On Tue, 8 May 2012, jn...@jnthn.net via RT wrote:
On Mon May 07 16:21:12 2012, gfldex wrote:
package A { class Str {}; our sub foo() { return Str.new } }
This type cannot box a native string
Run it with -e and you see it's actually a compile-time error too:
===SORRY!===
This type cannot box a native string
Looking in to what happens, things go wrong like this.
* You change the meaning of Str
I do not agree here. S10 says: "Likewise every typename has an associated
package namespace, even if unused.", as I understand it I therefore do not
change the bahaviour of CORE::Str but add GLOBAL::A::Str . When I call
A::foo I expect to get a A::Str that does nothing and should not interfere
with CORE::Str . What is the point in having namespaces if the compiler
ignores it?
* The compiler now wants to create a string constant (as part of
installing &foo in the package, I think)
The question is what Str it should use.
* It looks up the Str type
* Your Str type doesn't actually work like a replacement for CORE::Str
should, so that fails
Im not sure if I actually wanted to overwrite CORE::Str, probably not.
(Warning, rethorical question incomming!) Where can I find a complete list
of built-ins so I can keep track of what names I should not use in my
user-defined namespace?
Quite frankly, that list is fairly long already and you can't really
expect new users (read: all those perl5 folk we want to convert) to keep
track of it.
So, this is working as designed. Generally, Perl 6 does not draw a
distinction between built-ins and user-space things; it goes against the
goal of language extensibility.
Fair enough, overwriting builtins may or may not be a good idea. However,
the error message does not indicate what the problem is. The first thing I
thought after reading it was: "What type and what native string? I never
did any native string!".
A warning that I define a type in my very own namespace, that is then
going to be used by the compiler instead of a built-in might help a lot.
Don't get me wrong. Extensebility is great to have. From the perspective
of a language implementator it makes perfectly sense. From a #perl6user
perspective it's quite confusing.
I can't really put my finger on the spot but there is something wrong
here. :-|
have a nice day
