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
