator's precedence.
>
> Nat
"primes the parser" is what I am talking about. I see
exceptions as a very small, constant thing. I'm very far away from
"main stream" in this but I have what I think is a clear idea of
how it would all work together.
